SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 1 Final Staff Report with Appendices

For Revised Proposed Rule 4694

APPENDIX B

Emissions Reduction Analysis for

Rule 4694 (Wine Fermentation & Storage Tanks)

December 15, 2005
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 2 Final Staff Report with Appendices 

For Proposed Rule 4694

I. SUMMARY

This appendix details the emission reduction analysis for Draft Rule 4694. The detailed 

calculations shown later produced the following results.

• Total volatile organic compound (VOC) emissions in 2002, from wine 

fermentation, are estimated to range from 660 to 788 tons per year. Proposed 

exemptions in Draft Rule 4694 would result in 624 to 745 tons of the total VOC 

emissions being subject to control requirements. 

• Draft VOC control requirements would require operators to reduce their baseline 

fermentation VOC emissions by 35%, annually. This would equate to annual 

emission reductions of 218 to 261 tons, for a daily reduction of 0.6 to 0.72 tons 

per day.

• As presented in the Extreme Ozone Attainment Demonstration Plan, October 

2004, the 2008 planning baseline emissions from wineries is 2.1 tons per day, 

and planned emission reductions for Rule 4694 are 0.7 tons per day, for a 

planned emission reduction of 33%.

II. INTRODUCTION

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

Joaquin Valley Air Basin (SJVAB)1. The majority of wine production in the SJVAB 

occurs at large wineries, each with annual wine production capacities of tens of millions 

of gallons. In 2002, 18 wineries had annual permitted production volumes ranging from 

5 million to greater than 50 million gallons 2 each. These wineries accounted for 95% of 

the District’s VOC 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 per winery and 58% of the wineries had annual production volumes of 

less than 2,000 gallons.

Red and white wines differ significantly in their respective production processes, 

affecting fermenter use and associated VOC emissions. Red wines are fermented at 

high temperatures (70 o F to 80o F), in contact with skins, seeds, and pulp. Fermentation 

of red wine typically occurs within three to four days. White wines are fermented at low 

temperatures (45o F to 65o F), with little contact with skins, seeds, and pulp. 

Fermentation of white wines occurs over a period of seven to ten days. The resulting 

emissions factor for red wines (6.2 lb VOC/1000 gallons) is almost 2.5 times greater 

than emission factors for white wine (2.5 lb VOC/1000 gallons) and fermenter 

throughput for red wine is about twice that of equal sized white wine fermenters.

This report presents the estimated annual VOC emissions baseline and anticipated 

emission reductions associated with implementing the exemptions proposed in section 

 

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

2 California Department of Alcoholic Beverage Control, Licenses Database, 2002
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 3 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

4.0 and the emission reduction requirements presented in Section 5.0. Methods used 

to calculate emission reductions, and associated assumptions are discussed.

III. BACKGROUND

In commercial wineries, fermentation commonly occurs in fixed-roof steel tanks 

(fermenters) by inoculation of must3 with yeast. Fermenters in use at large wineries 

operating in the SJVAB range in size from about 25,000 gallons to 600,000 gallons. 

Most fermenters are equipped with a manhole at the top (approximately three feet in 

diameter) that is open during fermentation. Emissions are vented through the manhole 

without the aid of mechanical equipment (e.g., fans).

Fermentation temperature affects the characteristics of the wine. Large wineries control 

tank temperatures through use of cooling jackets and/or heat exchangers (i.e., wine is 

re-circulated from the bottom of the tank through a heat exchanger, and back into the 

tank). Thermostats and computerized controls can maintain temperatures of must and 

wine within one or two degrees. Red wines are normally fermented at relatively high 

temperatures (70 o F to 80o F), over a period of three to four days. White wines are 

typically fermented at lower temperatures (45o F to 65o F), and therefore fermentation 

takes longer, about seven to ten days.

A key distinction in the production of red or white wines is the point in the process that 

pressing, the separation of the juice from the skins, pulp and seeds, occurs. With very 

few exceptions, grapes have clear juice; the color in wine comes from pigmentation 

contained in the skins. The longer the contact between skins and juice, the more color 

is extracted from the skins. To make most white wines, winemakers press the juice 

from the grapes before fermentation, separating the stems, skins, pips and pulp from 

the juice. The juice is then sent to a fermenter where the winemaker initiates 

fermentation by inoculating the must with yeast. In one variation, as in the production of 

blush wines, after crushing the grapes go into a settling tank. While in the settling tank 

the grapes are chilled and may sit for up to 24 hours of skin contact before being 

pressed and then fermented. 

