United States Department of Agriculture

Agricultural Marketing Service

Federal Grain Inspection Service

Directive 9180.38 May 1, 2019

The U.S. Department of Agriculture (USDA) prohibits discrimination in its programs 

on the basis of race, color, national origin, sex, religion, age, disability, political 

beliefs, and marital or familial status. (Not all prohibited bases apply to all programs.) 

Persons with disabilities who require alternate means for communication of program 

information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET 

Center at (202) 720-2600 (voice and TDD).

To file a complaint, write to the USDA, Office of Civil Rights, Room 326-W, 1400 

Independence Avenue, SW, Washington, DC 20250-9410, or call (202) 720-5964 

(voice and TDD). USDA is an equal employment opportunity employer.

Distribution: FGIS, OSP, Industry Originating Office: TSD, ACB

DETERMINATION OF FALLING NUMBER FOR WHEAT

Contents

1. PURPOSE............................................................................................................. 2

2. REPLACEMENT HIGHLIGHTS............................................................................. 2

3. BACKGROUND..................................................................................................... 4

4. DEFINITIONS........................................................................................................ 4

5. EQUIPMENT AND SUPPLIES.............................................................................. 5

6. EQUIPMENT QUALITY CONTROL PROCEDURES............................................ 7

7. BASIS OF DETERMINATION ............................................................................... 8

8. SAMPLING............................................................................................................ 9

9. PREPARATION OF GROUND WHEAT................................................................ 9

10. FALLING NUMBER DETERMINATION .............................................................. 10

11. AVERAGING SUBLOTS ..................................................................................... 14

12. COMPOSITE SAMPLE ANALYSIS..................................................................... 15

13. CERTIFICATION................................................................................................. 16

14. RETEST AND APPEAL....................................................................................... 17

15. QUALITY CONTROL........................................................................................... 17

16. TROUBLESHOOTING ........................................................................................ 18

17. REFERENCES.................................................................................................... 18

18. INQUIRIES.......................................................................................................... 18

19. ATTACHMENTS ................................................................................................. 18
FGIS Directive 9180.38 May 1, 2019

Page 2

1. PURPOSE

This directive provides procedures for determining falling number (FN) and 

certifying the results for wheat only. The service is provided upon request under 

the authority of the Agricultural Marketing Act of 1946, as amended (AMA). 

Testing services are available at selected Agricultural Marketing Service (AMS), 

Federal Grain Inspection Service (FGIS) field offices, official agencies, and the 

Technology and Science Division (TSD).

This directive also provides, upon request of the applicant, FN test results on a 

United States Grain Standards Act (USGSA) inspection certificate. This 

certification procedure is applicable only to FN tests that are performed in 

conjunction with other testing services performed under USGSA. FN testing 

performed independent of USGSA services must be reported on an AMA 

inspection certificate.

2. REPLACEMENT HIGHLIGHTS

This directive supersedes FGIS Program Directive 9180.38, Falling Number for 

Wheat, dated May 20, 2013. The following, significant changes were made:

• Adobe Acrobat is required to open the attachments in this 

document.

• Updated the format to be consistent with FGIS Administrative 

Directive 3010.2;

• Added a section for definitions;

• Revised the list of equipment and supplies to be more specific and 

reflect equipment currently supported by Perten Instruments;

• Added section for equipment quality control procedures;

• Required the use of specific digital barometer and thermometer

models;

• Required barometer accuracy to be verified by TSD and the 

thermometers to have a National Institute of Standards and 

Technology (NIST) traceable calibration;

• Removed the requirement to calibrate the barometer using the 

nearest weather station information;
FGIS Directive 9180.38 May 1, 2019

Page 3

• Eliminated the use of mercury thermometers;

• Changed the tolerance for measured water temperature to account 

for measurement uncertainty;

• Required collecting ground wheat in a plastic bag, closing, and 

shaking to mix prior to taking a test portion;

• Eliminated requirement to run grinder for at least one minute after 

each sample and inserted requirement to clean the grinder 

chamber and cyclone after each sample;

• Required addition of the homogenized ground wheat to the 

viscometer tube prior to addition of water;

• Clarified the FN tube scraping procedure and added the 

explanation that failure to scrape causes a lower FN;

