United States Grade Standards for Soybeans

As with the other U.S. grain standards, a lot is first classed and then graded. Classing for soybeans turns on colour — of the seed coat and of the hilum — because colour carries into processed products and because certain buyers, particularly in food-soy markets, contract specifically for it. The numerical grade then follows from factors measured on a representative sample, with the poorest factor determining the outcome and a sample grade applying to lots that fall outside the numbered grades or carry specified objectionable characteristics.

This page does not enumerate the numbered grades. The number of grades, their designations, and the limits attached to each are set in the official text; readers needing the scale itself should take it from USDA FGIS rather than from a summary.

The soybean factor set overlaps with the cereal standards but adds two factors that only make sense for this commodity:

• Test weight per bushel — a bulk-density measure used as a general soundness indicator
• Damaged kernels (total) — beans materially damaged by any cause
• Heat-damaged kernels — limited separately and more strictly than total damage
• Foreign material — material other than soybeans remaining after the prescribed separation
• Splits — beans separated into halves, with the seed coat broken or removed
• Soybeans of other colours — off-colour beans within a lot of a given class

Splits are the distinctive factor. A soybean is two cotyledons held together, and dry or roughly handled beans separate cleanly along that natural line — so splits are largely a record of moisture condition and handling, not of any problem in the field. They matter to processors because a split bean has lost its seed coat and exposes oil-bearing tissue, which affects storage stability and processing behaviour.

Soybeans of other colours is a class-purity factor rather than a soundness factor. It exists because colour has commercial consequences downstream, and it is a good illustration of a general point about grading: not every grading factor describes damage. Some simply describe whether the lot is what it says it is.

The grade describes soundness, cleanliness, and class purity. It does not describe the two things much of the market actually buys soybeans for — oil content and protein content — which are determined and traded separately, and which are why crush margins and food-soy premiums are negotiated outside the grade entirely. Nor is a grade a food-safety determination.

A grade attaches to the lot the sample represents. Official grading depends on prescribed sampling and handling procedures: sampling method, sample size, and lot definition follow official procedure rather than party agreement, because an unrepresentative sample produces a grade that describes nothing real.