Steel-cut oats, or Irish oats: Groats that have been chopped into small pieces. They have a firmer texture than rolled oats. Steel-cut oats have a mild flavor & a starchy texture; and can be substituted for rice in pilaf or risotto or used as a delicious topping for salads
Rolled oats, or old-fashioned oats: Commonly called oatmeal These are oat groats that are steamed and flattened with huge rollers so that they cook quicker, in about 5 to 15 minutes. They are a great binder for meat loaf and can be used in stuffing for chicken or turkey.
Quick oats: These are groats that have been cut into several pieces before being steamed and rolled into thinner flakes, thus reducing the cooking time to 3-5 minutes. While they cook quicker, any oat aficionado will tell you that they lack the hearty texture and nutty flavor of the less-processed varieties.
Instant oats: These are made by chopping groats into tiny pieces, precooking them, drying them, then smashing them with a big roller. They need only be mixed with a hot liquid. They usually have flavorings and salt added. All of this processing removes all traces of the original texture and rich flavor of the groats.
Oat flour: Oat flour is made from groats that have been ground into a powder, and contains no gluten so it does not rise like wheat flour. It can also be made at home by grinding rolled oats into a powder in a blender. It has a delicate texture that will produce moist & tender baked goods.
Note: If purchasing in the bulk section, make sure that the bins containing the oats are covered, free from debris, and that the store has a good product turnover to ensure its freshness. Smelling the oats will tell you if they are fresh. Store in an airtight container in a cool, dry and dark place where they will keep for approximately two months.