• Incorporated FGIS Policy Bulletin #264 – “Certification of Falling 

Number Based on Composite Samples”;

• Increased the time of sample preparation before placing the FN 

tube in the water bath from 40 to 60 seconds, bringing the time into 

agreement with that stated in the American Association of Cereal 

Chemists (AACC) International method 56-81.03, “Determination of 

Falling Number”;

• Incorporated three Microsoft Excel 2016 worksheets as 

attachments to perform all calculations previously requiring lookup 

tables;

• Removed the lookup tables associated with altitude-corrected FN 

values, converting between FN and liquefaction numbers, 

predicting percent moisture in ground wheat samples, and the 

boiling point of distilled water referenced to barometric pressure.

• Required the use of the Shakematic for shaking samples and 

eliminated the option of shaking samples by hand;

• Implemented a new procedure for adjustment of FN based on 

barometric pressure instead of altitude;
FGIS Directive 9180.38 May 1, 2019

Page 4

• Changed contact for inquiries to the Falling Number Program, 

Analytical Chemistry Branch;

• Inserted the option to use deionized water;

• Required the use of a bottle-top dispenser in place of a graduated 

cylinder or automatic pipette;

• The troubleshooting section was included as attachment 4.

3. BACKGROUND

The FN method is an indirect measurement of the amount of alpha-amylase 

activity in wheat. High alpha-amylase activity is associated with the natural 

germination process that results in the breakdown of starch and ultimately in 

sprouting of the wheat kernel. High alpha-amylase activity adversely affects the 

end-use quality of wheat, and as a result, assessment of this factor is important 

in the domestic and international trade of wheat. 

The FN result is the time in seconds required for the instrument to mix the 

sample with a viscometer-stirrer, release the viscometer-stirrer, and allow it to fall 

through the hot aqueous mixture. A high FN indicates a high viscosity of the 

mixture and low alpha-amylase activity. A low FN indicates a low viscosity of the 

mixture and high alpha-amylase activity. 

4. DEFINITIONS

a. Wheat – whole-kernel, wheat grain as defined in book II, chapter 13 of the 

FGIS Grain Inspection Handbook.

b. Gram (g) – a metric system unit of measurement for mass.

c. Milliliter (mL) – a metric system unit of measurement for volume.

d. Barometric Pressure (P ) – atmospheric pressure as measured by a 

barometer. For the analytical method herein, the barometric pressure is 

the absolute pressure reported in inches of mercury (inHg).
FGIS Directive 9180.38 May 1, 2019

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5. EQUIPMENT AND SUPPLIES

This section specifies the equipment and supplies needed to perform the FN test. 

In certain cases, other supplies may be substituted with written approval from 

TSD.

a. Equipment and Supplies from Perten Instruments North America 

(Springfield, IL).

(1) Falling Number Instrument. Model No. FN 1000, FN 1500, FN 

1700, or FN 1900 (FN 1400, FN 1600, and FN 1800 models are no 

longer supported by Perten Instruments and replacement with a 

supported model is recommended).

(2) Cooling Tower 1000. Fits all FN Models. Part No. 011050.

(3) Plastic tubing for cooling system. Part No. 30718.

(4) Spiral hose collector. Part No. 31037.

(5) Flow indicator. Part No. 106571.

(6) Hose clamps for cooling tubing. Part No. 30099.

(7) Bottle. For refilling water bath. Part No. 30690.

(8) Hose Kit for Water Bath Refill System. Part No. 31105.

(9) Viscometer Tubes. Certified for falling number test, Part No. 

10.03.00. 

(10) Viscometer Tube Rack. Part No. 100800.

(11) Plastic Funnel. Part No. 100600.

(12) Cassette Stand. Part No. 160810.

(13) Stand for Holding Cassettes and Tubes. Part No. 160440.

(14) Viscometer-stirrer. Part No. 160400.

(15) Shakematic 1095. Part No. 011090.

(16) Shakematic Tube Stopper. Part No. 109070.
FGIS Directive 9180.38 May 1, 2019

Page 6

(17) Mains Power Cable for Shakematic. Part No. 100119 (115 V).

(18) Spolett Tube Cleaner. Part No. 191100.