To make most red wines, winemakers press the juice from the grapes after 

fermentation. Crushed grapes are pumped into a fermenter and the winemaker initiates 

fermentation by inoculating the must with yeast. During fermentation, the skins and 

solids in the must will float to the top of the liquid, forming a solid cap. This leaves only 

the portion of juice underneath the cap in contact with the skins. To insure more color 

extraction wine makers use a variety of methods to enhance contact between the cap 

and juice. After enough color and tannin are extracted, the free run liquid is pumped to 

another tank and the must sent to a press where the entrained liquid is extracted. The 

solids are discarded and the pressed wine may be added back to the free run or 

 

3 Must is any unfermented juice or mixture of juice, pulp, skins, and seeds prepared from grapes or other fruit.
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 4 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

otherwise processed. Depending on the style of red wine being produced, pressing 

may occur before fermentation is complete. After transfer and pressing, the 

temperature of the wine is lowered to below 60o F. Depending on the desired properties 

of the wine, the winemaker may allow fermentation to continue until there is no residual 

sugar, or stop the process. After fermentation, wine undergoes several additional 

processing steps to achieve the desired characteristics. Additional processing may 

include clarification, blending, and aging.

Emissions Characterization

Wine production is predominantly a seasonal event, coinciding with the grape harvest 

season. Within the San Joaquin Valley, about 97% of wine production occurs in the 

months of August through December. Fermentation is at its peak during September 

through October. About 74% of wine fermentation occurs within those months. During 

the peak of the grape harvest, wineries processing millions of gallons of wine annually 

will operate 24 hours per day, seven days of the week. For a given fermenter, it is 

possible to run one fermentation batch after another throughout the harvest season. 

Between each batch, the fermenter is sterilized in accordance with U.S. Food and Drug 

Administration requirements and readied for a new fermentation batch. 

Seasonal throughput for a single fermenter varies from year to year and winery to 

winery. Assuming a fermentation season of 60 to 90 days, and a batch time of 5 days 

for red wine and 10 days for white wine, theoretical throughput for a single fermenter 

could be 12 to 18 batches for red wine and six to nine batches for white wine. 

According to the Wine Institute4 5, this theoretical throughput is seldom achieved. The 

Wine Institute estimates that over 85% of wineries process 6 batches or less per tank, 

and 67% process 4 batches or less6. According to a Wine Institute survey of nine large 

wineries operating in the District, the maximum number of batches for red and white 

wine was 18 and 8 batches respectively. 

Quantitative characterizations of fermentation emissions will vary from winery to winery 

and within a winery. Emissions produced during fermentation depend upon process 

parameters, such as sugar content of the must, degree of temperature control, and type 

of wine being produced. During the fermentation process, glucose and fructose in must 

undergo reaction by yeast activity and produce ethanol and carbon dioxide (CO2). The 

amount of ethanol emitted to the atmosphere depends on the fermentation temperature 

and duration, the sugar content of the must, and the volume of must. Because of their 

higher fermentation temperatures, shorter fermentation periods, and the presence of the 

cap, fermentation emissions per batch are higher for red wines than white wines. 

 

4 Art Caputi, The Wine Institute; Letter to the District, July 18, 2005

5

The Wine Institute, Survey of Fermenter Usage Patters for Nine Large Wineries in the Central Valley, June 

2004

6 Robert P. Koch, Wine Institute, Letter to the District, July 19, 2005
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 5 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

Concomitantly, VOC concentrations and airflow rates for red wines reach higher peak 

values and vary more significantly than those encountered in white wine fermentation.

Ethanol is the most abundant VOC emitted during wine production. Other compounds 

emitted during fermentation include acetaldehyde, isoamyl alcohol, isobutyl alcohol, 

methanol, n-propanol, and hydrogen sulfide. Emissions of these species are 

substantially less than emitted ethanol, however it is worth noting that acetaldehyde is 

classified as hazardous air pollutant.

