What are rolled oats? What are steel cut oats? What's the difference between quick and instant oats?
I get these questions about oats a lot and hopefully I can answer them here. There are 5 main types of oats, plus oat bran and oat flour.
The first type, is the whole oat or oat groat. It is the whole oat kernel with the outer hull removed. They take the longest to cook of all the oats; taking about 50 minutes, with some recipes calling for them to be soaked overnight. These oats are very chewy and have a strong nutty flavor.
Then there are steel-cut oats. Theses are whole oats that have been cut down in size (to about a third) with steel blades. Since they are smaller, they take less time to cook than the whole oats but are longer than the rolled oats.
Next there are rolled oats, of which there are 2 types, thick and regular. Both are the whole oat that is steamed and rolled flat, the difference is how thick the flake is. The thicker the flake, the longer it will take to cook (but not by much). The difference here would be in texture of the thick and regular oats in what your cooking. These are also the oats generally eaten raw, like in granola or trail mixes. They can also be used in recipes for breads and cookies.
Next in line are the quick oats, these are whole oats that have been cut (not necessarily steel cut) in pieces, then steamed and rolled into flakes. This reduces their cooking time (they take anywhere from 3-8 minutes), and makes them great for recipes, like cookies or muffins.
Finally we come to instant oats. These are quick oats that have been precooked, so all you need to do is add hot water. Usually there is sugar pre-added to them as well for flavor. There is almost no cooking time required for instant oats, just add hot water and you're good to go. They are also a healthy replacement for breadcrumbs
There is also oat bran and oat flour. Oat bran is the whole oat that has been ground into a meal, or tiny pieces where as the oat flour is usually cut oats (like the steel cut) that have been steamed and ground into a powder.
Having said all this, that doesn't mean you have to run out to the store to buy instant or quick oats. If you only have rolled oats, you can make your own quick oats by chopping them up in a blender or make your own oat flour as needed, see my earlier video post on that here.
The smaller the oat size, the faster it will cook, and should be interchangeable when moving down the list. For example, you can substitute chopped rolled oats for quick oats, but you won't necessarily be able to sub quick oats for rolled in a recipe.