Brewers' spent grain is a rich source of nutrients. A host of start-ups are now using it to make everything from vegan barley milk and leather to baked goods, crisps and even coffee; it even has potential to be used in areas like construction, cosmetics and paper.
https://www.bbc.com/future/article/20250206-how-brewers-spent-grain-is-being-turned-into-vegan-barley-milk-leather-and-cakes