A general depiction of emissions generation over the course of a fermentation batch is 

shown in Figure-1. It has been noted, “the conditions of this fermentation are for 

illustrative purposes and are not typical of most wine fermentation” (Williams, 1983, p. 

1606). However, basic characteristics of the diagram have been supported by test data 

(Fielder and Bumala, 1982; Todd et al., 1988, 1990): i.e., emissions and air flow rates 

vary significantly over the course of a fermentation batch, reaching a peak in the middle 

of the batch and then declining towards the end of the batch.

Figure-1. Depiction of emissions generation over the course of an isothermal fermentation at 21.1oC = 70oF, as 

predicted by modeling. Figure is from Heredia (1993), citing Williams and Boulton (1983). CO2 evolution rate and 

ethanol emission rates are per liter of liquid fermented; airflow rates are proportional to CO2 evolution.

Another source of fugitive emissions is working loses associated with bulk wine storage. 

After fermentation, 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 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 6 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

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.

Emission Factors

A. Wine Fermentation

On January 26, 2004, District staff published a Preliminary Draft Staff Report and 

conducted a Scoping Meeting to present the revised emissions inventory and to solicit 

public comment on the rule development project. These efforts identified concerns that 

the emissions factors recommended by STI overstated the emissions inventory. STI 

recommended using emissions factors of 10-lb ethanol/1000 gallons of red wine 

fermented and 3-lb ethanol/1000 gallons white wine fermented. These emission factors 

were higher than emissions factors presented in a US EPA guidance document (AP-42 

Section 9.12.2). Emissions factors presented in AP-42 are 4.6 and 1.8 lb/1000 gallons 

for red and white wines respectively.

In developing their recommendations, STI reviewed the studies supporting the AP-42 

emission factors. STI identified several technical issues with the supporting studies, 

concluding that the data likely understated actual emissions. STI identified two studies 

that appeared technically sound; one study characterizes emissions from white wines, 

the other, emissions from red wines. The emissions factors proposed by STI were 

based on those two studies7.

District staff considered STI’s technical assessment of the supporting studies to be 

sound, but had reservations regarding the use of emissions factors based on such a 

limited data set. An alternative to AP-42 emission factors and those proposed by STI 

are emissions factors prepared by California Air Resources Board (CARB)8. The CARB 

emission factors are 6.2-lb/1000 gal and 2.5-lb/1000 gal for red and white wines 

respectively. These emissions factors are based on the stoichiometric model developed 

by professors Williams and Boulton, UC Davis. The foundation of the Williams and 

Boulton model is their thesis that ethanol loss occurs independent of fermentation rate; 

being driven by total sugar conversion and fermentation temperature. There are 

uncertainties in the model, and the model may understate emissions from red wine 

fermentations, however, the model has demonstrated relatively good correlation to 

known data sets.

District and CARB staff worked together to improve the methodology used to estimate 

the emissions inventory. Those discussions resulted in the following conclusions:

 

7

Sonoma Technology, Inc. (2003) Emissions Inventory Methodology – Wine Fermentation

8

Emissions Inventory Procedural Manual, Section 5.1, Air Resources Board, 1997
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 7 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

ß The emissions factors derived from the Williams and Boulton model are 

considered more representative than other known emission factors and will be 

used for emissions inventory purposes.

ß Wine fermentation activity data will be based on county level production data 

obtained from the U.S. Department of the Treasury, Alcohol and Tobacco Tax 

Bureau (TTB).

ß The percentage of red and white wine fermented will be based upon the 

California Grape Crush Report. The Crush Report contains crush data by grape 

type. Albeit, not all grapes crushed are used to produce wine, however, the 

relative difference between the amounts of grapes crushed is assumed to be 

maintained, whether used to produce wine or juice.

B. Bulk Storage

After fermentation, wine is transferred a number of times between storage tanks to 

perform various finishing 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, before 

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

finishing processes. The post-fermentation operations result in “working losses” from 

the storage tanks since they require draining and filling the tanks several times. 

