SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

FINAL STAFF REPORT

Rule 4694 (Wine Fermentation and Storage Tanks)

December 15, 2005

Prepared by: Daniel T. Barber, Ph.D., Air Quality Specialist

Reviewed by: George Heinen, Supervising Air Quality Engineer

Samir Sheikh, Permit Services Manager

Ted Strauss, Supervising Air Quality Inspector 

Maria Stobbe, Planning Manager

I. SUMMARY

A. Reasons for Rule Development and Implementation

The San Joaquin Valley Air Basin (SJVAB) is classified as an extreme ozone 

nonattainment area and a serious PM10 nonattainment area for the health-based 

air quality standards established by the federal Clean Air Act. The SJVAB is also 

classified as severe nonattainment for the California ozone standard and 

nonattainment for the California PM10 standard.

This rulemaking project is part of the District’s ozone and particulate matter 

attainment strategies. As such, this project is subject to the following state and 

federal requirements:

1 Ozone and PM10 attainment plans need to implement control measures 

as expeditiously as practicable, and provide for attainment. Clean Air Act 

(CAA) Section 172(c)(1)

2 Ozone attainment plans need to assure that reasonably available control 

technology (RACT) for volatile organic compounds (VOC) and NOx is in 

use at major sources and on source categories subject to control 

technology guidelines. CAA Sections 182(b)(2), 182(f)

3 PM10 attainment plans for serious PM10 nonattainment areas need to 

assure that the best available control measures (BACM) for the control of 

PM10 shall be implemented no later than 4 years after the date the area is 

classified (or reclassified) as a Serious Area. CAA Section 189(b)(1)(B)

4 BACM provisions in attainment plans should include the application of 

best available control technology (BACT) to existing major stationary 

sources. (Federal Register 8/18/94)The control requirements for major 

stationary sources of PM10 also apply to PM10 precursors (precursors for 

PM10 in the SJV are VOC, NOx, SOx). CAA Section 189(e) 
5 Ozone attainment plans should provide for best available retrofit control 

technology (BARCT) for existing permitted sources. California Health & 

Safety Code (H&SC) Section 40919(a)(3)

6 Ozone attainment plans should include “all feasible control measures.” 

H&SC Section 40914(a)(2) 

To satisfy the attainment goals of the ozone and PM plans, this rulemaking 

project will seek to obtain as much emission reduction from the source category 

as is expeditiously practicable, technologically feasible, and economically 

reasonable, as determined by the District’s Governing Board. The rulemaking 

project is also intended to satisfy the state and federal requirements identified 

above.

B. Description of the Project 

The District’s 2003 PM10 Plan and the 1-hour Ozone Plan identify the need for 

control measures to reduce VOC emissions from wineries. These plans identify 

wine fermentation and wine aging as two winery processes that produce 

significant VOC emissions. This project, Rule 4694 (Wine Fermentation and 

Storage Tanks), focuses on developing a control measure to reduce VOC 

emissions from tanks used in wine fermentation and wine storage. District staff 

will continue to investigate the feasibility of developing control measures to 

reduce VOC emissions associated with wine aging. In addition, District staff will 

begin investigating VOC emissions associated with the production, storage, and 

aging of other alcohol containing products, such as brandy and distilled spirits.

II. BACKGROUND

A. Current District Regulations

The District’s prohibitory rules do not currently regulate wine fermentation and 

wine aging. Rule 4623 (Storage of Organic Liquids) limits VOC emissions from 

the storage of organic liquids, however, Section 4.1.4, exempts tanks used in 

wine fermentation and for storage of resulting products, by-products, and spirits.

On March 15, 2002, Rule 4623 was submitted to the EPA along with other 

revisions to California’s State Implementation Plan for Achieving and Maintaining 

the National Ambient Air Quality Standards (SIP). On April 25, 2003, the EPA 

published in the Federal Register a proposed simultaneous limited approval and 

limited disapproval of Rule 4623, citing deficiencies in Rule 4623 that conflict with 

Section 110 of the Federal Clean Air Act (FCAA). Although not identified as a 

rule deficiency, EPA also expressed concern that Rule 4623 added an exemption 

for tanks used in wine fermentation and storage of resulting products, byproducts, and spirits. EPA considers VOC emissions from this source category 

to be significant and recommended further study and analysis.
III. DISCUSSION

A. General Process Description

Wine is an alcoholic beverage produced by fermentation of sugars in fruit juices, 

primarily grape juice. In general, wines are classified into two types according to 

alcohol content: table wines (7 to 14 percent alcohol, by volume) and dessert 

wines (17 to 22 percent alcohol, by volume). Dessert wines may achieve their 

higher alcohol content by the addition of distilled spirits (fortified wine) or by 

fermentation of higher sugar content juices. Table wines are further subdivided 

into still and sparkling categories, depending on the CO2 content retained in the 

bottled wine. Sparkling wines are often classified by the method used to achieve 

the CO2 content in the wine. Still table wines are further divided, based on color, 

into three groups: red, white, and rosé (or blush). In terms of overall production, 

still table wines represent the majority of table wines produced within the San 

Joaquin Valley. Consequently, the following discussion will focus on production 

of still table wines. 

Wine making involves three major steps: grapes are harvested, crushed, and 

then fermented. For this rule making processes, District staff is primarily 

interested in the wine fermentation step, which is typically a batch process. 

Other sources of fugitive emissions associated with wine production are bulk 

wine handling and bottling processes. Limited data are available to assist District 

staff in characterizing fugitive emissions from these activities. However, it 

appears that fugitive emissions from these sources warrant further consideration. 

For taxation purposes, the U.S. Department of the Treasury, Alcohol and 

Tobacco Tax Bureau (TTB) requires winery operators to file monthly reports 

detailing production, processing, and storage activities. According to the TTB, 

losses associated with wine handling and bottling routinely occur. Annual 

production losses vary, but in general, losses on the order of three (3) to five (5) 

percent could be within the norm. Applying a three (3) percent loss to the 

District’s 2002 wine production (337,968,011 gallons), equates to a loss of 

1,216,685 gallons of ethanol, which translates into potential annual emissions of 

about 4,500 tons of VOCs. The Wine Institute has commented that loses are 

between 0.5% and 3%. District staff has not found information that would assist 

in assessing how closely these potential losses reflect actual losses within the 

SJVAB. 
B. Source Description

The District’s 2003 PM10 Plan, and 1-hour Ozone Plan identify the need to 

address emissions of volatile organic compounds (VOC) from wine fermentation 

and wine aging processes occurring in the SJVAB. The 2003 PM10 Plan 

estimates that ethanol emissions from wine fermentation, bulk-wine storage, and 

barrel aging of wine and brandy averaged 7.0 tons per day (TPD) in 1999. The 

1-hour Ozone Plan estimates baseline ethanol emissions from wine fermentation 

and bulk-wine storage will be 2.1 tons per day in 2010, and projects emission 

reductions of 0.7 tons per day for a wine fermentation and storage control 

measure.

Seventy percent of the State of California’s wine production occurs within the 

SJVAB. The majority of wine production in the SJVAB occurs at large wineries, 

with annual wine production capacities of tens of millions of gallons. In 2002, 18 

wineries in the District had annual permitted production volumes ranging from 5 

million to greater than 50 million gallons. These 18 wineries accounted for 95% 

of the District’s emissions from wine fermentation. Of the 109 wineries operating 

in the SJVAB in 2002, 70% of the wineries had annual production volumes of 

less than 200,000 gallons, and 58% of the wineries had annual production 

volumes of less than 2,000 gallons.

C. Emissions Inventory

An emissions inventory has two components, the amount of emissions per unit of 

activity and the total amount of activity. In the case of wine fermentation, the unit 

of activity is gallons of must fermented into wine. Because of processing 

differences, red wine fermentation produces about 2.5 times more VOC 

emissions than white wine fermentation. Red wine has an emissions factor of 

6.2-lb VOC/1,000 gallons, and white wine has an emissions factor of 2.5-lb/1000 

gallons of fermented must.

Statistics characterizing the total amount of wine fermentation occurring in the 

SJVAB were obtained from The U.S. Department of the Treasury, Alcohol and 

Tobacco Tax Bureau (TTB). In 2002, 337,968,011 gallons of wine were 

fermented in the SJVAB. TTB statistics are for total wine fermentation and do 

not report volumes of red wine and white wine produced. To estimate the 

volumes of red wine and white wine produced in the District during 2002, the TTB 

statistics were apportioned into volumes of red and white wine produced, using 

ARB methodology. ARB methodology uses the percentages of grapes crushed 

for red wine and white wine, as reported in the California Grape Crush Report. In 

2002, 60% of the grapes were crushed for red wine and 40% of the grapes were 

crushed for white wine production. Using these percentages, total gallons of 

wine fermented in the District would be apportioned into approximately 198 

million gallons of red wine and 140 million gallons of white wine.