(19) Grinder. Laboratory Mill Model 3100, with 0.8 mm sieve. Part No. 

031011 (115V, 60 Hz). 

(20) Cyclone. Used with grinder for sample collection. Part No. 310500.

(21) Plastic Baton. Used to clean grinding chamber of LM 3100. Part 

No. 310430.

(22) Grinding Chamber Brush. Used to clean grinding chamber of 

LM3100. Part No. 311440.

(23) Cylcone Brush. Used to clean cyclone attachment. Part No. 

310260.

b. Other Equipment and Supplies

(1) FGIS-approved divider. 

(2) GAC2500-UGMA or Perten AM520 moisture meter. For additional 

information refer to the FGIS Moisture Handbook.

(3) Digital Barometer. Accuracy ± 0.12 inHg and Precision ± 0.03 inHg

or better. Testo 511, Part No. 0560 5011 (Testo, Inc., Sparta, NJ) 

or Fisher Scientific Barometer, Part No. 14-650-118 (Fisher 

Scientific, Hampton, NH). 

(4) Digital Thermometer with NIST-Traceable Calibration. Accuracy ± 

0.4°C and Precision ± 0.1°C, Part No. 06-664-27 (Fisher Scientific). 

(5) Balance. A precision-class balance accurate to within ± 0.02 g. 

(6) Distilled or Deionized Water. Used for water bath and addition to

sample test portion. 

(7) Water Dispenser. Bottle-top dispenser, 2.5–25 mL, with discharge 

tube, telescoping filling tube, spare dispensing cartridge, 45/33mm 

and 45/38 mm thread polypropylene adapter, and operating 

manual, Accuracy ± 1.2% and Precision ± 0.2%, Part No. 13-688-

247 (BrandTech, Essex, CT).
FGIS Directive 9180.38 May 1, 2019

Page 7

(8) 2L Bottle. For use with the bottle-top water dispenser with 45/33 

mm or 45/38 mm threads (bottles of other volumes may be used). 

Use of an amber-colored bottle is preferred for inhibiting microbial 

growth.

(9) Weighing boats or metal weighing pan.

(10) Plastic bag. Any sealable plastic bag large enough to contain the 

ground sample being no more than 2/3 full and thick enough to 

resist tearing.

(11) Test tube brush. Used to clean viscometer tubes.

6. EQUIPMENT QUALITY CONTROL PROCEDURES

a. Falling Number Instrument.

CAUTION: Use only distilled or deionized water in the water bath. 

CAUTION: Do not add chemicals to adjust the water bath 

temperature as this will result in erroneous results.

(1) Water Level. Periodically check the water bath level while running 

FN tests. Some instrument models have an overflow tube on the 

water bath. The water level should be at the overflow level when 

viscometer tubes are in place. Immediately after a FN test in which 

the water level was at the overflow outlet, mark the new water level 

on the water level indicator. Maintain the water height at the mark, 

so that when a set of FN tubes is inserted, the water will rise to the 

overflow outlet. 

(2) Water Bath Temperature Check. Before the initial test of each day 

and after adding distilled water to the bath, verify that the bath 

temperature is correct for the barometric pressure in the lab. 

(a) Measure the barometric pressure using the barometer and 

measure the temperature of the water bath by inserting the 

thermometer in the center of an opening to the bath to a 

depth of 3.5 inches. The probe may be lightly etched for 

referencing the distance.

(b) Enter the barometric pressure (P) and temperature 

measurements into the attachment 1. This worksheet is set 
FGIS Directive 9180.38 May 1, 2019

Page 8

to calculate the difference of the measured temperature from 

the predicted temperature using equation 1. 

Equation 1. Water Bath Check

Difference (%) = Measured Temp. - (0.9586 × P + 71.696)

(c) If the measured temperature differs from the predicted

temperature by more than ± 0.5°C, correct the problem

before proceeding. Refer to the attachment 4 for

troubleshooting tips to help in resolving the problem.

b. Viscometer Tubes. Replace when worn and scratched.

c. Grinder. Replace the sieve (Part No. 310230) at least every 1,000

samples or sooner whenever it appears damaged.

d. Digital Barometer. The barometer must be set to read absolute pressure

using inHg. New barometers must be sent to TSD for verification of

accuracy and every 2 years thereafter.

e. Digital Thermometer. The accuracy of the thermometer must be verified to

be within the specification at least once every 2 years. The thermometer

may be purchased with a NIST-traceable calibration, and calibration

services are commercially available.

f. Balance. Verify accuracy of balance daily using a 5-g reference weight.