Storage before 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. 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 were used, along with the assumption that water will behave ideally (a good 

assumption since the liquid phase is over 95% water on a molar basis). District staff 

calculates an emission factor for wine storage of 0.372 lb EtOH/1000 gal wine 

processed, based on a “typical” San Joaquin Valley wine storage scenario.

In 2002, 337,968,011 gallons of wine were fermented in the District. As illustrated in the 

following calculation, storing all of the 2002 wine fermentation in the District until bottled, 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 8 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

would result in annual storage emissions of 62.9 tons of VOC. Not all wine fermented in 

the District is bottled in the District, thus actual storage emissions are likely lower than 

estimated. 

62.9 ton

2,000lb

1 ton

1000 gal

0.372 lb ethanol 337,968,011gal x x =

According to District Permit To Operate application data, there are 4,086 tanks used for 

storing bulk wine in the District. 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 control9. As illustrated in the following calculations, 

average annual storage emissions per tank equal 30.8 lbs per year, or 0.08 lbs per day. 

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

constitute reasonable available control technology (RACT) for bulk wine storage tanks.

30.8lb/tank

4086 tanks

ton

2000 lb

year

62.9 tons

=

x

0.08 lb/tank/ye ar

365 day/year

30.8lb/tank

=

Alcohol Production and Emissions from Wine Fermentation

According to TTB production statistics, 338 million gallons of wine were fermented and 

almost 26 million gallons of brandy were produced in the SJVAB during 2002. 

Additionally, over 26 million gallons of distilled spirits were produced in the SJVAB 

(Table-1).

Table-1. Gallons of Alcoholic Beverage Produced in the San Joaquin Valley, 200210

County Wine Brandy Distilled Spirits

Fresno 103,725,752 19,491,659 15,260,235

Kern 10,393,071 3,896,020 602,040

Kings 0 0 0

Madera 29,482,509 393,045 4,205,903

Merced 67,423,044 2,065,043 2,803,643

San Joaquin 63,323,587 84 3,229,566

Stanislaus 51,752,044 0 0

Tulare 11,868,004 0 0

Totals 337,968,011 25,845,851 26,101,387

 

9

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

Barber, San Joaquin Valley Air Pollution Control District, 2004.

10 U.S. Department of the Treasury, Alcohol and Tobacco Tax Bureau 2002 Alcohol Production Statistics
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 9 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

Based on the 2002 Crush Report, approximately 58.5 percent of total grapes crushed 

were for red wine and approximately 41.5 percent were crushed for white wine. 

Applying Crush Report percentages to TTB production statistics shows 198 million 

gallons of red wine and 140 million gallons of white wine were produced in the District 

during 2002 (Table-2).

Table-2. Gallons of Red and White Wine Fermented in the San Joaquin Valley, 2002

County Red Wine White Wine

Fresno 60,679,565 43,046,187

Kern 6,079,947 4,313,124

Kings 0 0

Madera 17,247,268 12,235,241

Merced 39,442,481 27,980,563

San Joaquin 37,044,298 26,279,298

Stanislaus 30,274,946 21,477,098

Tulare 6,942,782 4,925,222

Totals 197,711,296 140,256,725

Applying the respective emissions factors (6.2-lb/1000 gal for red wine and 2.5-lb/1000 

gal for white wine) to District wine fermentation estimates results in an annual VOC 

emissions inventory for wine fermentation of 788 tons per year, Table-3.

Table-3. Annual Fermentation Emissions in the San Joaquin Valley, 2002

County

VOC Emissions from 

Red Wine (tons)

VOC Emissions from 

White Wine (tons)

Fresno 188 54

Kern 19 5

Kings 0 0

Madera 53 15

Merced 122 35

San Joaquin 115 33

Stanislaus 94 27

Tulare 22 6

Totals 613 175

Averaged over 365 days, annual daily VOC emissions are 2.2 tons per day. However, 

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

fermentation typically occurs over a 90 to 120-day period, resulting in peak seasonal 

daily averages of 8.8 to 6.6 tons VOC per day.
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 10 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

The Wine Institute has opined that actual emissions may be overstated because use of 

the Crush Report does not account for red grape varietals that could be fermented as 

blush wines11. Blush wines are fermented similar to white wines, and would have 

similar emissions. A Wine Institute survey of seven large wineries in the District shows 

that in 2004, about 38% of the wine produced in the Valley was red wine and 62% was 

white wine12. If these production statistics are representative of all wine production in 

the District, total annual VOC emissions from wine fermentation are estimated to be 660 

tons. The District is in the process of permitting wine fermentation and storage tanks. 