The emissions inventory can be estimated by applying the respective emission 
factors to gallons of red wine and white wine fermented in the District. Based on 

2002 fermentation data, the emissions inventory for wine fermentation is 

estimated to contain 613 tons VOC emissions from red wine fermentation and 

175 tons VOC emissions from white wine fermentation. Total annual VOC 

emissions from wine fermentation in the SJVAB are an estimated 788 tons per 

year.

The Wine Institute has stated that use of the Crush Report statistics overstates 

the emissions inventory. The Wine Institute has opined that the Crush Report 

does not account for red grape varieties that are fermented into blush wines, 

whose emissions are similar to white wines. A Wine Institute survey of 7 large 

wineries in the SJVAB shows that about 40% of their production was red wine 

and about 60% was white wine. Using the Wine Institute’s percentages, the 

emissions inventory for wine fermentation would be estimated to contain 398 

tons VOC emissions from red wine fermentation and 262 tons from white wine 

fermentation, annually. Total annual VOC emissions from wine fermentation 

would be 660 tons per year, based on Wine Institute survey data. 

In the absence of definitive data on the amount of red wine and white wine 

produced in the District, the annual VOC emissions from wine fermentation are 

presented in this report as a range from 660 to 788 tons. Averaged over 365 

days, daily emissions range from 1.8 to 2.2 tons per day. Wine fermentation is 

seasonal, corresponding to the grape harvest. In the SJVAB, fermentation 

typically occurs over a 90 to 120 period, resulting in seasonal daily averages of 

7.3 to 8.8 tons per day, or 5.5 to 6.6 tons per day for the respective fermentation 

period.

In 2002, 75% of annual fermentation emissions occurred during September and 

October. This period coincides with when the SJVAB experiences the greatest 

exceedance of the NAAQS for one-hour ozone, in both frequency and 

magnitude. Additional information on emissions can be found in Appendix B, 

Emissions Reduction Analysis.

IV. EMISSIONS CONTROL

The US EPA’s RACT/BACT/LAER Clearinghouse (RBLC) database contains 

case-specific information on the "Best Available" air pollution technologies that 

have been required to reduce the emission of air pollutants from stationary 

sources (e.g., power plants, steel mills, chemical plants, etc.). This information 

has been provided by State and local permitting agencies. The RBLC contains 

no examples of controlling wine fermentation emissions. Additional literature 

searches produced no examples of fermentation emission control being 

implemented worldwide.

The District has prepared a BACT guideline for Ethanol Fermentation Process 
Tanks (Guideline 4.12.4) for ethanol production from corn fermentation. 

Guideline 4.12.4 establishes a 99.5% VOC emissions control efficiency using a 

fermentation-wet scrubber vented to a CO2 recovery plant with a condenser and 

high-pressure scrubber; or equivalent.

Differences between wine fermentation and ethanol for fuel production 

necessitates consideration of alternative control technologies. Of specific 

concern is treatment of the wastewater from the wet scrubber. During corn 

fermentation, wastewater from the wet scrubber is conveyed back to a slurry tank 

and reused in the manufacturing process. Wine is a food product and lacks a 

similar production process. As a control technology for wine fermentation, wet 

scrubbers would require alternative wastewater treatment or disposal methods. 

Guideline 4.12.4 identifies thermal oxidation with 98% VOC control as an 

alternative technology. Thermal oxidizers have been successfully used in 

different industrial settings operating in the District and are readily available. 

District staff considers regenerative thermal oxidizers to be an acceptable control 

technology for use in controlling VOC emissions from wine fermenters.

In 1990, a demonstration program evaluating control of ethanol emissions from 

wine fermenters was conducted at the E. & J. Gallo Winery in Fresno, California . 

The study used a prototype emissions capture system. The design of the VOC 

capture system allowed fermentation emissions to vent naturally through a 

manway located at the top of the tank. The VOC capture system consisted of an 

emissions collection hood, located above the manway, connected by ductwork to 

a VOC control device. The collection hood was larger than the manway and was 

suspended above the opening, creating an air gap between the tank and the 

hood. The design included a fan with a flow-rate sufficient to pull emissions into 

the collection hood and force the emissions through the ductwork to the 

emissions control device. Based on results reported in the Gallo study, District 

staff considers it reasonable to expect similar emissions collection systems to 

have a capture efficiency of at least 90%.

Achieving an emissions capture efficiency of 90% and an emissions destruction

efficiency of 95% would result in an overall emissions reduction efficiency of 

86%. A report submitted to the District by the Wine Institute includes a 

conceptual design for collection system that eliminates the air gap, achieving a 

closed capture system. A closed capture system is expected to have a capture 

efficiency of 100%.
A. Fermentation Emissions Control Technology

Ethanol is the primary VOC produced during wine fermentation. Many different 

types of established technologies can be used to control ethanol emissions. Five 

types of VOC controls are:

1. Oxidation (conversion of the VOC to CO2);

2. Absorption (“scrubbers”, which transfer the VOC in air emissions to a 

liquid waste stream);

3. Adsorption (often using activated carbon, which transfers the VOC in the 

air onto a solid substrate);

4. Condensation (conversion of the VOC gases into liquids); and 

5. Biological control systems (e.g., bio-filters or bio-scrubbers)

Another option for controlling ethanol emissions from fermentation is reduction in 

fermentation temperatures. Temperature control as a method of reducing 

fermentation emissions is based on the relationship between fermentation 

temperature and evaporative ethanol loss.

General information on available control technologies follows.

Adsorption Vapor Recovery

Adsorption vapor recovery is accomplished by passing the VOC-laden gas 

through beds containing adsorbents that have a high surface area to weight ratio. 

Typical adsorbents are activated carbon, zeolite, or organic polymers. As the 

gas stream passes through the bed, organic compounds adsorb weakly onto the 

adsorbent’s surface. Adsorption of the hydrocarbon molecules proceeds until the 

available surface area is filled or saturated with VOC molecules. The VOC 

molecules are retained until the regeneration step, or disposal of the spent 

adsorbent.

Desorbing or removing captured VOCs regenerates the adsorbent. Decreasing 

the pressure, reducing the hydrocarbon concentration around the adsorbent or 

increasing the temperature of the bed can perform regeneration. A combination 

of these steps can also be used for regeneration. There are three basic types of 

adsorption systems available to recover or remove hydrocarbon vapors from an 

air stream. Two of these systems regenerate the adsorbent in-situ for reuse. The 

third system requires removal of the adsorbent to another site for regeneration.

The two systems that provide in-situ regeneration are: Pressure Swing 

Regenerated Systems and Thermally Regenerated Systems. The third type of 

system, which requires removal of the absorbent to another site for regeneration 

or disposal, is a once through single use or canister system. Canister systems 

can usually be purchased directly from the manufacturer.

Thermal Oxidation (Incineration)
A thermal oxidizer (TO) destroys VOCs by the process of combustion. A basic 

TO system consists of a combustion chamber, burner, stack, and combustion 

controls. All hydrocarbons are oxidized to carbon dioxide and water vapor by the 

proper mix of temperature, residence time and turbulence within the reactor 

chamber. Combustion of the contaminated gas stream occurs at high 

temperatures, normally 650oC to 870oC (1,200oF to 1,600oF) when treating low 

concentration streams. 

TO systems can be divided into recuperative or regenerative systems; based on 

methods used to increase operating efficiencies by capturing heat from the 

combustion process. Recuperative TO systems increase fuel efficiency by use of 

a gas pre-heating section and a heat recovery section. Heat recovery can be as 

high as 70%. A regenerative system provides extremely high thermal-energy 

recovery; up to 95% of heat energy can be recovered. Regenerative TO systems 

use a ceramic heat-exchange bed to preheat process air to within 5% of the 

oxidation temperature. PM10 and VOC conversion efficiencies range from 97% 

to 99.9% for recuperative and 95% to 99% for regenerative TO systems.

Catalytic Thermal Oxidation

A catalytic thermal oxidizer (CTO) is essentially a thermal oxidation unit with a 

catalyst module. These units are similar in design to recuperative units, except 

that VOCs are oxidized using precious metal or metal-oxide-based catalysts 

instead of open flames. Operating at about half the temperature of thermal 

oxidizers, catalytic units have smaller footprints and relatively low operating 

costs. Other industries have demonstrated typical VOC removal efficiencies of 

up to 98%.

Wet Scrubbing

The basic process involved in wet scrubbing is contacting a polluted gas stream 

with a liquid solution. During operation, gas flows upward through a packed 

column while scrubbing liquid flows down (by gravity) over the packing material. 

The counter-flow design principle offers optimal mass transfer. Gaseous 

contaminants are entrained in the liquid and the decontaminated gas stream 

flows out of the scrubber. Many scrubbing applications achieve emission 

reduction efficiencies of 99.9%. In a pilot study conducted by ARB in 1987, wet 

scrubbing demonstrated greater than 90% reduction in ethanol emissions.

