Today in 1980, US Patent 4197321 A was issued, an invention of Gustav W. Chyba and John H. Dokos, assigned to Anheuser-Busch, Incorporated, for their “Process for Brewing Beer and Treating Spent Grains.” Here’s the Abstract:

In the brewing of beer, spent grain at about 90% moisture from a straining tank having no internal rotating rake is collected and pumped to a centrifuge which reduces the moisture of the spent grain to about 70% and provides spent grain liquor of about 2.0 to 4.5% or more of total solids. The spent grain liquor is stored in a tank at 165° F. to 170° F. and held until it is used up to 50% of the sparge liquid for a subsequent brew in the straining tank. The spent grains at about 70% moisture are directed to a large holding tank. Nutritious brewery waste streams are added thereby increasing the nutritional value.