They take about 15 minutes to cook. Quick cooking rolled oats are groats that have been cut into several pieces before being steamed and rolled into thinner flakes. Though they cook in about 5 minutes, many think the flavor and texture are never quite as satisfying as with regular rolled oats. Instant oats, however, are not interchangeable because they're made with cut groats that have been precooked and dried before being rolled. This precooking process so softens the oat pieces that, after being combined with a liquid, the mixture can turn baked goods such as muffins or cookies into gooey lumps.
Most instant oatmeal is packaged with salt, sugar and other flavorings.
Scotch oats or steel-cut oats or Irish oatmeal are all names for groats that have been cut into 2 to 3 pieces and not rolled. They take considerably longer to cook than rolled oats and have a decidedly chewy texture. Oat flour is made from groats that have been ground into powder. It contains no gluten, however, so for baked goods that need to rise, like yeast breads must be combined with flour that does. Oat bran is the outer casing of the oat and is particularly high in soluble fiber, thought to be a leading contender in the fight against high cholesterol.