How can you recognize frost-damaged soybeans? Watch for these characteristics:

  • Green or elongated yellow soybeans that shrink to smaller than normal size after drying
  • Reduced oil content and quality
  • Higher moisture level (by 1-2%) than indicated by a moisture meter
  • Slower field drydown

Soybeans left standing in the field may lose green color within two weeks of maturity, so allow for field dry-down if possible, even if the plants were only partially frosted.

Does the color of green soybeans change during storage? In a preliminary study done at the University of Minnesota by Extension Agricultural Engineer Bill Wilcke and others, green soybeans and normal yellow beans were stored and monthly color readings were taken for six months. The colors did not change significantly for either group; however, visual appearance of the pure green soybeans appeared to be slightly mottled at the end of the six-month period. Some growers believe that beans that are only slightly green will tend to lighten up with time.

A study conducted at the University of Minnesota indicated that if green beans were properly dried to low, safe storage moistures, they should keep in storage.

It may be desirable to try to screen out small green soybeans as a means to reduce potentially large discounts due to damage. If you are storing soybeans that require drying, be sure to dry them (at temperatures of less than 130° F) to a low moisture level in order to ensure safe storage. In the Midwest, the Midwest Plan Service generally recommends storage moistures of 12% or lower for clean, high-quality soybeans in aerated storage for up to one year. For damaged soybeans, the storage moisture content should be 11% or lower.