Home » A guide to oats: The different types and how to cook and eat them

A guide to oats: The different types and how to cook and eat them

Will it ever not be time for oatmeal? Unlikely.

Oats are one of the simplest, most versatile and inexpensive ways to get your fill of the whole grains we all know we’re supposed to be eating. As Harold McGee explains in “On Food and Cooking,” oats are actually the grains of the grass known as Avena sativa. While the hull is removed, the rest of the grain — the coarse outer bran, the carb-laden endosperm interior (the source of refined flour in wheat grains) and the fat-containing germ — remains.

The nutritional benefits of oats are in part thanks to fiber and protein, but they also contain beta-glucans. These indigestible carbohydrates absorb and hold water, lending oatmeal its smooth and thick consistency, and help lower cholesterol, McGee says. If they come from a certified facility and the packaging notes it, oats can also be acceptable for those with celiac disease or other gluten-free needs.

In the about-to-be-released “Mother Grains: Recipes for the Grain Revolution,” author and chef Roxana Jullapat says that oats were probably first cultivated tens of thousands of years ago in the Near East and domesticated in the Bronze Age. They became a major crop in Northern Europe and spread to America in the 17th century. Even so, oats weren’t widely valued for human consumption, as indicated by this quippy definition by 18th century English writer Samuel Johnson in his famous dictionary: “A grain, which in England is generally given to horses, but in Scotland supports the people.” (In modern times, upward of 90 percent of the crop still is used as animal feed.)

In America, oats really took off in the 1850s after German immigrant Ferdinand Schumacher developed a method for rolling the oats with heavy steel pins at his mill in Akron, Ohio, according to author and pastry chef Stella Parks in “BraveTart: Iconic American Desserts.” The grain ended up “amassing a faithful following during the years of the Civil War.” Other producers, including the Quaker Mill Company, jumped on board, with several mills merging into the American Cereal Company in 1891, retaining the smiling mascot of a man in Quaker garb.

You’ll never hear me dissuade you from your standard bowl of oatmeal in the morning, but consider expanding how you cook the oats and what type you use. (Each type is identical in nutrition when compared at equal weights.) “They’re never the flashiest grain, never used to make the sexiest dish,” Jullapat says. “They evoke times of hardship and are forever linked to Dickensian images of a famished Oliver Twist, pleading for a second bowl of gruel. … But don’t be mistaken — oats have fueled civilizations, celebrated the supernatural, and in modern times even replaced milk. Our tendency to relegate oats to a microwave porridge overlooks the myriad ways in which they can be consumed.”

Let’s break down the advice and ideas by type of oat.

Oat groats. Groats are the entire kernel of the oat, with just the inedible husk removed. Even after soaking and cooking, they remain chewy, Jullapat says. On the stovetop, they will take on the longer side to cook, about 30 minutes according to this method by Bob’s Red Mill. The company suggests using oat groats much as you would any other whole, chewy grain, such as rice — in grain bowls, stews and salads, for example.

If you buy oat flour, you’re getting ground oat groats. “Oat flour, with its high bran content, often translates into tender and moist baked goods,” Jullapat says. “Its nutty taste and soft feel are similar to that of whole wheat, without the added gluten.” In “The Science of Good Food,” David Joachim, Andrew Schloss and A. Philip Handel recommend not using more than 5 to 20 percent oat flour in your bread, cake and cookie recipes. Parks notes that grinding old-fashioned oats at home is not a good substitute for commercial oat flour, which is finer and includes the other parts of the grain that serve a nutritional and thickening purpose.

Steel-cut oats. These are oat groats that have been cut into several pieces for slightly quicker cooking, 20 to 30 minutes on the stovetop. Some brands offer quick-cooking steel-cut oats to trim even more time. “Porridge made with steel-cut oats has an earthy, wholesome taste and a pleasantly chewy texture,” Jullapat says. (You can use them in cold overnight oats, too.) That hardiness, though, is one reason they’re typically not used in baked goods, where they can be too tough. One exception: This Chocolate Coconut Porter Cake, which I tested years ago, and boasts distinctive nubs of oats embedded in the tender crumb.