Emissions data gather through the permitting process will be used to update the 

emissions inventory. Where inclusion may improve clarity of this report, emissions 

estimates are presented as ranges, reflecting differences in Crush Report and Wine 

Institute statistics.

Temporal Variation

Although wine fermentation is seasonal, corresponding to the grape harvest, actual 

fermentation volumes reported by the TTB for 2002 shows that some fermentation 

occurs throughout the year (Table-4). While fermentation occurred year round in 2002, 

ninety-seven (97) percent occurred within the months of August through December. 

Fermentation peaked during September and October, accounting for 75 percent of the 

annual fermentation. The months in which the majority of wine is fermented coincides 

with the months when the SJVAB experiences the greatest exceedance of the NAAQS 

for one-hour ozone, in terms of both frequency and in magnitude.

Table-4. Monthly Distribution of Wine Fermentation Activity in the SJVAB 13

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Fermentation 

(Million Gallons) 1.5 2.2 .8 .6 1.8 1.7 1.8 22.1 125.2 126.7 34 20

Percentage 0.45 0.65 0.23 0.18 0.54 0.50 0.53 6.54 37.0537.4910.05 5.79

Wineries Operating in the SJVAB

The California Department of Alcoholic Beverage Control (ABC) maintains a database 

of all facilities permitted to produce alcoholic beverages in California. The ABC issues 

permits based on type of alcoholic beverage produced at the facility and estimated 

production volumes. According to the ABC permit database, 109 wineries were 

permitted to operate in the SJVAB during 2002, (Table-5). 

 

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

12 Art Caputi, The Wine Institute; Letter to the District, July 18, 2005

13 U.S. Department of the Treasury, Alcohol and Tobacco Tax Bureau 2002 alcohol production statistics
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 11 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

Table-5. Number of Wineries Permitted to Operate in the San Joaquin Valley, 2002

Permitted Production Volume (Million Gallons)

≤0.002 0.1 to 

0.2

1 to 

3

5 to 

9

12 to 

19

26 to 

37 ≥50 Total

Wineries per Category 63 13 15 5 7 3 3 109

Percent of Total 

Number of Wineries 58 12 14 5 6 3 3

Percent of Total 

Permitted Production 0.13 0.43 4.9 7.5 25.5 22.3 39.3

Of the 109 wineries operating in the SJVAB in 2002, 58% of the wineries had annual 

production volumes of less than 2,000 gallons and 70% of the wineries had annual 

production volumes of less than 200,000 gallons. Assuming VOC emissions resulting 

from wine fermentation are directly proportional to a facility’s permitted production 

volume, in 2002, 17% of the wineries (18 facilities) accounted for 95% of the District’s 

emissions from wine fermentation. Permitted production for those facilities ranged from 

5 million to 50 million gallons of wine.

Fermenter Usage

The District has begun the process of permitting wine fermentation and storage tanks 

but complete statistics of fermenters operating within the District are not available. 

Currently, the District has received permit application data from the thirteen largest 

wineries14. Of 4,534 tanks reported by these facilities, 3,076 are designated for use as 

fermenters. The majority of fermenters are made of coated mild-steel or stainless steel; 

about 6% of the fermenters contained in the District’s permit database were made of 

concrete. Fermenter volume ranges from about 1,000 to 600,000 gallons, with an 

average volume of 150,000 gallons.

Modern wine production occurs in steel fermenters fitted with a variety of process 

controls, i.e., temperature controls, including jackets through which refrigerant can be 

pumped, thermostats, and computerized controls that can maintain the temperature of 

the must within one or two degrees. Wine is a food product and fermenters are 

operated consistent with U.S. Food and Drug Administration (US FDA) food safety 

requirements. Sanitation procedures include sterilization of fermenters between each 

batch. In the case of red wine fermenters, equipment used to transport solids to the 

presses, and the presses themselves are sterilized consistent with US FDA 

requirements. Industry representatives have stated that sterilization of fermenters is 

mainly a manual process, using portable equipment that is moved from tank to tank.