The mass must be 4.98–5.02 g to be considered acceptable.

g. Bottle-top Dispenser. Operate according to the manufacturer’s manual.

Check the accuracy of the water dispenser at the beginning of each day

falling number testing is performed. Set the water dispenser to 25.0 mL

and dispense the nominal amount of water into a tared container. The

mass should be in the range of 25.0 ± 0.3 g based on the density of water

being 0.998 g/mL at room temperature (20–23°C). If the mass is not in this

range, calibrate the water dispenser per the manufacturer’s instructions.

7. BASIS OF DETERMINATION

The FN test is based on a 7 g representative portion taken from 250 g of ground

wheat. Sufficient wheat must be ground to yield 250 grams of flour. Remove

dockage and stones from the sample before grinding. See section 10.b. for more

details.
FGIS Directive 9180.38 May 1, 2019

Page 9

NOTE: All FN determinations are performed in duplicate and reported, on 

the official certificate, as the average of the two measurements. 

FN results are reported on a 14 percent moisture basis unless the applicant 

specifies another moisture basis. The applicant may request to have the FN 

results reported on the "as is" moisture basis, dry matter (zero percent moisture) 

basis, or any other specified moisture basis. Only one moisture basis is reported 

on any one certificate.

There are three certification options available for export lots:

(1) Individual sublot samples.

(2) Average of sublots using the approved method (see section 12 for

more details).

(3) Composite sample representing the entire lot (see section 13 for

more details).

NOTE: Applicants must specify the certification option to use prior to 

loading.

8. SAMPLING

Refer to the FGIS Sampling Handbook for official sampling procedures. Use an

FGIS-approved divider for obtaining the amount required for the FN test.

9. PREPARATION OF GROUND WHEAT

a. Moisture Determination.

(1) Determine the moisture content of the wheat using a GAC2500-

UGMA or Perten AM 5200-A moisture meter. Refer to the Moisture

Handbook for more details.

(2) If the moisture is above 15.9 percent, air dry the sample, using an

open pan at room temperature, to a moisture content of 15.9

percent or less before grinding.

(a) Air drying to 15.9 percent moisture is not required for “as is”

certification.
FGIS Directive 9180.38 May 1, 2019

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(b) Air dry enough so that the weight after drying is at least

250 g.

b. Grinding and Homogenization.

(1) Remove dockage and stones from the wheat before grinding.

(2) Grind a minimum of 250 g of wheat using a Perten Lab Mill 3100.

(3) Collect the sample in a plastic bag. Do not reuse the plastic bag.

(4) Close the bag and shake the sample for at least 10 seconds to

homogenize the ground wheat prior to taking a test portion.

(5) Clean the grinding chamber and cyclone between samples using a

brush and vacuum.

10. FALLING NUMBER DETERMINATION

CAUTION: Steps a, b, and c, must be completed and the FN instrumental

analysis (step d) started within 60 seconds after adding the water. Perform

all FN determinations in duplicate as follows:

a. Weighing Test Portions and Addition of Water.

(1) Weigh 7.00 ± 0.05 g of the homogenized ground wheat into a

clean, dry weighing boat or metal weighing pan and then transfer

the entire test portion to the viscometer tube using a plastic funnel.

Then lightly tap the funnel a few times to get all dry matter into the

tube. Repeat for the second test portion.

(2) Tilt the viscometer tube and tap or rotate the tube so that a portion

of the tube bottom is not covered by the wheat. This will allow the

water to reach the bottom of the tube and help prevent clumping.

(3) While the tube is tilted, dispense 25.0 ± 0.3 mL distilled or

deionized water and straighten the tube as it fills.

(4) Complete steps 2 through 3 for the second viscometer tube and

immediately proceed to step b, Shaking the Viscometer Tube.
FGIS Directive 9180.38 May 1, 2019

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b. Shaking the Viscometer Tube.

