The oats that most of us in the U.S. eat are rolled oats. These are oats such as the familiar Quaker Old-Fashioned Oats. But, increasingly, different varieties of oats are showing up on grocery store shelves. You may have seen steel-cut, Irish, or Scottish oats.
Steel-cut, Irish, and Scottish are all the same type of product. Examples are McCann’s Irish Oatmeal and Bob’s Red Mill Steel-Cut Oats. As well, Quaker now sells a steel-cut oats.
Both rolled and steel-cut oats consist of the entire oat grain, often called groats. Regular rolled oats are often called old fashioned oats or regular oats. These are oats that have been steamed and then rolled between heavy rollers to flatten the grains and make them easier to cook, in process called flaking.
Quick cooking oats are rolled oats that have first been cut into smaller pieces before being steamed and rolled. These pieces will be around one-fourth to one-third the size of a whole groat, to give cooking times of about five minutes. Regular oats, on the other hand, require from ten to fifteen minutes for most people.
Old fashioned and quick cooking oats are usually interchangeable in recipes and besides cooking time, only the texture is a bit different, with old fashioned oats having a bit more chew and a rougher texture which some people prefer. However, in situations where the oats will have to stand for a long period of time, such as on a steam table in a cafeteria, old fashioned oats should be used, as the smaller pieces in quick cooking oats will not stand up to the prolonged exposure to heat, lasting only about one hour before becoming too mushy, whereas regular oats can stand up for at least three hours. Thicker oats, rolled between rollers with more space between them, could presumably hold up longer in such conditions, but I personally would not trust an establishment that felt it needed to hold cooked oats for longer than three hours at a time. Steel-cut oats, covered below, would hold up just as well as regular oats.
Instant oats should not be confused with old fashioned or quick cooking oats. These are oats that have been flaked and then pre-cooked or gelatinized to reduce cooking time substantially by enhancing water penetration and causing the starch to gelatinize more quickly. The particles are very fine and the texture is not chewy at all compared to regular or quick cooking oats. Nutritionally, regular and quick cooking oats are the same, but instant oats may be digested and metabolized more quickly by the body, causing a faster rise in blood sugar, which is called the glycemic response. Instant oats should not be substituted for regular or quick cooking oats in recipes. They are only suitable for a quick breakfast.
Steel-cut, Irish, or Scottish oats are simply whole oat groats that have been cut into pieces, usually only two or three. They are not steamed or rolled and so require the longest cooking time. Although they are not more nutritious than regular rolled oats, they do have a chewier, hardier texture that some people prefer. Once added to boiling water, (about a 3:1 ratio) they will take about 20 to 30 minutes to cook up, depending on your taste. If you want to make oats in your slow cooker so you can have them ready in the morning, then steel-cut oats are the way to go.
Some steel-cut oat companies, in their ads, will talk about all the natural nutrients in steel-cut oats, and imply, if not actually say, that they are more nutritious than rolled oats, but nutritional analyses does not support this. The only criteria for choosing rolled or steel-cut oats is personal preference. Personally, I prefer steel-cut because I like the chewier texture, but I rarely want to devote the time to it.
This article contains one or more Amazon affiliate links. See full disclosure.