Agrain flaker (also oat rollerorflaking mill) is a tool for flattening whole-seed cereal grains. When this is done with oats, the seed form, called groats, becomes a foodstuff called rolled oats. Whole grains store longer but cereals are usually cooked before consumption by humans; the rolling process significantly decreases cooking time.[1] Spelt and wheat can also be rolled.[2] Grains other than oats may need to be softened before they can be rolled.[3] Oat rollers work by flattening the grain against a rolling cylinder.[1] It is possible to build a home-scale manually cranked flaking mill.[4] Oats can also be flaked using a rolling pin or a pasta press.[5]
Using a grain flaker to produce rolled oats for horse feed may decrease horse indigestion compared to feed composed solely of groats.[6]