Condensation, Refrigeration, and Cryogenic Systems

Condensation, refrigeration, and cryogenic systems remove organic vapor by 

condensing the target gases on cold surfaces. These cold conditions can be 

created by passing cold water through an indirect heat exchanger, by spraying 

cold liquid into an open chamber with the gas stream, by using a refrigerant to 

create very cold coils, or by injecting cryogenic gases such as liquid nitrogen into 

the gas stream. The concentration of VOCs is reduced to the level equivalent to 
the vapor pressures of the compounds at the operating temperature.

Removal efficiencies attainable with this approach depend strongly on the outlet 

gas temperature. For cold-water-based condensation systems, the outlet gas 

temperature is usually in the 40 to 50°F range, and the VOC removal efficiencies 

are in the 90% to 99% range depending on the vapor pressures of the specific 

compounds. For refrigerant and cryogenic systems, the removal efficiencies can 

be considerably above 99% due to the extremely low vapor pressures of 

essentially all VOC compounds at the very low operating temperatures of -70°F 

to less than -200°F. 

Biological Oxidation

Biological oxidation systems are a relatively new means of air pollution control. 

VOCs can be removed by forcing them to absorb into an aqueous liquid or moist 

media inoculated with microorganisms that consume the dissolved and/or 

adsorbed organic compounds. The control systems usually consist of an 

irrigated packed bed that hosts the microorganisms (biofilters). A presaturator is 

often placed ahead of the biological system to increase the gas stream relative 

humidity to more than 95%. The gas stream temperatures are maintained at less 

than approximately 105°F to avoid harming the organisms and to prevent 

excessive moisture loss from the media.

Biological oxidation systems are used primarily for very low concentration VOCladen gas streams. The VOC inlet concentrations are often less than 500 ppm 

and sometimes less than 100 ppm. The overall VOC destruction efficiencies are 

often above 95%.

Temperature Control

As demonstrated by the stoichiometric model developed by professors Williams 

and Boulton, UC Davis, ethanol loss during fermentation is driven by total sugar 

conversion and fermentation temperature. Lowering fermentation temperatures 

could result in lower ethanol emissions. However, there is a lack of empirical 

data supporting accurate characterization of the resulting emission reduction or 

establishment of the appropriate fermentation temperature limits. Actual 

emission reductions would be determined by complex interactions including 

factors such as non-isothermal fermentation, presence of the pomace cap in red 

wine fermentation, and starting and ending Brix levels. A draft technical 

assessment document prepared by ARB presents a hypothetical 15 percent and 

30 percent reduction in ethanol emissions from red wine and white wine 

fermentations respectively. The authors note, however, that emission reductions 

of that magnitude would probably be achieved in only a few isolated cases. 

Because of the lack of empirical data and the uncertainty of achievable 

emissions reductions, temperature control is not considered a viable VOC control 

option at this time.
B. RACT/BARCT for Fermentation Emissions Control

The San Joaquin Valley Unified Air Pollution Control District is the first district in 

the nation to propose controlling VOC emissions from wine fermentation tanks. 

Thus, there is no existing rule or regulation establishing RACT, BARCT, or BACT 

for the source category. For the past two-years District staff has worked to 

characterize fermentation tank emissions and their control. A detailed discussion 

of fermentation emissions and potential emission reductions are presented in 

Appendix B. In establishing potential VOC control requirements, District staff 

considered both technical feasibility and cost effectiveness. A detailed 

discussion of cost effectiveness is presented in Appendix C. 

Staff has concluded that while there is a definite link between tank volume and 

fermentation emissions, process throughput and type of wine being produced are 

the major determining factors. Thus, cost effectiveness varies widely with tank 

size and throughput. District staff considered basing VOC control requirements 

on a combination of wine type and throughput. The District’s Permits database 

indicates that the 13 largest wineries have a combined fermentation volume of 

484,270,568 gallons. Dividing this figure by the industry’s total wine production 

for 2002 (337,968,011 gallons), shows that the wine industry could have about 

40% excess fermentation tank capacity. With this level of excess capacity, VOC 

control requirements based on throughput limits would not likely result in real 

emission reductions.

District staff concluded that to achieve real reductions it would be best to 

structure VOC control requirements based on tank size, and provide exemptions 

for wine type, and fermenters that are unlikely to achieve a throughput that would 

be considered economical to control. As indicated in Appendix C, Table-1 and 

Table-2, it is possible to demonstrate a theoretical combination of tank size, wine 

type, and throughput that results in a cost effective controls. For fermenters 

processing red wine cost effective control could begin at 50,000 gallons. For 

fermenters processing white wine cost effective control could begin at 300,000 

gallons. The critical factor for those determinations is the assumed number of 

batches being processed. Both estimates assume each tank processes the 

maximum theoretical number of batches. For red wines, the theoretical 

maximum was an assumed 12 to 18 batches per year. For white wines, the 

theoretical maximum was an assumed 6 to 9 batches per year. Theoretical 

maximums are seldom realized. Average batches processed per tank range 

from 5 to 6 batches for red wine and 2 to 3 batches for white wine. Cost 

effectiveness is very sensitive to process rate, so actual cost effectiveness would 

be higher than indicated in cost effectiveness analysis presented in Appendix C 

for Scenario-1.

The analysis in Scenario-3 uses an average of 5 to 6 batches per year for red 

wine and is considered to be reflective of actual process parameters. It had been 
previously concluded that control of white wine fermenters processing 6 to 9 

batches of wine per year was marginally cost effective for tanks 300,000 gallons 

or larger. Thus, white wine fermenters processing only 2 to 3 batches per year 

were not evaluated in Scenario-3. The VOC control requirements presented in 

the previous draft rule were developed in consideration of Scenario-3. 

Staff structured VOC control requirements in the previous draft rule taking in 

consideration wine type, tank size and cost of controls. Exemptions for wine type 

and fermenter size were provided. The draft would require operators to install 

and operate VOC controls on red wine fermenters that have an internal volume 

of at least 50,000 gallons. The VOC control system would achieve a combined 

capture and control efficiency of 86%. District staff considers these requirements 

to constitute BACT/BARCT for wine fermentation tanks. Achievable emission 

reductions from the proposed control requirements range from 474 to 308 tons 

VOC per year, and are summarized in Table-1.

Table-1: Previous Draft Rule 4694 Emission Reductions

Baseline for a Ratio of 

60% Red Wine and 

40% White Wine 

(788 tons/year)

Baseline for a Ratio of 

40% Red Wine and 

60% White Wine.

(660 tons/year)

Exemption/Activity Annual Tons Annual Tons

Small Winery - Red Wine 

Fermentation 21.5 13.9

Small Winery – White Wine 

Fermentation 9.6 14.4

Wine Fermenters 

Exclusively Fermenting 

White Wine

166 248

Red Wine Fermenters < 

50,000 gallons 12.3 8.0

Wood or Concrete 

Fermenters 18.4 11.9

Transfer of Wine at 40 Brix 9.9 6.4

Total Exemptions 237.3 302.2

Adjusted Baseline 550.9 357.9

Achievable Reductions at 

86% Capture & Control 474 308

As discussed in Section VI of this report, there is considerable uncertainty 

associated with technical feasibility and cost effectiveness of controlling wine 

fermenters. To provide time for industry and the District to better understand 

those issues, staff is proposing a market-based approach for Rule 4694. 

Operators would be required to achieve a 35% reduction in their total 
fermentation emissions. Only small wineries would be exempt from fermentation 

VOC control requirements. As presented in Table-2, exempting small wineries 

would result in uncontrolled emissions of 43 to 36 tons per year. These 

emissions were subtracted from the baseline emissions, resulting in an adjusted 

baseline of 745 to 624 tons per year. A 35% reduction of the baseline emissions 

would result in achievable emission reductions of 261 to 218 tons per year, and 

average daily emissions of 0.72 to 0.6 tons per day. This level of emissions 

reduction is consistent with the District’s attainment plans for the source category 

and is reasonable given the cost of control estimates and degree of uncertainty 

about potential impact on product quality.

Technical uncertainties and cost effectiveness are expected to be resolved as 

winery operators install fermentation emission controls. Until there are better 

data on technical feasibility and cost of control, District staff considers the 35% 

reduction in total fermentation emissions to constitute RACT for wine 

fermentation tanks.

Table-2: Current Draft Rule 4694 Emission Reductions

Baseline for a Ratio of 

60% Red Wine and

40% White Wine

(788 tons/year)

Baseline for a Ratio of 

40% Red Wine and

60% White Wine

(660 tons/year)

Exemption/Activity Annual Tons Annual Tons

Small Winery Exemption 43 36

Adjusted Baseline 745 624

Achievable Reductions at 

35% Control 260.8 218.4

C. Storage Tank Emissions Control Technology

VOC’s are emitted from wine handling and storage operations as volatilized 

ethanol. Wine is produced in the San Joaquin Valley by fermentation during the 

“crush” season, an approximate 12-week period coinciding with the grape 

harvest (late August to mid-November). Subsequently, the wine is transferred a 

number of times between storage tanks to perform various polishing operations 

such as “racking” (decantation for separation of sediment), filtration, malolactic 

fermentation (breakdown of malic acid to lactic acid and carbon dioxide), and 

bottling operations. Since the bottling process is a year-round operation, each 

batch of wine will have a definite residence time in storage, prior to bottling, 

which includes the time spent in performing the various post-fermentation 

polishing processes. The post-fermentation polishing operations result in 

“working losses” from the storage tanks since they require draining and filling the 

tanks several times. Storage prior to bottling generates “breathing losses” from 
the tanks. 