(1) Open the doors on the Shakematic by pressing the [OPEN] button.

The [START] button will blink green.

(2) Insert a Shakematic tube stopper into the viscometer tube.

(3) Insert the bottom of the tube into the hollow of the holder, and then

push the upper part of the tube into the top of the holder.

(4) Close the doors manually. The [START] button will become a

steady green light.

(5) Press the [START] button. The shaking starts and the green

[START] button will turn red. The Shakematic will stop after a few

seconds, and the doors will automatically open when the shaking is

complete.

(6) Carefully remove the viscometer tubes by first pulling the upper part

out of its holder. Ensure no clumps or dry matter are visible in the

tubes. If clumps or dry matter are present, start the process over

with a new sample.

(7) Immediately proceed to step c, Scraping the Stopper and

Viscometer Tube.

c. Scraping the Stopper and Viscometer Tube.

CAUTION: Failure to scrape the slurry residue from the stopper into

the tube and from the tube walls down into the slurry will decrease

the FN test result.

(1) Remove the stopper from the viscometer tube.

(2) Scrape the slurry coating fully from the stopper into the tube.

(3) Scrape the slurry coating the wall of the tube down to the top of the

slurry with the viscometer-stirrer. Make sure scraping is thorough to

ensure the slurry is scraped cleanly off the sides of the tube.

(4) Repeat step 1 through 3 for the second viscometer tube.

(5) Immediately proceed to step d, FN Instrument Analysis.
FGIS Directive 9180.38 May 1, 2019

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d. FN Instrumental Analysis.

(1) Place the tube and the viscometer-stirrer into the FN instrument’s

water bath tube holder and start the instrument.

(2) Once the instrument is finished, record the FN readings from the

instrument.

There is very little alpha-amylase activity in samples with a FN

result above 400 seconds at sea level (29.92 inHg). Thus, when the

FN results exceed 400 seconds at sea level, record the result on

the certificate as “more than 400 seconds.” Each official service

provider will need to determine FN reading that is equivalent to 400

seconds at sea level entering the measured barometric pressure at

their location into attachment 2. If the applicant requested the

actual FN results or the actual result is needed for sublot analysis,

allow the test to continue until completion.

di. Cleaning the Viscometer Tubes.

CAUTION: Do not use soap or detergent to clean the viscometer

tubes. Clean the tubes only per the manufacturer’s recommendation.

Clean the viscometer thoroughly between samples.

(1) Hold the viscometer tube under running water and remove the

viscometer-stirrer.

(2) Using a Spolett or brush, clean the viscometer-stirrer and

viscometer tube thoroughly, making certain that all gelled material

is removed from inside the black, ebonite neck of the viscometerstirrer.

dii. FN Data Entry, Measurement Agreement, and Correction.

Attachment 2 has a table for data entry. Each row is for recording test

information for a sample. Enter the date of inspection, instrument serial

number, sample ID, measured moisture, specified moisture basis, and the

two FN measurements. The file can be saved locally for use.

The table is set up to calculate the average FN result, agreement of the

duplicate measurements, and pressure corrected FN under “as-is” 
FGIS Directive 9180.38 May 1, 2019

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moisture basis and specified moisture basis according to the following 

procedures.

(1) Average FN. The average FN is calculated according to equation 2.

Equation 2. Average Falling Number

FFFFAA = (FFFF1 + FFFF2) ÷ 2

where FNA is the average FN, and FN1 and FN2 are the two results 

from duplicate analysis of the sample

(2) Agreement of Duplicate Measurements. For samples having a

reading 400 seconds or less, the maximum allowable difference of

the two results from the average is 5.00 percent. This requirement

does not apply to samples for which both readings are greater than

400 seconds.

(a) If the first set of duplicate results are within ± 5.00 percent

from the average of the two tests, certify the results. If the

duplicate results differ by more than ± 5.00 percent from the

average of the two tests, proceed to the next step.

(b) Repeat the test with the same ground sample. If the results

are within tolerance, certify the results. If not, proceed to the

next step.

NOTE: If the results from the second set are not within

the tolerance, inform TSD.

