Chili season is here, and few things stretch a grocery budget like a bag of dry beans. One pound of dry beans makes about 6 cups cooked, according to University of Maine Cooperative Extension. A drained 15½-ounce can holds about 1¾ cups. That means one bag replaces roughly three and a half cans.
Dry beans also keep. Stored in a cool, dry spot in a sealed bag or covered non-metal container, they last up to a year, UMaine says. That makes them a natural fit for a well-stocked pantry.
But there is one mistake home cooks make every fall, and it can make the whole family sick.
The kidney bean rule
Raw and undercooked red kidney beans contain a natural toxin called phytohaemagglutinin, also known as kidney bean lectin. According to Ohio State University’s Chow Line column, which draws on the FDA’s “Bad Bug Book,” eating as few as four or five improperly cooked red kidney beans can cause illness.
The symptoms are not subtle. Severe vomiting usually starts within a few hours, followed by diarrhea. Some people have needed hospital care, though most start feeling better within three to four hours after symptoms begin.
The good news is that proper cooking destroys the toxin. Ohio State reports that raw red kidney beans contain 20,000 to 70,000 units of the lectin, while fully cooked beans drop to 200 to 400 units, a level not considered a problem. White kidney beans, or cannellini, carry about one-third as much as red kidney beans. Fava beans carry 5 to 10 percent as much.
Why the slow cooker is the problem
Here is the trap. Many people dump dry beans straight into a slow cooker, set it on low and walk away. Ohio State warns against using a slow cooker for raw kidney beans, because it likely won’t get the beans hot enough to destroy the toxin.
Research shows the toxin is destroyed at 212 degrees Fahrenheit, a full boil, held for 10 minutes. Scientists recommend boiling for 30 minutes to make sure the beans get hot enough for long enough.
The FDA guidance cited by Ohio State spells out three steps for dry red kidney beans:
- Soak the beans in water for at least five hours.
- Drain and discard the soaking water.
- Boil the beans in fresh water for at least 30 minutes.
Once the beans are cooked and tender, you can finish them in the slow cooker with your chili or soup. UMaine Extension says beans may be simmered with other ingredients in a crockpot after they are cooked and tender.
A simple way to cook any dry bean
You do not need to be a chef to cook beans from scratch. Here is the basic method from UMaine and University of Nebraska-Lincoln Extension:
- Sort and rinse. Spread the beans on a clean towel and pick out stones and shriveled beans. Rinse them in a strainer under cold water.
- Soak. For an overnight soak, cover 1 pound of beans with 10 cups of water and refrigerate 6 to 8 hours. For a quick soak, bring 1 pound of beans and 6 cups of water to a boil for 2 to 3 minutes, take it off the heat, cover and let it sit at least an hour. Nebraska Extension calls its hot-soak version the preferred method. Lentils, split peas and black-eyed peas do not need soaking.
- Drain and rinse. Always pour off the soaking water.
- Simmer in fresh water. Bring to a boil, then lower the heat. Nebraska Extension lists approximate times of 60 to 90 minutes for black beans and 90 to 120 minutes for kidney, navy and pinto beans.
A few tips make a big difference. Hold off on tomatoes, vinegar, lemon juice or wine until the beans are tender, because acid can keep them from softening. Nebraska Extension also advises against adding baking soda, which destroys thiamin, a B vitamin, and can give beans an off flavor.
If you own an electric pressure cooker, Nebraska Extension says unsoaked kidney beans take about 20 to 30 minutes at pressure, followed by a 20-minute natural release. Follow your manufacturer’s directions, since models vary.
Cook once, eat all month
Beans freeze beautifully. UMaine recommends packing cooked beans in 1- or 2-cup portions, which keep 3 to 4 days in the refrigerator or up to 6 months in the freezer. Nebraska Extension advises freezing extras within 4 days of cooking. Thaw them in the refrigerator and use them just like canned beans.
That means one Saturday afternoon of cooking can stock your freezer with ready-to-use beans for weeks of chili, soups, burritos and rice bowls.
The bottom line
Dry beans are one of the cheapest, longest-lasting foods you can keep in a self-reliant kitchen. One pound does the work of three and a half cans, and a bag in the pantry can wait up to a year.
Just remember the one rule that matters most: soak, drain and give red kidney beans a hard boil before they ever see the slow cooker. Do that, and your chili will be safe, hearty and easy on the wallet.
Sources
- Ohio State University CFAES, Chow Line: Dry kidney beans need to be boiled
- University of Maine Cooperative Extension: How to Store and Cook Dried Beans
- University of Nebraska-Lincoln Extension: How to Cook Dry Beans From Scratch