Since ethanol in water constitutes an organic liquid, the US EPA TANKS program 

can be utilized to determine the estimated VOC (ethanol) emissions. However, 

obtaining accurate results from the TANKS program requires that the organic 

liquid be accurately characterized in terms of vapor pressure of the liquid and the 

composition of the equilibrium vapor phase. Since ethanol and water are highly 

polar compounds, they form a non-ideal mixture, i.e., the mixture does not follow 

Raoult’s law, and, as a result, direct estimation of vapor pressure and equilibrium 

vapor phase concentration, based on pure component properties, is not practical 

and experimental data are required.

To effectively utilize TANKS to estimate VOC emissions from wine storage, 

experimental data supplied by the Wine Institute for the vapor pressure of 

ethanol over wine can be utilized, along with the assumption that water will 

behave ideally (a good assumption since the liquid phase is over 95% water on a 

molar basis). Use of the above data to calculate storage tank emissions is 

demonstrated by calculating a specific emission factor for VOC emissions from 

wine storage based on a “typical” San Joaquin Valley wine storage scenario:

Calculation Procedure:

1 Characterize wine in terms of molecular weight of liquid and vapor phase and 

the total vapor pressure over wine.

2 Input data, along with tank parameters into Tanks 4.0. Output from Tanks 4.0 

is total vapor phase emissions (including water) in lb/year.

3 Back calculate ethanol emissions from vapor phase ethanol concentration.

Assumptions:

1 The average ethanol (EtOH) concentration of stored wine is 12 vol% (most 

wine is 10-12 %, use upper end of range to account for fortified wines which 

can be as high as 20%).

2 Average wine storage temperature is 50oF since wine storage is typically 

refrigerated.

3 Post fermentation, average wine handling for storage and post fermentation 

treatment is equivalent to 6 turns of the average storage1.

4 Specific gravity of ethanol is 0.79784 @ 50oF or 6.65 lb/gal (Perry’s Chemical 

Engineer’s Handbook, 5th Edition, Table 3-112).

5 Specific gravity of 12 vol % ethanol in water is 0.98145 @ 50oF or 8.18 lb/gal 

(Perry’s Chemical Engineer’s Handbook, 5th Edition, Table 3-112).
6 Density of water is 8.34 lb/gal.

7 Partial pressure of ethanol over wine with 12% ethanol.

8 Water behaves ideally according to Raoult’s Law, i.e., partial pressure of 

water in the vapor phase is the product of the liquid phase water mole fraction 

and the vapor pressure of pure water at the system temperature.

9 Average post fermentation storage is 6 months, October through March.

10 Average storage tank is a nominal 300,000 gallons (based on an industrytypical range of 100,000 to 600,000 gallon capacity for storage tanks).

11 The storage tank is equipped with a pressure-vacuum valve.

Calculations:

1. Calculate molar fractions and average molecular weights for liquid and 

vapor phases:

Liquid Phase Molecular Weight (calculation basis 1000 gallons of 12 vol% 

wine)

Lb-mols EtOH = 1000 gal wine x .12 gal EtOH/gal wine x 6.65 lb EtOH/gal 

EtOH x 1mol EtOH/46.02 lb EtOH

Lb-mols EtOH = 17.3 lb-mols EtOH

Lb-mols H2O = 1000 gal wine x .88 gal H2O/gal wine x 8.34 lb H2O/gal 

H2O 

x 1mol H2O/18.02 lb H2O

Lb-mols H2O = 407.3 lb-mols H2O

Total Mols in 1000 gal wine = 17.3 + 407.3 = 424.6 mols

Xa = liquid mol fraction EtOH = 17.3/424.6 = 0.041

Xw = liquid mol fraction H2O = 407.3/424.6 = 0.959

Average Molecular weight of liquid = (0.041 x 46.02) + (0.959 x 18.02)

= 19.17

Vapor Phase Molecular Weight and Total Vapor Pressure Over Wine 
Total vapor pressure over wine is the sum of the partial pressure of EtOH 

plus the partial pressure of water:

Total Pressure (Pt) = Partial Pressure EtOH (Pa) + Partial Pressure Water 

(Pw) 

Pa is taken from Attachment I for 12 vol% wine.

Pw = Liquid Mol Fraction Water x Vapor Pressure Pure Water at System 

Temperature (VPw)

or,

Pw = 0.959 x VPw , where VPw is taken from The Steam Tables, J. 

Keenan et al.

The mol fraction EtOH in the vapor phase is then calculated as:

Ya = Pa / Pt ,and the average molecular weight (AMW) of the vapor phase 

is then calculated as:

AMW = (Ya x Molecular Weight EtOH) + ((1- Ya) x Molecular Weight Water)

= (Ya x 46.02) + ((1- Ya) x 18.02)

Performing the above calculations for temperatures ranging from 40oF to 100oF 

yields the following Table-3:

Table-3: Characterization of Vapor Phase Over 12 vol% Wine

oF

Pa(in wine) 

Psia

Pw

psia

Pt(wine)

psia Ya AMW

40 0.0463 0.1217 0.1630 0.2840 25.97

50 0.0669 0.1780 0.2376 0.2816 25.90

60 0.0953 0.2563 0.3411 0.2794 25.84

70 0.1340 0.3632 0.4823 0.2778 25.80

80 0.1860 0.5073 0.6725 0.2766 25.76

90 0.2552 0.6988 0.9253 0.2758 25.74

100 0.3461 0.9503 1.2574 0.2752 25.73

Since the average storage temperature has been determined to be 50oF, the 

vapor phase is characterized by an EtOH mol fraction of 0.2816 and an average 

molecular weight of 25.90 per the calculations above.

2. Calculate Expected Vapor Emissions Via Tanks 4.0 based on the above 

characterization:
Input total vapor pressure for 12 vol% wine (from table above), and the average 

molecular weights for vapor and liquid determined above, into TANKS. In order to 

simulate an average temperature of 50oF, the calculation was performed using 

meteorological data for Fort Wayne, Indiana, which has an average annual 

temperature near 50oF.

Output from the above indicates annual vapor emissions of 221.3 lb/year.

3. Back-calculate the EtOH emissions:

EtOH emissions = (221.3 lb-vapor/year) x (1 mol vapor/25.90 lb) x (0.2816 mol

EtOH/Mol Vapor) x (46.02 lb EtOH/mol EtOH) 

EtOH emissions = 111.7 lb for six month storage of 300,000 gal of wine at 12 vol 

% ethanol

Emission Factor = 111.7/300 = 0.372 lb EtOH/1000 gal wine stored.

In 2002, 337,968,011 gallons of wine was fermented in the District. Storing all of 

the 2002 wine fermentation in the District until bottled, would result in annual 

storage emissions of 63 tons of VOC, as illustrated as follows:

2000 lb

1 ton

1000 gal stored

0.372 lb EtOH

Year

337,968,011gal EtOH EtOH Emiss ions = x x

Not all wine fermented in the District is bottled in the District, thus actual storage 

emissions are likely lower than estimated. According to District Permit To 

Operate application data, there are over 4,000 tanks potentially used for storing 

bulk wine in the District.

D. Effect of Pressure-Vacuum Relief Valve on Wine Storage Tank 

Emissions

To assess the affect of pressure-vacuum relief valves and ambient temperature 

swings on wine storage tank emissions, two runs with Tanks 4.0 were performed. 

Both analyses are based on a 100,000-gallon storage tank installed in Fort 

Myers, FL, which has an ambient temperature of near 75oF. This should provide 

a conservatively high estimate of tank breathing losses, since it is assumed there 

is no temperature control on the tank, and the tank is subject to the full daily 

swing in ambient temperature. The tank is assumed filled to two feet below the 

roof seam.

One analysis is based on the tank having a pressure-vacuum relief valve with the 

default settings. A breathing loss of 65.19 lb/year (water and ethanol) was 

calculated per Tank 4.0. A second analysis was performed using the same 

assumptions, except the pressure-vacuum relief valve was deleted. This 
analysis resulted in a breathing loss of 68.29 lb/year (water and ethanol). 

Comparison of the results indicates use of a pressure vacuum relief valve 

reduced emissions by 3.1 lb/year. Ethanol emissions of 1.6 lb for annual storage 

of 100,000 gallons of wine were calculated per the following:

mol EtOH

46.02lb EtOH

mol vapor

0.2816 mol EtOH

25.90 lb

1mol vapor

year

3.1lb vapor EtOH emissions = x x x

The resulting emissions factor is 1.6 lb EtOH/100,000 gallon capacity storage 

tank per year.

