The biggest reason to roast is mold or mildew on the grain from harvest. High roasting temperatures kill mold and mildew spores before the grain is mixed with Vitamins, Minerals and bagged. Mold growth reduces feed value. When the horse refuses to eat for no apparent reason, the grain could have a moldy or mildew smell that we cannot
detect. Some signs of mold in feed are: dustiness, caking of feed, darkening of feed, poor feed flow out of bins, refusal to eat for no apparent reason, moldy or mildew smell.
Roasting also has an advantage in speed of processing and produces a dry product that can be stored without deterioration due to moisture. Mold germinates at temperatures as low as 45°F, with most rapid growth at 75° to 90°F. Mold requires humidity or moisture for germination, therefore, an upper limit of 14.5% moisture is recommended for stored corn or milo. Other grains should maintain moisture levels less than 13%. Roasted grain has moisture levels at 10% or less.