Cereal Chem 39:487 - 493.  |  VIEW ARTICLE

Using a Density Gradient Column to Determine Wheat Density.

W. R. Peters and R. Katz. Copyright 1962 by the American Association of Cereal Chemists, Inc. 

A wheat kernel placed in a density gradient column will sink until it reaches the level where its average density is equal to that of the liquid at that level. Knowing the density of the liquid as a function of height, one can measure accurately the density of the kernel to three decimal places in about 1 to 2 minutes per kernel. Kernel density ranged from a maximum of 1.416 at 7.5% moisture to a minimum of 1.255 g./cm.[3] at 18.5% moisture, for the samples tested. Kernels of a homogeneously selected sample of hard spring wheat (Lee) varied in density from 1.29 to 1.41 g./cm.[3] at 12% moisture. A clear separation of grain infested with rice weevil from noninfested grain was found for larvae 20 days old by using a solution of density 1.26 g./cm.[3]. Protein and ash content have been found to vary with density, and to pass through a maximum in some cases.