According to the District’s permit database, the thirteen largest wineries in the 

District have 4085 storage tanks, with an average storage capacity of 145,000 

gallons. Emission reductions of 3.3 tons per year resulting from use of pressurevacuum relief valves were calculated according to the following:

2,000lb

1 ton EtOH emissions = 1.6lb EtOH/100,000 gallon tank/year x 4,085 tanks x

E. RACT for Wine Storage Tank Emissions Control 

Two operational practices currently in place on bulk wine storage tanks in use at 

large wineries in the District are use of pressure-vacuum relief valves and 

temperature control. District staff considers use of pressure-relief valves, and 

temperature control to constitute RACT for bulk wine storage tanks.

V. WINE INDUSTRY CONCERNS

Throughout the rule development process, the Wine Institute has opposed 

provisions that would require operators to control VOC emissions from wine 

fermentation tanks. The Wine Institute challenges the technical feasibility and 

cost effectiveness of controlling VOC emissions from wine fermentation. The 

Wine Institute has requested that development of Rule 4694 be postponed until 

the technical issues are more fully understood. The Wine Institute cites the 

following as technical and operational risks associated with implementing VOC 

capture and control systems on wine fermentation tanks:

1 There is an increased risk of contaminating individual fermentation batches 

and cross-contamination between fermenters because of the common 

ducting installed between fermenters to collect VOC emissions.

2 The ductwork results in an increased risk of microbial contamination.

3 The control system may alter the fundamental characteristics of the wine, 

resulting in product devaluation.

District staff believes that it is technically feasible to reduce emissions from wine 
fermentation, without affecting product quality. VOC emission collection 

systems and VOC destruction devices are well known technologies in use in 

other industries that use fermentation processes, e.g. pharmaceuticals. District 

staff has found no evidence demonstrating that controlling fermentation 

emissions would have any affect on product quality.

The Wine Institute also recommended that rule development be abandoned on 

the basis that cost of controlling wine fermentation emissions is too expensive. 

An engineering study prepared for the Wine Institute estimates a cost of 

$30,962,000 for a proposed installation of VOC controls at the Gallo-Livingston 

winery. That report estimates cost effectiveness at $120,479/ton VOC controlled 

at that location. 

District staff has reviewed the Wine Institute report and believes that the report 

significantly over estimates the cost of control. In brief, the District’s analysis 

concludes:

1 The estimate includes significant costs that are specific to the GalloLivingston facility or to Gallo facilities in particular. (Estimated Impact 

$6,729,000)

2 The design is based on a worst–case approach for all potential operating 

scenarios. No design optimization or simplification has been carried out, nor 

have operations improvements been considered. (Estimated Impact 

$7,263,000)

3 Capacities of the estimated capture and control systems are unnecessarily 

large. The District estimates that the size of the control systems could be 

reduced by at least 37%. (Estimated impact $1,851,000)

4 Estimated operating costs have not taken full advantage of the efficiencies of 

the proposed equipment and over estimates operational labor requirements. 

(Estimated impact $293,400/year) 

Based on an adjusted estimate, the capacity of the 60 tanks included in this 

estimate, and the industry’s reported 4 to 5 turns per tank per season, the District 

estimates cost effectiveness ranging from $42,000/ton-VOC to $53,000/ton-VOC 

for a non-site specific installation of this size. Details of District staff’s cost of 

control analysis are presented in Appendix C, Cost Effectiveness Analysis.

VI. MARKET-BASED APPROACH 

District staff believes that it is technically feasible to reduce emissions from wine 

fermentation without affecting product quality. VOC emission collection systems 

and VOC destruction devices are well known technologies in use in other 

industries that use fermentation processes and that must meet stringent federal 

safety standards, e.g. pharmaceuticals. However, there is limited data specific to 

controlling VOC emissions from wine fermentation. As presented in Appendix C, 
Cost Effectiveness Analysis, of this draft staff report, three cost effectiveness 

scenarios were considered. These estimates show costs of controlling VOC 

emissions from red wine fermentation ranging and average of $27,000/ton-VOC 

reduced to $120,479/ton-VOC reduced. Cost effectiveness of controlling white 

wine fermentation emissions were higher, because of the lower emissions 

associated with white wine fermentation. These three scenarios present a wide 

range in the cost effectiveness of controlling VOC emissions from wine 

fermentation. Actual average cost of control is expected to be somewhere in 

between.

The lack of experience in controlling emissions from wine fermentation and cost 

effectiveness are intrinsically linked. Control system designs are not optimal, 

translating into higher costs of control. Likewise, it is understandable that the 

wine industry’s lack of experience in controlling emissions from wine fermentation 

translates into concerns about product quality. Other industries have learned 

how to cost effectively control their air emissions without affecting product quality. 

It is reasonable to expect that the wine industry will do likewise. To achieve 

attainment of state and federal ambient air quality standards by 2010, the District 

cannot delay mitigating emissions from wine fermentation.

The District has restructured Rule 4694 to incorporate a market-based approach 

that achieves emission reductions consistent with the plan, expedites obtaining 

emission reductions from wine fermentation, and provides the wine industry time 

to develop expertise in controlling fermentation emissions without devaluating 

product quality. The restructured rule would require operators of wineries 

emitting at least 10 tons VOC emissions annually from wine fermentation to 

reduce or mitigate 35% of their total wine fermentation emissions. The 10-ton 

emissions threshold captures wineries responsible for about 95% of the 

fermentation emissions in the District. Thus, the exemption results in an adjusted 

annual emissions baseline of 624 to 745 tons of VOC emissions from wine 

fermentation.

Requiring operators to achieve a 35% reduction in fermentation emissions, or 

equivalent reductions through mitigation measures would result in annual VOC 

emission reductions of 218 to 261 tons. When these reductions are averaged 

over 365 days per year, daily average emission reductions equal 0.6 to 0.72 tons 

per day. This level of reduction would achieve the emission reduction 

commitments contained in the District’s air quality attainment plans.

Operators could achieve the 35% reduction in facility-wide fermentation 

emissions by any combination of the following means:

1 Installing and operating VOC control systems on fermenters;

2 Obtaining surplus emission reductions from other emission sources; and

3 Paying into an Air Quality Impact Mitigation fund that would be administered 

by the District to obtain surplus emission reductions from other sources within 

the District.
A. Emission Reductions Versus a Command & Control Approach

The previous draft of Rule 4694 was structured as a command and control rule. 

Operators would be required to equip red wine fermenters subject to the rule with 

a VOC control system having a combined capture and control efficiency of 86%. 

Provisions within the rule would exempt small wineries, all white wine 

fermentation tanks, and fermentation tanks constructed primarily of wood or 

concrete from VOC control requirements. Also, the rule would allow fermenting 

must to be transferred to an uncontrolled tank, after reaching 4o Brix, or less. As 

presented in Table-1, on page 11 of this staff report, these exemptions and 

allowed activities would result in uncontrolled emissions ranging from 237 to 302 

tons per year. These emissions were subtracted from the fermentation 

emissions baseline, resulting in adjusted baseline of 551 to 358 tons per year. 

Applying an 86% capture and control efficiency to the adjusted baseline would 

result in achievable emission reductions of 474 to 308 tons per year, and 

average daily emission reductions of 1.3 to .84 tons per day.

The current draft of Rule 4694 is structured as a market-based rule. Operators 

would be required to achieve a 35% reduction in their fermentation emissions. 

Only small wineries would be exempt from fermentation VOC control 

requirements. As presented in Table-2, on page 12 of this staff report, 

exempting small wineries would result in uncontrolled emissions of 43 to 36 tons 

per year. These emissions were subtracted from the baseline emissions, 

resulting in an adjusted baseline of 745 to 624 tons per year. A 35% reduction of 

the baseline emissions would result in achievable emission reductions of 261 to 

218 tons per year, and average daily emissions of 0.72 to 0.6 tons per day. This 

level of emissions reduction is consistent with the District’s attainment plans for 

the source category and is reasonable given the cost of control estimates and 

degree of uncertainty about potential impact on product quality.

B. Benefits to Air Quality

Emissions controls for this source category have yet to be established, 

worldwide. Technical uncertainties and cost effectiveness of controlling wine 

fermentation emissions remain unresolved. Structuring Draft Rule 4694, as a 

market-based rule provides winery operators flexibility to develop cost effective 

fermentation emissions control technology, over time, while achieving 

commitments contained in the District’s Ozone and PM Plans for emission 

reductions from this source category. Achieving the Plan commitments satisfies 

the District’s committment in the SIP. The rule is structured to reduce at least the 

0.7 tpd commitment in the approved PM10 Plan and the percent reduction 

committed to in the yet to be approved 1-hr Ozone Plan. The current draft rule 

will provide environmental benefit by obtaining emission reductions sooner than 

would be probable with adoption of a conventional command and control rule. 

The concept is consistent with US EPA guidance for control measures 
incorporating a market-based approach. 