As stated previously, large wineries in the SJV have annual wine production capacities 

of tens of millions of gallons. Fermenters at these facilities are typically designed to 

serve as both fermenters and storage tanks. Industry representatives have stated that 

 

14 All Fermenter and Storage Tank Statistic’s compiled from Permit Database Query, October 19, 2005
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 12 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

the selection of a given tank for a given fermentation batch may be dependent upon 

several operational parameters, i.e., type of wine being produce (white versus red), 

production of varietal wines, or appellations, availability of tanks in use, and planned 

capacity for storage.

Fermenters used to produce red wines have design features not found in fermenters 

exclusively used to produce white wines. When producing red wines, the juice is 

fermented in contact with the solids. Red wine fermenters are designed and equipped 

to manage the solids during fermentation and to transport the solids to presses where 

entrained wine is separated from the solids, after or during fermentation. Fermenters 

exclusively used to ferment white wines lack these features because solids are 

separated from the juice before the start of fermentation.

Storage Tank Usage

Of the 4,534 wine fermentation and storage tanks contained in the District’s permit 

database, 4,085 tanks are designated for use as storage tanks. The sum of reported 

fermentation tanks and storage tanks exceeds the total number of reported tanks by 

2,627 tanks. This is reflective of the practice of using select tanks for both fermentation 

and storage. The majority of storage tanks are made of coated mild-steel or stainless 

steel; about 3% are made of concrete. Storage tanks are essentially fermenters with 

the manway closed. Previously presented information on construction and processing 

controls of fermenters applies to storage tanks. After fermentation, wine is transferred 

about six times between storage tanks to perform various polishing operations such as 

“racking” (decantation for separation of sediment), filtration, and malolactic fermentation 

(breakdown of malic acid to lactic acid and carbon dioxide). Because heat has 

deleterious effects on wine quality winemakers carefully control tank temperatures to 

maintain the quality of the product and to facilitate certain process operations. Storage 

temperatures are often maintained near the freezing point of the wine. Temperature 

control is achieved through use of cooling jackets and/or heat exchangers (i.e., wine is 

re-circulated from the bottom of the tank through a heat exchanger, and back into the 

tank). An insulating foam layer blankets tank exteriors.

As wine is pumped into or out of a tank, the pressure in the vapor space increases or 

decreases, respectively. Atmospheric temperature changes cause an expansion or 

contraction of the vapors in this space, again resulting in pressure increases or 

decreases. Storage tanks are fitted with pressure-vacuum relief valves that serve to 

maintain tank vapor-space pressures within safe pressure and vacuum operating design 

limits of the tank.

Emissions From Bulk Wine Storage

As previously presented, District staff calculates an emission factor for wine storage in 

the central valley of 0.372 lb EtOH/1000 gal wine processed. The analysis 

demonstrates that emissions from wine storage tank are primarily influenced by the 
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 13 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

number of volume exchanges that occur. Emission reductions resulting from use of 

pressure-vacuum relief valves (PVR) and temperature control were evaluated by 

performing two runs with TANKS 4.0. Both analyses are based on a 100,000-gallon 

storage tank containing a water/ethanol mixture having a 0.2816 mol fraction of ethanol. 

Run-1 simulated an average ambient temperature of 75 degrees Fahrenheit, no 

temperature control, and no PVR. Run-2 run simulated temperature control and use of 

PVR. Breathing losses were calculated to be 68.29 lb/year for Run-1, and 65.19 lb/year 

for Run-2, for a delta of 3.1 pounds. Annual ethanol emission reductions attributed to 

use of a PVR on wine storage tanks was calculated as follows:

mol EtOH

46.02 lb EtOH

mol vapor

0.2816 mol EtOH

25.90lb

1mol vapor

 year

3.1lb - vapor

100,000gal

EtOH emissions

= x x x

Multiplying the resulting emissions factor of 0.016 lb EtOH/1000 gallons times a total 

annual production volume of 338,000,000 gallons results in an emission reduction 

attributable to use of PVR of 3 tons per year.

