Oats are the third leading cereal crop produced in the United States (after wheat and corn) and the fourth most important crop world-wide. They were once considered a weed which grew right with the barley and wheat. One day farmers decided to "join 'em rather than fight 'em," and oats started being planted as a crop by itself. It fares best in cool, moist climates, which is why they are such a popular staple of the British Isles like Scotland, Ireland and Wales. The grain was introduced into the Americas in 1602 by a sea captain who planted them in one of the islands off the coast of Massachusetts.
Whole Oats, and Whole Oat Groats mean the same thing. They have been minimally processed with only the outer hull removed. To prepare Oat Groats - Use two cups liquid -- water -- and bring to a boil. Add one cup of oat groats and lower heat, simmer for about 50 minutes. Soaking overnight before cooking is advised.
Steel-cut (or Irish) Oats: Whole groats chopped into two or three pieces so they cook more quickly. Chewy and nutty, they cook in about 15-20 minutes and make a fantastic breakfast porridge.
Rolled Oats: Whole oat grains that have been heated and rolled flat. Their greater surface area helps them cook in about 5 minutes. Also called "old-fashioned" oats, rolled oats are best for most baked goods.
Quick Oats: Oats that have been sliced and rolled so that they cook in just one minute.