If the draft rule were adopted December 2005, operators would demonstrate 

compliance beginning July 1, 2007. This would be accomplished by installing 

fermentation controls, controlling other emission sources, or paying into a District 

managed Air Quality Impact Mitigation Fund, that would be used by the District to 

obtain surplus emission reductions. If structured as a conventional command 

and control rule, the only option is to install controls on wine fermentation tanks. 

Given that the technology has not been applied to wine fermentation substantial 

time will be required for design and engineering. The likely timeline for installing 

controls on fermentation tanks would be six months planning, 18 months 

engineering, and 12 months construction. Given the seasonal nature of wine 

fermentation, benefits to air quality would not be realized until the 2010 

fermentation season. 

Structuring Rule 4694 consistent with a market-based approach will obtain 

reductions from emission sources that would not be readily controlled through 

traditional regulation. As previously stated, the current draft rule would allow 

operators to mitigate fermentation emissions by obtaining surplus emission 

reductions. Surplus emissions are emissions that have not been committed to or 

required by any local, state or federal permit, rule, regulation, law, ordinance, or 

an approved air quality plan. Thus, surplus reductions would come from sources 

not readily controlled by traditional regulations.

Structuring Rule 4694 consistent with a market-based approach would achieve 

emission reductions in excess of the required 35% reduction in baseline 

emissions. Emission reductions occurring offsite require an offset ratio of 1.2 

tons. This is a 20% premium for operators employing this provision. The 

uncertainty of the grape harvest is expected to result in emission reductions 

exceeding the 35% reduction requirement. The volume of wine fermentation that 

occurs within a given year is intrinsically linked to the grape harvest. Operators 

cannot accurately predict their actual emissions. To guard against potential 

determination of violation of the rule, and to simply the process of demonstrating 

compliance, with the 35% VOC emission reduction requirement, operators are 

expected to obtain emission reductions in excess to the rule requirements. The 

three-year compliance plan provision and annual compliance demonstration will 

enable the District to quantify these additional reductions.
C. Localized Impact of Emissions Shifts

Proposed Rule 4694 would allow winery operators to mitigate fermentation 

emissions by controlling emission sources located off the winery premises. To 

evaluate the potential localized health impacts associated with shifting emission 

reductions to offsite locations, District staff prepared a health risk assessment for 

each of the thirteen wineries currently undergoing the District’s permitting 

process. These wineries are the 13 largest wineries in the District. The risk 

assessment was prepared in accordance with the requirements of AB 2588, Air 

Toxic Hot Spots Information and Assessment Act of 1987. This HRA was 

conducted in accordance with the Office of Environmental Health Hazard 

Assessment (OEHHA) Health Risk Assessment Guidelines.

Emissions of toxic air contaminants from wine fermentation were identified and 

the resulting potential ambient air concentrations calculated. These 

concentrations have been used to arrive at conservative estimates of increase 

carcinogenic risk that might occur as a result of continuous exposure over a 70-

year lifetime. In a similar fashion, concentrations of compounds with a noncarcinogenic adverse health effects were used to calculate the hazard indices 

(ratio of expected exposure to an acceptable exposure). A hazard index less 

than 1.0 is not considered to be a significant health risk. A hazard index greater 

than 1.0 is considered to be a significant risk and would result in the District 

consulting with the Office of Environmental Health Hazard Assessment (OEHHA) 

to determine the significance on a case-by-case basis. 

Based on the results from the health risk assessment, it is not expected that any 

winery operating in the San Joaquin Valley would pose a significant risk. (A 

significant risk is considered to be a risk of 10 in one million cancer case or 

greater than or equal to one for either the acute or chronic hazard index.) Details 

of the analysis are presented in Appendix E.

D. Sources of Alternative Emissions

Proposed Rule 4694 would allow operators to mitigate fermentation emissions by 

controlling alternative emission sources. A list of potential alternative emission 

sources, including the respective project life, cost per project, and annual 

emission reductions is presented in Appendix G. It should be noted that project 

life, as presented in Table-1 and Table-2, is the basis for determining cost 

effectiveness only, and does not necessarily reflect the actual life of an emission 

reduction. Emission reductions from stationary sources are expected to be 

permanent. The District will assess emission reduction durations at the time of 

project review. 
VII. PROPOSED RULE 4694

A. Summary of Proposed Rule

The proposed rule is summarized in the following paragraphs.

Section 1.0 Purpose

The purpose of the rule is to reduce emissions of volatile organic compounds 

(VOC) from the fermentation and bulk storage of wine, or achieve equivalent 

emission reductions from alternative emission sources.

Section 2.0 Applicability

The rule would apply to all wineries operating in the District.

Section 3.0 Definitions

Definitions of terms having specific application to the rule are provided.

Section 4.0 Exemptions

Wineries producing less than 10 tons VOC emissions from wine fermentation 

would be exempt from the rule’s control requirements. Wineries seeking 

exemption would be limited by their District Permit-to-Operate to emitting less 

than 10 tons VOC emissions from wine fermentation per year, and would be 

subject to the rule’s recordkeeping requirements and applicable District reporting 

requirements. 

As stated in Appendix B, Emissions Reduction Analysis, the 10-ton exemption 

threshold would exempt 91 of the 109 wineries operating in the District. The 

remaining 18 wineries, subject to the emission reduction requirements of the rule, 

account for about 95% of the wine fermentation emissions occurring in the 

District. Thus, the exemption results in an adjusted annual emissions baseline of 

624 to 745 tons of VOC emissions from wine fermentation.

Section 5.0 VOC Control Requirements 

Section 5.1 Fermentation Tank VOC Emission Control Requirements

Wineries subject to the rule’s emission control provisions would be required to 

reduce their baseline VOC emissions from wine fermentation by 35 percent, 

annually.

Wine fermentation is dependent upon the grape harvest and fluctuates 

seasonally. Therefore, the baseline fermentation emissions would be 
established as the average uncontrolled fermentation emissions occurring at the 

winery during the previous three-year period. New wineries may not have three 

years of historical production data. For wineries lacking three years of 

fermentation data, the baseline would be established using available 

fermentation data. Given the seasonal fluctuation in wine fermentation, and that 

an average may not reflect previous or planned growth, operators could 

voluntarily establish a baseline higher than the three-year average, but not higher 

than the emission limits established in the facilities Permit to Operate. The 

baseline would be reestablished every three years. 

Operators could comply with the fermentation emissions reduction requirement 

using any combination of the following methods:

Control VOC Emissions From Wine Fermentation

Operators may install VOC controls on their fermentation tank. The rule would 

not specify the control technology to be used in reducing fermentation emissions. 

Nor would the rule specify the percent capture and control efficiency of the VOC 

control system. This provides operators flexibility to pursue emissions reductions 

that are optimum for their operation, in terms of process operations and cost 

effectiveness. Emission reductions would be made enforceable as conditions of 

the emissions source Permit To Operate. Failure to operate the VOC control 

system consistent with the source’s Permit To Operate would be an enforceable 

violation.

Mitigate Fermentation VOC Emissions by Controlling Other Emissions 

Sources

Operators could mitigate their fermentation emissions by obtaining surplus 

emission reductions from other emission sources operating in the District. 

Surplus emissions would be emissions that have not been committed to or 

required by any local, state or federal permit, rule, regulation, law, ordinance, or 

an approved air quality plan.

Surplus emissions could be obtained from any VOC or NOx emissions source. If 

the emissions source operates exclusively on the winery premises, the emissions 

reduction ratio would be 1.0 ton of pollutant controlled per 1.0 ton of VOC emitted 

from wine fermentation. If the emissions source does not operate exclusively on 

the winery premises, the emissions reduction ratio would be 1.2 ton of pollutant 

controlled per 1.0 ton of VOC emitted from wine fermentation. 

If the emission units were subject to District Rule 2010 (Permits Required), the 

reduction in surplus emissions would be made enforceable as a condition of the 

source’s Permit to Operate. Failure to operate the VOC control system 

consistent with the source’s Permit to Operate would be an enforceable violation. 

If the emissions units were not subject to District Rule 2010, the reduction in 

surplus emissions would be made enforceable by a legally binding contract 
between the winery operator, the emissions source provider, and the District. 

Failure to operate the VOC control system consistent with the contract would be 

considered an enforceable violation.

Operators would be required to obtain surplus reductions having a minimum 

duration of three years in aggregate. Surplus emission reductions with duration 

greater than three years would be allowed for the life of the emissions reduction. 

For fermentation tanks subject to emission controls from New Source Review 

requirements, the maximum allowable emission reduction credit would be the 

lesser of either the actual emission reduction generated by the NSR review 

control, or 35% of the uncontrolled emissions.

Pay the District to Obtain Emissions mitigations for the Winery

Operators may comply by paying the District a fee that would be used by the 

District to obtain surplus emission reductions. The fee would be of an amount 

sufficient to cover the District’s cost of obtaining emission reductions that would 

last at least three years in aggregate. In addition, operators would pay the 

District an administrative fee, covering the District’s cost of operating the 

mitigation program.

