Do I Need to Soak My Grains?

small piles of 25 different whole grains such as different rices, corn, wheat berries, millet, and others.
Photographs: Above, cereals collection from Shutterstock; others, Robyn Lee
small piles of 25 different whole grains such as different rices, corn, wheat berries, millet, and others.
Photographs: Above, cereals collection from Shutterstock; others, Robyn Lee

"Do I Need to Soak Grains?"

"Many grains take a long time to cook and I've heard soaking them overnight can shorten this time or produce better end results. Is it true?"

I loved eating steel-cut oatmeal as a kid, but I've rarely made it as an adult because frankly, by the time I'm thinking about breakfast, I'm way too hungry to wait the half-hour for it to cook. On the surface, the idea of soaking the oats in water overnight to speed up their cooking time seems logical enough—but does it work?

The Test

Grains that you buy at the store are typically treated in one of three ways: Whole grains have had only their inedible husk removed, leaving behind the bran, germ, and endosperm layers. Think of them as something like shelled, skin-on nuts. Polished grains like pearled barley or white rice have had most of their bran layer removed. Cut grains like oatmeal are whole grains that have been chopped into smaller pieces for faster cooking.

How would each of these three types of grains fare with and without an overnight soak? To find out, I soaked whole-grain barley, pearled barley, and steel-cut oats overnight, with and without salt, then cooked them side-by-side with grains that hadn't been soaked first.

As it turns out, there's not all that much logic to the results.

The Results

Whole-Grain Barley

Whole-grain barley cooked three ways: not soaked (left), soaked without salt (center), and soaked with salt (right).

Whole grains are the holy (whole-y?) grail of the health-food set. The trouble with them is that the layer of bran surrounding each grain acts as a barrier, slowing down the rate at which water can penetrate to the center, so they can take a while to cook. The good news is they're hard to overcook—the bran retains a pleasant chewy texture even after prolonged cooking. (For more on whole grains, check out our handy guide.)

So, how did soaking affect their cooking time? Actually, not too much. The whole-grain barley soaked overnight cooked up the next day in 35 minutes (salting made no difference in timing or texture), while the cooked-from-dry grains took only five minutes longer. Flavor-wise, there wasn't much difference.

The verdict? Don't bother soaking whole grains—the payoff is barley worth the effort. (Yup, I just wrote that.)

Polished (Pearled) Barley

Cooked polished barley. The grains that weren't soaked overnight (at left) retained their bright beige color, while the soaked ones (center and right) turned gray but cooked more quickly.

The first thing I noticed after soaking the pearled barley overnight was that it had changed color, from a light beige to a murky gray. As you can see in the photo above, the two examples of soaked pearled barley are gray, while the un-soaked one remained beige throughout cooking. As for cooking times, the soaked ones, both with and without salt, were ready in just half the time, 15 versus 30 minutes. Despite the color differences, the flavors of all the batches were comparable.

Moral of the story: So long as you don't mind off-colored, drab-looking grains, pre-soaking pearled barley can save you some cooking time.

Steel-Cut Oatmeal

All three versions of the steel-cut oats cooked at the same rate. The differences in texture seen in the photo are the result of using different pot sizes to cook each one (the widest pot, at left, provided more surface area for the water to steam away).

Based on the first two tests, I was fully expecting the oats to follow the trend of cooking faster after a good soaking: While they're technically a whole grain, steel-cut oats have been chopped into tiny pieces, exposing plenty of inner-grain surface area for the water to penetrate without having to go through the bran. To my surprise, the oats all cooked up into creamy oatmeal in 35 minutes, irrespective of soaking and salting. Guess I'll be sticking with eggs as my quick-cooking breakfast staple.

What does this mean?

Well, mainly that soaking grains isn't necessarily going to speed things up, and salting doesn't seem to make a (salt-)lick of difference. And when soaking does help, as in the case of pearled barley, it doesn't always look pretty. If you don't care about appearances and are desperate to knock 15 minutes off the time it takes to cook polished grain, go for it. I, for one, will just accept my grains as they are and wait patiently for them to do their thing.

That, or I'll reach for something I know will work: my pressure cooker.