The recommended ratio of liquid to steel-cut oats can vary, but it tends to fall in the range of 3 to 4 parts liquid to 1 part oats. I favor 3-to-1. As with all these, it’s not a bad idea to consult the package instructions first.

My favorite way to cook steel-cut oats, in the Instant Pot, gets around the longer cook time. For a quick fix, I’ll pressure cook them for 9 or 10 minutes, but for a hands-off approach and luxurious feel, I slow-cook them overnight to have a warm batch ready in the morning. Of course, this can be done in a traditional slow-cooker as well.

Old-fashioned rolled oats. Also known as the versatile, easy-to-cook variety I buy in 10-pound packages from Costco. If you were only going to keep one type of oat in the house, this should be it. Old-fashioned oats are steamed and then rolled, which dramatically speeds up the cooking process — about 5 minutes on the cooktop and even less in the microwave. (Some brands sell thick-cut rolled oats, which need a little more time to cook.) Regardless of which method you use, I have learned from hard-earned experience that, somewhat similar to eggs, it can help to slightly undercook the oats. They will continue to absorb moisture and thicken so that by the time they’re cool enough to eat, the oats will be at the right consistency. You can also play around with consistency by tweaking the ratio of liquid to oats: 2-to-1 is typical, though I tend to slightly reduce the liquid (a generous 3/4 cup milk to 1/2 cup oats) to avoid soupy results.

When the weather is warmer and I’m pressed for time, I turn to overnight oats, no cooking required. As Parks explains over on Serious Eats with regard to her oatmeal cookie recipe, the steaming process “pre-gelatinizes the starch, making rolled oats soluble in cold water. That lets them swell up with moisture from the dough, and when grains swell, they soften.” Meaning, your oats soaked in liquid in the fridge will be chewy and not tough. As with cooking rolled oats, there’s plenty of wiggle room with the ratios. After going too long unsatisfied with the excess liquid in a 2-to-1 ratio, I followed a recipe in Jullapat’s book that dramatically reduces the difference by combining 1/3 cup of rolled oats with 1/2 cup liquid. With some chia and flax thrown into the mix, the result is delightfully chewy and soft oats not swimming in tons of extra milk. Our Basic Overnight Oats reverses the mix with 1/2 cup oats and 1/3 cup liquid, resulting in a slightly drier bowl.

Quick-cooking oats. Like their old-fashioned sibling, quick oats are steamed and rolled, but they’re made even thinner. McGee says old-fashioned oats are typically 0.8 millimeters thick, with quick half that thick. Guidance varies somewhat by brand, but generally quick oats will cook in 1 to 3 minutes on the stovetop and roughly the same in the microwave. Of all the varieties, old-fashioned and quick oats are the most interchangeable. Advice differs on whether you can sub quick for old-fashioned in a recipe. My verdict? In a pinch, maybe, but know that you may end up with a different texture than what the recipe intended, especially if the oats are mixed into a batter or dough (notably, Quaker’s famous Vanishing Oatmeal Raisin Cookies offer the option of old-fashioned or quick-cooking).

Instant oats. The more widespread definition appears to apply to oats that have been cut, cooked, dried, steamed and then flattened. But there are also instant oats, such as Bob’s, that are not precooked and are just rolled even thinner than quick-cooking oats. Either way, instant oats can typically be prepared with hot water or milk or briefly cooked in the microwave.

Instant oats are best left to porridge. A word of warning from “The New Food Lover’s Companion” by Sharon Tyler Herbst and Ron Herbst: The “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.”

Note: If you’re concerned about pesticides used in oat harvesting, such as glyphosate, seek out organic oats, which have been found to contain much lower levels, if any.