Hafragrautur

Oatmeal is a preparation of oats that have been de-husked, steamed, and flattened, or a coarse flour of hulled oat grains that have either been milled (ground), rolled, or steel-cut. Ground oats are also called white oats. Steel-cut oats are known as coarse oatmeal, Irish oatmeal, or pinhead oats. Rolled oats were traditionally thick old-fashioned oats, but they can be made thinner or smaller and may be categorized as quick oatmeal or instant oatmeal depending on the cooking time required, which is determined by the size of the oats and the amount of precooking. The oat grains are de-husked by impact, and are then heated and cooled to stabilize the groats, the seed inside the husk. The groats may be milled to produce fine, medium, or coarse oatmeal. Rolled oats are oats that have been steamed, flattened by a "flaking roller", and dried. Old-fashioned oats are made from whole oat groats and may be thick and require longer cooking time. Quick-cooking rolled oats are made from steel-cut oats and rolled somewhat thinner. Instant oatmeal is made from more finely cut oats and rolled even thinner, often with a sweetener and flavorings added.

Source: Wikipedia