IV. ESTIMATED REDUCTIONS

Baseline Emissions

Baseline emissions were established using an annual wine fermentation of 37,968,011 

gallons 15. As previously presented, the percentage of red and white wine has a 

significant effect on baseline determination. For completeness, the baseline was 

calculated using ARB methodology, and Wine Institute percentages. As presented in 

Table-6, baseline annual VOC emissions from all wine fermentation are estimated to 

range from 673 to 788 tons.

Table-6 2002 Wine Fermentation Emission Baseline 

Wine Type Annual Production (%) VOC Emissions (tons/year)

Scenario-1

Red Wine 60% 613

White Wine 40% 145

Total 788

Scenario-2

Red Wine 40% 398

White Wine 60% 262

Total 660

 

15 U.S. Department of the Treasury, Alcohol and Tobacco Tax Bureau 2002 alcohol production statistics
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 14 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

Exemption of Small Wineries

Stationary sources operating in the District that have annual emissions of at least ten 

tons VOC or NOx are considered significant sources of air pollution. The Federal Clean 

Air Act (CAA) requires all major sources to have at least RACT level control on all 

devices that emit pollution at their facilities. Draft Rule 4694 would exempt small 

wineries (wineries with less than 10 tons annual fermentation emissions) from VOC 

vapor control requirements. As demonstrated below, exempting wineries with annual 

fermentation emissions of less than ten tons represents 5.5% of the annual baseline 

emissions (788 tons).

Emissions attributable to wineries with annual fermentation emissions of less than or 

equal to 10 tons were determined by calculating the annual fermentation volume 

required to equal 10 tons VOC, and then using Table-5 to determine the number of 

wineries below the production threshold. The annual production volume was calculated 

using the following formula:

Where,

• 10 Tons is the annual fermentation VOC emissions threshold

• 58.5%Total and 41.5%Total are the estimated percentage of red and white wine 

production for all wineries

• 6.2 lb and 2.5 lb are the emission factors for red and white wine

Solving the equation for “Total”, results in an annual production threshold of 4.3 million 

gallons. Substituting the Wine Institute’s percentages for red and white wine 

production, and performing a similar calculation, results in an annual production 

threshold of 5.0 million gallons. According to the ABC permits database, about 5.4% of 

the total production would be exempted by a 10-ton emissions threshold.

Total emissions affected by the 10-ton threshold were estimated using the following 

calculation:

Exemption Emissions = 5.4% x Total annual emissions

Assuming total annual emissions range from 660 to 788 tons, the small winery threshold 

would exempt 36 tons to 43 tons of VOC from emission control requirements.

( ) ( )

2000 lbs

1 ton

1000 gal

6.2 lbs 2.5 lbs 10 Tons ×× + ×

=

58.5% Total 41.5%Total
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 15 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

Adjusted Annual Emissions Baseline

An adjusted annual emissions baseline of 624 ton to 745 tons was calculated by 

subtracting VOC emissions from exempted small wineries from the annual emissions 

baseline. 

Example: Adjusted Baseline = 660 tons – 36 tons

Adjusted Baseline = 624 tons

Achievable Emission Reductions

Draft Rule 4694, Section 5.0 requires operators to achieve a 35% reduction in their 

annual VOC emissions from wine fermentation. Achievable emission reductions were 

estimated to range from 218 tons to 261 tons VOC. Achievable emission reductions 

were calculated by multiplying the Adjusted Annual Emissions Baseline by 35%.

Example: Achievable Emission Reductions = (624 tons) (35%)

Achievable Emission Reductions = 218 tons annually

Average daily emission reductions were estimated by dividing Achievable Emission 

Reductions by 365 days. Average daily emission reductions were estimated to range 

from 0.60 tons to 0.72 tons per day. Daily reductions in this range are expected to meet 

the District’s Extreme Ozone Plan commitment of 0.7 tons per day.

Example: Daily Reductions = 218 tons/365 days

Daily Reductions = 0.6 tons/day
SAN JOAQUIN VALLEY UNIFIED AIR POLLUTION CONTROL DISTRICT

Appendix B: Emissions Reduction Analysis for Rule 4694 December 15, 2005

B - 16 Final Staff Report with Appendices 

For Revised Proposed Rule 4694

This page intentionally blank