For wheat farmers, particularly those cultivating soft white wheat, encountering falling numbers and receiving discounts at the elevator can be a common challenge. Falling numbers tests play a crucial role in assessing the quality of wheat, but what exactly do they measure and why are they significant?
What Happens to Wheat After Maturity?
At physiological maturity, a wheat seed is composed of 83% endosperm (used for white flour), 14.5% bran (for whole wheat flour), and 2.5% germ. However, excessive rainfall during wheat harvest can lead to preharvest sprouting, where seeds absorb water and start the germination process. This triggers the production of alpha-amylase, an enzyme that breaks down starch into simpler carbohydrates like sugar. This process alters the wheat's composition and can affect vital components like gluten.
What is a Falling Number Test?
A falling number test gauges the extent of preharvest sprouting in wheat grains while still in the field. Conducted at elevators, the test involves grinding a sample into flour and creating a slurry with water. A plunger is inserted, and the time it takes for the plunger to descend to the bottom of the test tube is measured. Typically ranging from 300 to 400, a higher falling number indicates delayed descent, reflecting minimal enzymatic activity and limited starch breakdown. Conversely, a low falling number indicates increased enzymatic activity and starch degradation.
Why Does Falling Numbers Matter?
Wheat flour, essential for baking, relies on balanced starch content. If starches have converted into simpler carbohydrates due to preharvest sprouting, baking processes can be disrupted, affecting fermentation, rise, and overall quality. Mills can blend wheat with varying falling numbers to achieve desired balances, but farmers struggle with this due to the significant amount required to counter low falling numbers’ effects.
What Causes Low Falling Numbers?
Low falling numbers have two main triggers: preharvest sprout and the presence of late maturity alpha-amylase. The former arises from cool, rainy weather after wheat's golden stage, visibly damaging the crop. The latter is caused by temperature fluctuations during grain maturation. Genetics also play a role, with some wheat varieties being more susceptible. Soft red winter wheat, for instance, exhibits fewer falling number issues compared to soft white winter wheat.
Understanding Variability in Falling Numbers Variability in falling numbers can be attributed to factors such as microclimates within fields, sample size limitations, and procedural inconsistencies during testing. The weather's role is significant, creating diverse environments within fields that impact preharvest sprouting. Ensuring representative samples and consistent testing procedures remain challenges due to the small sample sizes involved.
In essence, falling numbers tests serve as important indicators of wheat quality, particularly in baking. Understanding the causes of low falling numbers and the variables that influence them can empower wheat farmers to make informed decisions to enhance their crop's market value.
Photo Credit: istock-zhaojiankang
Categories: Michigan, Crops, Wheat