These are the remaining materials following fermentation of grains by yeast to digest starch and generate alcohol during the brewing or distilling process. Grains are commonly barley and corn but may include any grain or seed used as a source of starch for commercial alcohol production. Whilst the palatability tends to be quite high due to yeast content and remaining sugars, and the protein level also attractive from a nutrition standpoint, Brewers Grains are potentially dangerous and unsuitable for use as horse feed. The reason is that the product is at high risk of contamination by Mycotoxins such as Aflatoxin and others. Warmth and moisture present during production and subsequent storage are ideal conditions for mycotoxin producing mould growth. These toxins are undetectable without laboratory tests and may be present at dangerous levels without obvious mould in the grains. The risk of feeding brewers grains probably outweighs any potential benefit.