(c) Grind a new portion of the sample and perform the falling

number test again. If the results are within tolerance, certify

the results. If not, proceed to the next step.

(d) Repeat the falling number test. If the results are within

tolerance, certify the results. If not, consult the

troubleshooting section and fix any instrument issues. If

instrument issues cannot be resolved, use another

instrument (if available) or contact Perten Instruments.

(e) After resolving the issue, repeat testing with original ground

sample and check the measurement agreement again.
FGIS Directive 9180.38 May 1, 2019

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(3) FN Pressure Correction. The average FN is corrected to sea level

using the barometric pressure according to equation 3. The

equation is applicable to elevations from 0–5000 ft.

Equation 3. Pressure Corrected Falling Number 

FNPC = 60 + 10[log(FNA – 60) + (-0.0214 x (29.9213 – P))]

where FNPC is the pressure corrected FN, FNA is the average FN, 

and P is the barometric pressure measured in inHg. 

NOTE: The pressure corrected FN derived above is the FN for 

the “as-is” moisture basis. No moisture correction is applied.

(4) Moisture Correction. The pressure corrected FN is adjusted for the

moisture basis of 14.0 percent as the default. Another value for the

moisture basis may be used, if specified by the applicant.

The FN for a particular moisture basis (FNMB) other than “as-is” is

determined according to equation 4.

Equation 4. Falling Number Moisture Correction 

FNMB = FNPC x (100 – MB) ÷ (100 – (1.904606 + (0.81661 x M)))

where FNMB is the FN at a specified moisture basis, FNPC is the

pressure corrected FN,MB is the moisture basis, andM is the 

percent moisture determined by the GAC2500-UGMA or Perten AM 

5200-A moisture meter. 

11. AVERAGING SUBLOTS

Enter the pressure corrected FN for each sublot into attachment 3. A special

formula is used to average the sublot results, because FN values do not have

additive properties. Low FN results have a pronounced affect in lowering the

average FN result when combined with a sample having a high FN reading. The

average sublot FN is calculated as follows:

a. Each sublot FN is converted to its Liquefaction Number (LN) equivalent

using equation 5.
FGIS Directive 9180.38 May 1, 2019

Page 15

b. The total (i.e., sum) and average of the sublot LN values are calculated.

c. The average sublot LN value is converted to its FN equivalent using

equation 6 and displayed to nearest whole number.

Equation 6. Conversion of Average Sublot Liquefaction Number to 

Average Sublot Falling Number

FFFFSS = (6,000 ÷ LL SS ) + 50

where FNSA is the sublot average FN and. LNSA is the sublot average LN.

12. COMPOSITE SAMPLE ANALYSIS

Criteria for composite sample analysis of export and domestic shipments not

graded under the CuSum plan are as follows.

If a lot of up to 5 railcars, 15 trucks, or 20 containers is receiving a single

certificate, the same group of carriers may also have FN determined from a

composite sample, or from a combination of the individual carrier results, and

reported on the same certificate. Carriers may not be grouped differently for FN

than for other factors. Please note that FN must not be averaged arithmetically.

Each FN must be converted to its LN, the average LN calculated, and the

average LN converted back to a FN using equations 5 and 6 in section 12.

Attachment 3 can be used for performing the calculations.

When carriers are receiving individual certificates, separate certificates may be

issued for falling numbers for groups of up to 5 railcars, 15 trucks, or 20

containers, and composite samples may be used for the FN test. These separate

certificates may be USGSA certificates, which also report official criteria such as

aflatoxin or protein, or they may be AMA certificates that report only FN.

An entire train can receive a FN from a single composite sample, regardless of

whether or not the lot was graded under the CuSum plan.

Equation 5. Conversion of Falling Number to Liquefaction Number

LLFF = 6,000 ÷ (FFFFPPPP − 50)

where FNPC is the pressure corrected FN.
FGIS Directive 9180.38 May 1, 2019

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13. CERTIFICATION

a. AMA Certification.

Report FN results on the inspection certificate (lot or sample) in

accordance with chapter 6 of the Processed Commodities Handbook.

On the inspection certificate, describe the commodity as "Wheat." Under

"Results of Inspection," report the FN result with the applicable statement

below. FN results are reported for certification to the nearest whole

number.

