Today in 1982, US Patent 4315038 A was issued, an invention of Phillip M. Townsley and Robert L. Weaver, assigned to The Molson Companies Limited, for their “Process for Preparing Protein Flour from Brewery Waste .” Here’s the Abstract:

Trub obtained from the wort kettle of a brewing system is rich in protein and thus can be used in human foods. The trub is processed to yield a trub flour by extraction with an azeotropic mixture of isopropanol and water, and drying to remove the solvent in a roller drum drier, the latter yielding the trub flour in dry flake form.