There are 54 grading factors for wheat included in the grain grading guide provided by the Canadian Grain Commission (CGC), but many may be surprised to learn that falling number isn’t one of them. It may not be a grading factor, but falling number is used as a world standard in the grain and flour milling industries for wheat, durum, triticale, rye, and barley, and a minimum may also be included as part of a grain contract.
Falling number determines if a sample of grain has experienced sprouting or pre-harvest germination caused by damp or rainy weather during the final maturation of the crop. When these conditions occur, the production of starch-degrading enzyme alpha-amylase is accelerated, which affects processes during bread baking. To summarize, low falling number equals really ugly bread, and for a bread wheat crop, that’s all bad.
A high falling number indicates the wheat is sound and satisfactory for most baking processes. For example, the CGC says a No. 1 CWRS normally has a falling number greater than 350 seconds.
It pays to know what you’ve got on hand, as falling number may be part of your grain contract, even though it isn’t a legal grading factor. In order to know the falling number, you’ll need a test. You’ll need a representative sample of grain, whether you bring it to an elevator ahead of delivery or send it in for a third-party assessment, such as to the CGC.
To ensure you’ve got a representative sample make sure to take samples throughout the field while combining, and thoroughly mix the sample. Always keep a subsample (or two) in case it needs to be retested or in case of discrepancy. Double-check your contract to make sure falling number is or isn’t a part of it so there’s no surprise downgrade based on the quality parameter.
If you do send in a sample to the CGC, you’ll receive an unofficial grade (since samples aren’t usually collected by a Canadian Grain Commission inspector). Still, as part of the Harvest Sample Program, you can receive a grade and the falling number data from what you send in. Data from samples is used to make crop quality data available to marketers to promote the sale of Canadian grain, and average falling number is one of the parameters end-users and customers ask for.
How is Falling Number Determined?
Falling number is determined by measuring the time it takes for a stirrer to fall through a slurry of ground wheat and water. The protocol below is set out by the Canadian Grain Commission, however, ask your local grain elevator what protocol is used and how it is verified/vetted for accuracy.
- A moisture test is done on a representative wheat sample that has been ground
- A seven gram subsample is measured, based on a 14 per cent moisture basis
- Distilled water is added to the ground sample in a falling number test tube
- The ground wheat and water mixture is throughly shaken to form a slurry
- A stirrer is placed in each falling number tube
- Tubes containing the slurry and a stirrer are immersed in a boiling water bath in the falling number apparatus and the slurry is stirred for 60 seconds, then the stirrer is allowed to drop by its own weight through the slurry
- The total time in seconds it takes the stirrer to reach the bottom, including the 60 second stirring time is the falling number result.