(1) "Falling Number:_____, percent moisture basis."

Use this statement to report FN results on any specified moisture

basis.

(2) "Falling Number:_____, dry matter basis."

(3) "Falling Number:_____, as is moisture basis."

Divided lot inspection certificates are available (for lot inspections only) 

upon request of the applicant.

b. Optional (USGSA) Certification.

(1) At the request of the applicant, FGIS will provide FN results in the

“Results” section of the USGSA inspection certificate.

(2) When FN results are reported on a USGSA inspection certificate

the following qualifying statement must be entered in the “Remarks”

section of the certificate.

“Falling Number results provided under the authority of the

Agricultural Marketing Act (AMA) of 1946.”

NOTE: This certification procedure is applicable only to FN tests that 

are performed in conjunction with other testing services performed 

under the USGSA. FN testing performed independent of USGSA 

services must be reported only on an AMA inspection certificate. 
FGIS Directive 9180.38 May 1, 2019

Page 17

14. RETEST AND APPEAL

A retest and/or appeal inspection is available upon request by the applicant. A

retest is performed on the basis of the whole grain file sample, and an appeal is

performed on the basis of the whole grain file sample or a new sample (AMA Part 

868.33 and 868.35).

a. A retest inspection may be performed by the same office that performed

the original inspection.

b. An appeal inspection, when requested by the applicant, may be performed

by an FGIS field office, TSD, or Federal/State office that monitored the

office that performed the original inspection or retest.

Official personnel shall not perform a retest or appeal inspection of a sample of 

which they participated in a previous inspection, unless there is only one 

authorized person available at the time and place of the requested service. Also, 

whenever possible, the retest or appeal inspection should be performed on a 

different FN apparatus than the one used for the original inspection.

The applicant may also request a retest and appeal inspection of individual 

sublots without separate certification. That is, a single inspection certificate for a 

shiplot may use original, retest, and appeal results for different sublots for the 

final certification.

The retest or appeal inspection shall be performed according to the procedures 

specified in this directive for original FN determinations.

15. QUALITY CONTROL

a. Quality control has been included in this directive by establishing

procedures for checking barometers, thermometers, balances, water

dispensers, and water bath temperatures to ensure proper operation of

equipment.

b. Monitoring and proficiency testing will be performed according to FGIS

Program Directive 9180.84, National Falling Number Quality Assurance

Program.

c. New FN instruments and repaired instruments must undergo a validation

according to FGIS Program Directive 9180.84 before use in delivering

official certification of FN.
FGIS Directive 9180.38 May 1, 2019

Page 18

16. TROUBLESHOOTING

For troubleshooting tips, refer to attachment 4.

17. REFERENCES

• American Association of Cereal Chemists (AACC) International Method

56-81.03.

• Delwiche, S.R.; Rausch, S.R.; Vinyard, B.T. Correction of Wheat Meal

Falling Number to a Common Barometric Pressure at Simulated

Laboratory Elevations of 0 to 1500 Meters. Cereal Chemistry 2018, 00, 1–

8.

18. INQUIRIES

Direct any technical inquiries regarding this directive to the Falling Number

Program, Analytical Chemistry Branch by phone at (816) 891-0401 or

FGISFallingNumber@usda.gov. Direct any policy questions regarding this

directive to Gregory J. Giese, Policies, Procedures, and Market Analysis Branch,

at Gregory.J.Giese@usda.gov.

19. ATTACHMENTS

Some browsers may not show a navigation pane needed to open attachments. If the 

browser being used does not display a navigation pane on the left side of the

browser, a small triangle at center of the extreme left edge of the page, or the Adobe 

symbol at the bottom of the page, the document should be saved locally (on a 

computer or thumb drive) as a pdf. After saving locally, open the pdf and look for the 

navigation pane (usually on the left of the display). Attachments are accessed

through an icon resembling a paperclip. Click on the paperclip to see the

attachment(s). Double click on the attachment of interest.

Attachment 1: Water Bath Check

Attachment 2: Falling Number Data Entry, Validation, and Correction

Attachment 3: Average Sublot or Carrier Falling Number

Attachment 4: Troubleshooting Guide