For the compliance period beginning January 1, 2007, the mitigation fee would 

be established at a rate of $11,788 per ton. The administrative fee would be 

established at 4% of the mitigation fee. The mitigation fee and administrative fee 

structures would be adjusted periodically to cover the District’s actual cost of 

obtaining emission reductions. 

Fermentation Emissions Baseline

Each winery’s baseline would be established as the average of the previous 

three years of fermentation VOC emissions. The baseline would be 

reestablished every three years, based on the previous three years of operation. 

Wineries with less than three years historical fermentation data would establish 

their baseline as the average emissions calculated using the available data. 

Operators would also have the option of selecting a baseline higher than the 

three-year average, but less than the emissions limits established in the facility’s 

Permit to Operate.

Section 5.1 Storage Tank Emissions Control Requirements

Storage tanks having an internal volume of 5,000 gallons of greater would be 

required to be equipped and operated with a pressure-vacuum relief valve and 

the temperature of the stored wine would be maintained at or below 75o

Fahrenheit. Pressure-vacuum relief valves would have to operate within 10% of 

the working pressure of the tank and operate in accordance with the 

manufacture’s instructions. Temperature of the stored wine would be recorded 

weekly, and operators would have 60 days after fermentation to achieve the 
storage temperature.

Section 6.0 Administrative Requirements

This section would establish the administrative framework for complying with the 

rule.

Section 6.1 Three-year Compliance Plan

Beginning July 1, 2006 and every three years thereafter, operators would submit 

a plan to the District detailing how they will comply with the rule. Key elements of 

the plan include the results and supporting documentation for the following 

details: a) Baseline fermentation emissions, b) required annual emission 

reductions, c) annual fermentation emission reductions to be achieved, d) annual 

alternative emission reductions to be achieved, e) emission offsets, if applicable, 

and f) annual emission reductions to be acquired by payment into a District 

operated air quality impact mitigation fund. The plan would identify each 

emissions unit, and the planned reductions. The plan would include any 

applicable contracts for emission reductions.

Section 6.2 Three-year Compliance Plan Verification

By no later than July 1, 2007 and every three years thereafter, operators would 

submit to the District verification that they have taken appropriate actions to 

implement the emission reduction measures identified in their Three-year 

Compliance Plan. 

Section 6.3 Annual Compliance Plan

Commencing no later than February 1, 2008, and annually thereafter, operators 

shall submit to the District an Annual Compliance Plan Demonstration that shows 

compliance with the applicable requirements. Two compliance scenarios are 

possible:

1 If annual wine production resulted in fermentation emission less than or equal 

to the baseline emissions, the operator demonstrates that they at least 

achieved the emission reduction stated in their plan. 

2 If annual wine production resulted in fermentation emissions exceeding the 

baseline emissions, the operator demonstrates that in addition to obtaining 

reductions equal to 35% of the baseline emissions, they also obtained a 35% 

reduction in all fermentation emissions above the baseline. Operators who 

exceeded their baseline emissions have until April 1, of that year to obtain 

reductions necessary to offset the excess emission reductions. 

Operators can obtain the additional reductions from operators who achieve 
emission reductions above their emission reduction requirement, install additional 

emission controls, or make additional payment to the District’s Air Quality Impact 

Mitigation Fund. Operators failing to implement their compliance plan, or failing 

to obtain the required emission reductions would be found to be in violation of the 

rule requirements.

Section 6.4 Monitoring and Recordkeeping

The rule would require operators to keep records sufficient to demonstrate that 

the required emission reductions were achieved. Records would include all 

contracts executed in acquiring offsite emissions reductions, all records 

documenting performance of the emissions control systems, records used to 

calculate emissions from each batch of wine fermented at the facility, and 

storage temperatures of bulk wine. Operators claiming exemption would be 

required to maintain annual production records of total gallons of red wine and 

white wine fermented at the winery.

Section 6.5 Air Quality Impact Mitigation Fund Fee Review

The section requires that the fees paid to the fund be sufficient to cover the 

District’s cost of obtaining the emission reductions, plus the District’s cost of 

administering the program. Fees structures would be evaluated annually. An 

analysis shall be performed that details the cost effectiveness of the projects 

funded to date; the rule effectiveness of achieving the required emission 

reductions to date; the availability of off-site emission reduction project; and the 

cost effectiveness of those projects. The APCO shall provide a draft revised cost 

effectiveness based on the analysis. The process shall include at least one 

public workshop.

Section 6.6 Test Methods

This section establishes test methods to be used to determine emissions and 

emission reductions. Emission units identified in District prohibitory rules would 

comply with test methods specified in the applicable rule. Emission units not 

currently identified in a District rule would be required to use methods approved 

by the District, US EPA and ARB. The section includes methods specific to VOC 

control and specific to NOx control.

Section 6.7 Compliance Testing

This section is similar to Section 6.6. If the emissions unit is identified in an 

existing District prohibitory rule, operators comply with the testing requirements 

specified in the applicable rule. If the emissions unit is not identified in an 

existing District rule, the operator would comply with testing requirement 

approved by the APCO, US EPA, and ARB.
Section 7.0 Compliance Schedule

The compliance schedule is presented in Table-1 of Draft Rule 4694. In brief:

1 Operators would have until July 1, 2006 to submit their initial compliance plan. 

Baseline emissions would be established using fermentation production from 

the years, 2003, 2004, and 2005. The initial compliance plan would be for the 

period of 2007 through 2010. Baseline emissions and a new compliance plan 

would be reestablished every three years thereafter. 

2 Commencing July 1, 2007, and every three years thereafter, operators would 

verify that the elements of their compliance plan had been implemented. 

3 Commencing February 1, 2008, and annually thereafter, operators would 

demonstrate compliance with the rule. 

4 Commencing April 1, 2008, and annually thereafter, operators whose 

production resulted in emissions above the baseline, would demonstrate that 

they obtained the required 35% reduction in baseline emissions, plus reduced 

emissions from their excess production by 35%.

B. Determination of Air Quality Impact Fund Fee Structure

Section 6.1.5.3 provisions would allow operators to mitigate their fermentation 

emissions by payment into the District’s Air Quality Impact Mitigation Fund. The 

fund would be used by the District to obtain emission reductions in behalf of fund 

contributors. As of January 1, 2006 the fund rate is established at $11,778 per 

ton and the District’s administrative fee is established at 4%.

The initial fund rate is based on the Carl Moyer proposed VAVR guidelines to 

accelerate removal of older, higher emitting vehicles from the road. The District 

may pursue other stationary or mobile source reduction projects that would have 

different cost effectiveness values. The cost per vehicle estimate presented 

here, however, provides reasonable assurance that funding will be sufficient to 

obtain the necessary reductions. The District’s assumptions and methodology 

for establishing the current fund fee rate is presented below.

Assumptions

1 Emission reduction factor: 0.04 tons of combined VOC and NOx emissions 

per vehicle per year.

The emission factor is calculated as a weighted average based on the 

model year distribution for 103 cars removed by the Bay Area Air Quality 

Management District (BAAQMD) vehicle buy back program and ARB’s 

emission factors for the included model years.

2 Emission reduction duration: 3 years 
Emission reductions for retired vehicles have a lifetime of only three years. 

The District assumes that a high emitting vehicle would have been 

replaced through natural attrition within a three-year period.

3 Cost per car = $1,333

Costs for operating voluntary vehicle removal programs vary depending 

on several factors, i.e., cash incentives paid to vehicle owners and cost of 

vehicle retirement (crushing/scrapping). This estimate assumes an 

incentive of $1,100 paid to the vehicle owner and a cost of $233 for 

vehicle dismantling.

4 Capitalization factor = 0.3535

Assumes cost of retirement is amortized for three years at 3% interest

5 Number of retired vehicles: 100 

Used for illustrative purposes only, actual number of vehicles retired will 

depend on public response to the program.

Calculations: 

Note: the $11,778/ton fee presented in the staff report was derived using 

spreadsheets, the values of which are truncated here and presented for 

illustrative purposes only.

1. Annual Emission Reductions (AER)

AER = No.Vehicles X EF

Where,

AER = Annual emission reductions in tons

No. Vehicles = Number of vehicles removed from service

EF = Annual emission reduction per vehicle removed from service

vehicle

0.04 tons/year AER =100 Vehicles X

AER = 4 tons per year

2. Total Emission Reductions (TER)

3 years

Year

4 tons TER = X

TER = 12 tons

3. Annualized Cost of Vehicle Retirement
0.3535

vehicle

$1,333 Annualized Cost = 100 Vehicles X X

Annualized Cost = $47,122

4. Cost Effectiveness

4 tons/year

$47,122/year Cost Effec tiveness =

Cost Effectiveness = $11,778/ton of air pollution reduced
Example Calculation of AQIMF Fee Payment

The following is an example of how operators would calculate payment into the 

AQIMF.

