Brewer's spent grain

Brewer's spent grain (BSG) or draff is a food waste that is a byproduct of the brewing industry that makes up 85 percent of brewing waste. BSG is obtained as a mostly solid residue after wort production in the brewing process. The product is initially wet, with a short shelf-life, but can be dried and processed in various ways to preserve it.

Because spent grain is widely available wherever beer is consumed and is frequently available at a low cost, many potential uses for this waste have been suggested and studied as a means of reducing its environmental impact, such as use as a food additive, animal feed, fertilizer or paper.