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What beans should not be cooked in a slow cooker?

Slow cookers are a convenient way to cook beans, allowing you to simply add beans, water, and seasonings and let the beans simmer away hands-free for hours. While most types of dried beans can be successfully cooked in a slow cooker, there are a few varieties that don’t turn out quite right when prepared this way.

Kidney Beans

Kidney beans, including red, white, and cannellini varieties, are one of the types of beans that should not be slow cooked. Kidney beans contain a toxin called phytohaemagglutinin that can cause extreme nausea, vomiting, and diarrhea if consumed. This toxin breaks down when the beans are boiled for at least 10 minutes, but the lower temperature of a slow cooker may not get hot enough to destroy the toxin completely. For this reason, dried kidney beans should always be boiled on the stovetop first for 10-15 minutes before adding to a slow cooking recipe.

Fava Beans

Fava beans, also known as broad beans, are another variety that you’ll want to avoid cooking in the slow cooker from start to finish. Like kidney beans, fava beans contain compounds that can cause illness if they aren’t properly prepared. Soaking fava beans overnight and then boiling them for at least 10 minutes is recommended to deactivate the compounds before adding them to a slow cooker dish.


Soybeans typically don’t turn out well when cooked in a slow cooker. The long, slow cooking can cause soybeans to become mushy and lose their shape. Soybeans are also difficult to fully hydrate and soften using just the steam environment of a slow cooker. It’s best to avoid cooking soybeans in a slow cooker and instead boil or pressure cook them.

Small Beans

Very small bean varieties like lentils, split peas, and black-eyed peas don’t require presoaking before cooking. However, the low heat and slowed evaporation of a slow cooker often leads to mushy, overcooked small beans. It’s usually better to prepare these bean types through boiling, pressure cooking, or sautéing instead.

Preparing Safe Beans in a Slow Cooker

While some beans are off limits for slow cooking, most varieties still turn out well when prepared properly in a slow cooker. Here are some tips for safely cooking beans in a Crockpot:

  • Always sort through dried beans to remove any debris or damaged beans.
  • Soak beans overnight, or do a quick boil for 1 minute before adding to the slow cooker.
  • Discard the soaking water, as it can contain the indigestible sugars that cause gas.
  • Don’t cook kidney beans or fava beans fully in a slow cooker. Always boil for 10+ minutes first.
  • Add acidic ingredients like tomatoes, citrus juice, or vinegar at the end to prevent tough beans.
  • Make sure beans are fully submerged in liquid the entire time.
  • Don’t lift the lid unnecessarily, which lets heat escape.
  • Cook beans on low for 7-8 hours or high for 4-5 hours.

The Best Beans for Slow Cookers

Most types of beans turn out perfectly cooked, flavorful, and intact when slow cooked. Here are some of the best bean varieties to use:

Bean Variety Notes
Black beans Trendy, nutritious beans perfect for Latin dishes.
Pinto beans Mild beans great for tacos, dips, soups.
Garbanzo beans Also called chickpeas. Use for hummus.
Navy beans Small white beans for classic baked beans.
Great northern beans Large, versatile white beans.
Cranberry beans Speckled beans that hold their shape well.

Tips for Cooking Beans in a Slow Cooker

Follow these tips and bean slow cooker recipes to end up with tender, flavorful beans every time:

Flavor the Cooking Liquid

The liquid is going to flavor the beans as they cook, so skip plain water and use vegetable or chicken broth instead. You can also add sautéed aromatics like onion, garlic, and spices to the liquid.

Brown Beans First

Browning the beans in oil or bacon fat first adds richness and enhances the bean flavor.

Add Acidic Ingredients Later

Don’t add tomato sauce, lemon juice, vinegar, or other acidic ingredients early on, as they will prevent the beans from softening fully. Stir them in 30-60 minutes before serving.

Check Seasonings Before Serving

The flavors in the slow cooker will concentrate over the long cooking time. Check seasonings like salt, pepper, herbs, and spices and adjust to taste at the end.

Make Beans the Star

Simple bean dishes like cumin black beans, Tuscan white beans, or smoky baked beans are inexpensive, nutritious meals.

Use Beans in Hearty Soups

Beans pair perfectly with slow cooked soups, adding protein, texture, and fiber.

Purée Beans for Dips

Puréed white beans become instantly creamy for bean dips and spreads.

Slow Cooker Bean Recipes to Try

Here are some delicious slow cooker bean recipes to add to your meal planning:

1. Slow Cooker Chili

This classic chili gains richness from a combo of pinto and kidney beans simmered in a spices tomato sauce. Top with cheese, onions, and cilantro.

2. White Chicken Chili

Chicken and cannellini beans make this chili a lighter, yet still hearty option. Finish with lime and cilantro.

3. Slow Cooker Red Beans and Rice

New Orleans-style beans get perfectly tender and flavorful after a slow cook. Serve over rice for a complete meal.

4. Cuban Black Beans

Warm spices like cumin, oregano, and garlic infuse these easy black beans. Spoon them over rice or stuffed in tortillas.

5. Baked Beans

Sweet and smoky baked beans with bacon are summer BBQ perfection. They’re also great any time of year straight from the slow cooker.

6. Slow Cooker Refried Beans

Cook pinto beans until very soft, then mash them with onions, garlic, and seasonings for easy homemade refried beans.

7. White Bean and Roasted Garlic Dip

Purée cannellini beans with roasted garlic, lemon juice, and olive oil for a quick appetizer or snack.

8. Slow Cooker Minestrone Soup

Load up this Italian vegetable soup with beans plus pasta or rice to make it more substantial.

9. Ham and Bean Soup

Smoky ham and creamy white beans create a comforting soup for chilly weather. Use great northern, navy, or cannellini beans.

10. Slow Cooker Lentil Soup

Cozy lentils and veggies get better the longer they simmer. Finish with lemon and parsley.

Common Slow Cooker Bean Problems and Solutions

Even when following the proper preparation methods, beans can sometimes turn out undercooked, mushy, or bland when made in a slow cooker. Here are some common bean issues and troubleshooting tips:

Beans Aren’t Softening

  • Older, dried out beans may never soften fully. Use fresh beans.
  • Fully cover beans with water. Cook on high if on low isn’t working.
  • Add a teaspoon of baking soda to help soften the beans.
  • Make sure the slow cooker reaches a full simmer.

Beans Are Mushy

  • Don’t cook beans over 8 hours on low or 6 hours on high.
  • Skip soaking beans beforehand to reduce moisture content.
  • Cook beans without the lid on to allow evaporation.
  • Try using less cooking liquid next time.

Beans Lack Flavor

  • Use well-seasoned cooking liquid like broth or aromatics.
  • Brown beans first for more depth.
  • Add more herbs, spices, garlic, etc. at the end.
  • Stir in a splash of vinegar or splash of hot sauce before serving.

Beans Cause Digestive Issues

  • Always boil kidney beans and fava beans first before slow cooking.
  • Discard soaking water after prepping beans.
  • Add a strip of kombu seaweed to cook with beans to reduce gas.
  • Introduce beans slowly into your diet to allow adjustment.


While slow cookers make cooking dried beans simple, there are a few key varieties that should be avoided or pre-boiled before adding to the slow cooker. Kidney beans, fava beans, soybeans, and small beans like lentils and split peas don’t always turn out right when slow cooked. Taking proper preparation steps like presoaking, pre-boiling, and using well-seasoned cooking liquid results in tender, flavorful beans from a slow cooker. Follow recipes for dishes like hearty bean soups, spicy chilis, and creamy bean dips to take advantage of the convenience of slow cooker beans.