With oats, you have choices: whole, cut, or rolled. No matter what shape it takes, a hearty bowl of oatmeal in the morning gives you a wholesome start to your day.
Oat Groats
Groats are whole oat kernels that have had their hard hull removed but are otherwise intact. They are available in health food stores and in the natural food section of some very large supermarkets. Although you can cook them for breakfast, it takes a long time and, like any whole grain, they will remain chewy when tender. They will never become the soft, porridge-like cereal you are probably familiar with. It is possible to find crushed oat groats, which are quicker and easier to prepare and have a grainy texture similar to that of other hot wheat and rice cereals you may be familiar with.
Steel-Cut Oats
If you buy oatmeal important from Ireland or Scotland, you are probably buying steel-cut oats. The difference between this European style of oat processing and American rolled oats is that steel-cut oats are groats that have been cut into tiny pieces while rolled oats are groats that have been steamed and then pressed flat with rollers and flaked.
Rolled Oats
The oatmeal varieties you think of as "old-fashioned," "instant," and "quick" are all forms of flaked, rolled oats. Old-fashioned style oat flakes are thicker than "quick," and "quick" oats are thicker than "instant." The thicker the flake, the longer it takes to cook.
Oat Bran
When groats are milled to make commercial brand of oat flour, the bran is separated out from the kernel. Oat bran is sold separately from oats as a high-fiber cereal and ingredient used in baked goods.
Cooking Times
It takes about 45 minutes to fully cook oat groats. You can soak groats overnight in water to cover to cut back on cooking time in the morning. When pre-soaked, groats cook in 15 to 20 minutes. Steel-cut oats must cook for about 30 minutes. Old-fashioned oats usually cook in about 5 minutes; quick-cooking oats take just 1 minute and "instant" oatmeal is cooked as soon as you stir in boiling water or milk. Depending on the grind, oat bran takes from 2 to 5 minutes of cooking to cook to a creamy texture.
Benefits
If you have the time and patience to cook oat groats, and you enjoy the texture, groats are a highly nutritious, minimally processed, whole-grain food that can be used not only as a breakfast cereal but as a grain side dish at lunch or dinner, in place of or mixed with other starchy foods such as rice or whole wheat berries. If you happen to own your own stone mill (and yes, there are grain mills made for home use!), you can also grind oat groats into oat flour. Steel cut oats can also be soaked to reduced cooking time and they can also be ground into oat flour. The benefits of all other varieties of oats are clearly time and convenience. The nutritional value is similar among all types of oats, although quick and instant varieties usually contain less fiber. Some commercial brands of rolled oats are fortified with added vitamins and minerals. The soluble fiber found in all varieties of oats, and especially concentrated in oat bran, may help reduce blood levels of cholesterol, thereby reducing your risk of developing atherosclerosis (hardening of the arteries) and related heart disease.
Sources:
The Cook's Thesaurus: Oats Web 12 May 2011
http://www.foodsubs.com/GrainOats.html
