Soaking and cooking dry beans, step by step

Cooking dry beans takes time but very little skill. The steps below follow the advice of two university extension services, the University of Nebraska-Lincoln (UNL) and the University of Maine Cooperative Extension, with notes from Utah State University Extension. Where they disagree, this guide says so. For red kidney beans, the US Food and Drug Administration's soak-and-boil rule comes first; it is summarized here and explained in the kidney bean guide.

Sort and rinse

Dry beans are a farm product, and a bag can contain the odd small stone, clump of soil or damaged bean. Both extension services start the same way:

1. Spread the beans out. The University of Maine suggests a clean towel, which makes small stones easier to see.
2. Pick out stones, dirt, and any beans that are discolored, shriveled or damaged.
3. Rinse the beans in a strainer under cold running water. Maine suggests rinsing several times.

Why beans are soaked

Soaking does two jobs. UNL explains that it lets the beans take up water, so they roughly double or triple in size, and that it starts to break down the starches that cause gas and discomfort. Water-soaked beans then cook in less time. Because beans expand so much, the University of Maine reminds cooks to soak them in a large pot or bowl.

Whichever method you use, both services say to drain off the soaking water, discard it, and rinse the beans before they are cooked in fresh water. Discarding the soaking water is also part of the FDA's advice for red kidney beans.

Three ways to soak

The extension services describe three methods for a pound of dry beans, which is about 2 cups.

UNL calls the hot soak its preferred method, because it shortens cooking time, helps remove some of the gas-causing substances and gives the most consistently tender beans. It calls the overnight soak the easiest. The quick soak is the fallback when time is short.

Legumes that skip the soak

Not every legume needs soaking. UNL lists lentils, split peas and black-eyed peas as needing none, and the University of Maine says the same of dry peas and lentils. These can be sorted, rinsed and cooked straight away, which makes them the quickest route from a dry bag to a meal.

Simmering on the stove

After soaking, the beans are cooked in fresh water. The two services describe the same basic method:

1. Put the drained, rinsed beans in a large pot and cover them with fresh water. The University of Maine uses about 6 cups for a pound of beans.
2. Bring the pot to a boil, then lower the heat, cover, and simmer gently. UNL stresses a gentle simmer until the beans are tender but firm.
3. Add more water if the beans start to show above the surface.
4. Check for doneness by tasting a bean or mashing one against the side of the pot. The University of Maine suggests starting to check after about an hour.
5. Drain the beans as soon as they are done, unless the recipe uses the cooking liquid.

UNL gives most beans 45 minutes to 2 hours, with black beans at 60 to 90 minutes and kidney, navy and pinto beans at 90 to 120 minutes. The University of Maine table is a little longer for black beans, at 1½ to 2 hours. The kinds guide collects the times in one table. UNL also suggests adding herbs and spices near the end of cooking, so less of their flavor is lost.

Salt, acid and baking soda

On these three ingredients the sources do not all agree, so here is what each says.

• Acid. UNL advises adding acidic ingredients, such as lemon juice, vinegar, tomatoes or wine, only after the beans are cooked, because acid can stop them softening. Utah State University Extension makes the same point about tomatoes and other acids, which slow the uptake of water. The University of Maine also advises against acid during cooking.
• Salt. The University of Maine says not to add salt during cooking, because it slows the process. Utah State takes a different approach: it suggests salting the soaking or boiling water and then discarding that water before cooking, saying the salt helps beans soften evenly and that discarding the water reduces sodium. Both approaches keep salt out of the final simmer, so a cook can season the finished dish to taste either way.
• Baking soda. UNL advises against adding baking soda, because it destroys thiamin, a B vitamin, and can give the beans an off flavor.

Pressure cookers and slow cookers

Pressure cookers. UNL's main advice is to follow the manufacturer's instructions and expect some trial and error with each model. It describes a method for unsoaked beans that keeps at least 2 inches of water above the beans and fills the cooker no more than half full, and it notes that a little oil and salt help the beans hold their shape and reduce foaming. Because models differ, this guide does not repeat cooking times for them.

Slow cookers. Utah State University Extension warns that slow cookers may not get hot enough to cook dry beans properly, and advises boiling the beans on the stove first. For red kidney beans, the FDA's rule of at least 5 hours of soaking and at least 30 minutes of boiling in fresh water applies before they go into a slow cooker. Utah State also does not recommend cooking dry beans in a microwave, because microwaves heat unevenly.

How much dry beans make

Dry beans swell a lot. UNL and the University of Maine both say that a pound of dry beans, about 2 cups, makes about 6 cups of cooked beans. The University of Maine puts it more cautiously for a single cup: 1 cup of dry beans makes about 2 to 3 cups cooked. Both say a drained can of about 15 ounces holds about 1¾ cups of cooked beans.

Cooked beans that will not be eaten straight away should be cooled and refrigerated promptly. The storage guide covers how long they keep and how to freeze them.

Next from the pantry: Raw kidney beans, lectins and cooking beans safely