Assumptions

1 Winery Baseline Fermentation Emissions = 100 tons per year

2 Fermentation Emission Reductions = 10 tons per year

3 Certified Emission Reductions = 15 tons per year

4 Compliance plan duration = 3 years

5 Fund Fee Rate = $11,778

6 Administrative Fee = 4%

7 Administrative Fee Factor = 1.04

Calculations

Required Annual Emission Reductions = 35% of Baseline Fermentation

Emissions

RAER = 35% x 100 tons/year = 35 tons/year

DOER = RAER – FER – CER

DOER = 35 tons/year – 10 tons/year – 15 tons/year = 5 tons/year

DOER for compliance period = 5 tons/year x 3 years

DOER for compliance period = 15 tons

AQIMF Payment = DOER x Fund Fee Rate x Administrative Fee Factor

AQIMF payment = 15 tons x $11,778/ton x 1.04

AQIMF payment = $183,737

VIII. RULE DEVELOPMENT PROCESS

District staff conducted a public scoping meeting on January 26, 2004. At the 

scoping meeting, District staff presented the objectives of the proposed 

rulemaking project, and solicited comments and suggestions, which were then 

used to develop the draft rule and staff report. District staff conducted the first 

series of workshops on October 21, and 27, 2004; staff presented the first draft of 

Rule 4694 and received public comment.

Based on public comments and additional information developed after the first 

workshop, District staff revised the draft rule and staff report. A second 

workshop was conducted on June 28, 2005. On July 14, 2005, District staff 

conducted an industry focus group meeting to gather information supporting 
assessment of the socioeconomic impact the draft rule. Following the second 

workshop and the socioeconomic focus group, public comments provided by the

Wine Institute indicated that the technical issues associated with controlling wine 

fermentation emissions were still unresolved. The Wine Institute also submitted 

a copy of a socioeconomic analysis prepared for the Wine Institute by MKF 

Group LLP. The report prepared by MKF Group used cost of control data 

prepared by Eichleay Engineers for the Wine Institute. District staff subsequently 

met with representatives from the wine industry to better understand the 

technical issues and discuss our cost effectiveness analysis. Consistent with the 

District’s rule development procedures, the District’s consultant prepared an 

independent socioeconomic analysis of the draft rule. 

In proposing the current draft rule, District staff considered all public comments, 

all reports prepared by consultants to the District, and staff’s technical findings 

and analyses. Staff believes that it is technically feasible to control wine 

fermentation emissions in a cost effective manner, without detriment to product 

quality. However, the wine industry needs time to gain the experience necessary 

to incorporate fermentation emission controls into their wine production 

processes. District has restructured Draft Rule 4694 to incorporate a marketbased approach that achieves emission reductions consistent with the plan, 

expedites obtaining emission reductions from wine fermentation, and provides 

the wine industry time to develop expertise in controlling fermentation emissions 

without devaluating product quality.

The third workshop was conducted October 11, 2005. After close of comment 

period, the draft rule and staff report were revised, as appropriate. Proposed 

Rule 4694 will be submitted to the District Governing Board for Receive and File 

during their November 17, 2005 meeting. Public hearing for consideration of 

adoption of the proposed rule by the District Governing Board is planned for 

December 15, 2005.

Staff has had numerous discussions with representatives from the wine industry, 

U.S. EPA, and environmental organizations throughout the rule development 

process. The market-based format of the rule has resulted in questions about 

equivalency with conventional command and control rules. Because of the 

required adoption schedule, it has not been possible to completely resolve some 

issues at this time. Staff is committed to resolving the remaining issues during 

the implementation phase, through education and continued dialogue with all 

interested parties. Major outstanding issues pertain to defining RACT for the 

source category and showing compliance with the EPA’s EIP guidance 

document.
IX. COST EFFECTIVENESS

As presented in Appendix C, Cost Effectiveness Analysis, of this draft staff 

report, three cost effectiveness scenarios were considered: 

1 Scenario-1, estimates average cost effectiveness for controlling VOC 

emissions from red wine at $27,000/ton-VOC reduced and average cost 

effectiveness for controlling VOC emissions from white wine at $82,000/tonVOC reduced. 

2 Scenario-2 estimates cost effectiveness for controlling VOC emissions from 

red wine fermentation at $120,479/ton-VOC reduced. 

3 Scenario-3 estimates average cost effectiveness for controlling VOC 

emissions from red wine fermentation ranges from $42,200/ton-VOC to 

$52,900/ton-VOC reduced. 

There are no known examples of the application of VOC emission controls to 

wine fermentation, making accurate determination of cost effectiveness difficult. 

Scenario-1 likely understates the cost of control because it assumes that tanks 

process the maximum number of batches possible, which is seldom achieved in 

practice. Senario-2 likely overstates the cost of control because the estimate 

includes significant site-specific costs, and the control system design is not 

optimized. Scenario-3 corrects for Scenario-II assumptions. Staff considers 

Scenario-III to represent the likely cost of controlling fermentation emissions.

As presented in Section VI, of this staff report, the rule has been revised to 

incorporate a market-based approach, which provides operators flexibility to 

chose either to install VOC controls on their fermentation tanks; mitigate their 

fermentation emissions by controlling surplus emissions, or other pay into a 

District Air Quality Impact Mitigation Fund (AQIMF). Monies paid to the AQIMF 

would be used by the District to secure emission reduction equal to or greater 

than operator’s emissions reduction obligation. Given that the initial AQIMF fee 

rate would be established at $11,778 per ton, it is reasonable to expect that an 

operator will not pursue control options more expensive than the AQIMF fee rate. 

Thus, the current cost of control is considered $11,778 per ton of VOC reduced. 

Cost of obtaining surplus emissions could increase overtime, resulting in higher 

operator costs, which should provide an incentive for the industry to control VOC 

emissions from wine fermentation.

X. SOCIOECONOMIC ANALYSIS

Pursuant to state law, District staff is required to perform an assessment of the 

socioeconomic impacts prior to the adoption, amendment, or repeal of a rule that 

will have significant air quality benefits or that will strengthen emission limitations. 
As a part of the District’s socioeconomic analysis process, on July 14, 2005, 

District staff conducted an industry focus group meeting to gather information 

supporting assessment of the socioeconomic impact the draft rule. 

Given the wide range in estimated costs of control, and the lack of an inventory 

of fermenter tanks, by size category and their associated emissions, the District’s 

socioeconomic consultant was directed to evaluate three cost scenarios. 

Scenario-1 was for control costs ranging from $10,000 to $20,000 per ton VOC 

reduced. Scenario-2 was for control costs ranging from $40,000 to $50,000 per 

ton VOC reduced. Scenario-3 was for control costs ranging from $100,000 to 

$125,000 per ton VOC reduced. The socioeconomic report appears in Appendix 

D and was presented at the final workshop on October 11, 2005. In brief, the 

cost of compliance associated with the market-based approach presented in the 

current draft rule, expressed as a percent of affected wineries’ profit is estimated 

at about 2.6%. This level is well below the 10% significance threshold used to 

gauge a rule’s potential socioeconomic impact on the District’s economy.

XI. ENVIRONMENTAL IMPACTS 

Proposed Rule 4694 has undergone environmental review in accordance with 

the requirements of the California Environmental Quality Act. A proposed 

negative declaration has been issued by the District and made available for 

public review and comment. The public review period ended on November 2, 

2005. No Comments were received.

XII. Rule Consistency Analysis

Pursuant to California Health & Safety Code Section 40727.2, District staff has 

determined that Draft Rule 4694 is in harmony with, and not in conflict with or 

contradictory to, existing statutes, court decisions, or state or federal regulations 

that apply to the same type of equipment or source category. The analysis is 

presented in Appendix F.

XIII. REFERENCES

Akton Associates, A Demonstration Program, Ethanol Emissions Control from 

Wine Fermentation Tanks Utilizing Carbon Adsorption Technology, 1990

Art Caput, Wine Institute, Letter to the District, July 18, 2005

Art Caputi, The Wine Institute; Bob Calvin, Canandaigua Winery, Telephone 

Conversations with Daniel Barber, San Joaquin Valley Air Pollution Control 

District, 2004
Bateman, David, U.S. Department of the Treasury, Alcohol and Tobacco Tax 

Bureau, (2004) Telephone Conversation with Daniel Barber, Ph.D., San Joaquin 

Valley Air Pollution Control District.

California Air Resources Board, Emissions Inventory Procedural Manual, Sec. 

5.1, Updated May, 2004

California Department of Alcoholic Beverage Control, Licenses Database, 2002

Eichleay Engineers, Fermenter VOC Emissions Control Cost Estimate, Eichleay 

Project No. 30892 & 303913, June 30, 2005

Robert P. Koch, Wine Institute, Letter to the District, November 22, 2004.

MKF Group LLP, Socio-Economic Assessment of Proposed Rule 4694, July 29, 

2005.

Staff discussions with Bob Calvin of Canandaigua Winery, August 2005.

The Wine Institute, correspondence with District staff, August 2005

The Wine Institute, Survey of Fermenter Usage Patterns for Nine Large Wineries 

in the Central Valley. June 2004.

U.S. Department of the Treasury, Alcohol and Tobacco Tax Bureau, 2002 

Alcohol Production Statistics