Cooking Beans 101

What do I need to know about soaking and cooking dried beans?

Through the years, we’ve waffled back and forth about the best way to cook dried beans. Admittedly, we haven’t been consistent: some recipes specify that the beans be soaked before cooking, others do not. Our recommendation? Follow the recipe. Each has been specifically developed for soaked or unsoaked beans and should be prepared accordingly.

Soaking Water
So that being said, for recipes that do soak the beans, we typically recommend a long soak—eight hours to overnight. Quick soaking, or bringing the beans to a boil and allowing them to sit for an hour or two before draining and proceeding with the recipe, works fine at rehydrating the beans, though it can rob the beans of some of their nutritional value (see below).

In recent testing, we’ve found that soaking dried beans in mineral-rich; hard tap water can toughen their skins. Some recipes recommend using distilled water to avoid this issue, but we’ve discovered a simpler solution: adding salt to the tap water, which prevents the magnesium and calcium in the water from binding to the cell walls, and it will also displace some of the minerals that occur naturally in the skins. We found that three tablespoons of salt per gallon of soaking water is enough to guarantee soft skins.

Storing Soaked Beans
If you happen to soak beans and aren’t able to use them immediately, they can be drained, transferred to a zipper-lock bag, and refrigerated for up to four days before being used without ill affect to flavor or texture. We do warn against soaking beans much beyond 24 hours as testing has suggested that they can lose flavor and develop tough skins and a mealy texture.

Does Soaking Beans Affect Nutrition?
Soaking dried beans is necessary for hydration, which accelerates the cooking process. While both slow and quick bean-soaking techniques exist, testing has proven that the heated water used with the quicker methods increases the solubility of water-soluble nutrients, such as calcium, magnesium, thiamine, riboflavin, and niacin. Also, the heat of boiling water breaks down cell membranes within the beans, which speeds the release of water-soluble nutrients. For these reasons, quick soaking tends to leach somewhat more of the nutrients out of the beans than do slow soaking methods.

Foaming Beans
Simmering beans typically produce a frothy cap of foam. It’s innocuous stuff that’s nothing more than tiny pockets of air surrounded by a thin layer of water that are stabilized by proteins exuded from the beans that dissolve in the water. While they won’t harm the beans, we typically skim the foam off for a clearer appearance.

Eliminating Gas from Beans
For some, the greatest obstacle to preparing beans is not the lack of a good recipe but an aversion to the discomfort associated with digestion. The creation of unwanted intestinal gas begins with the arrival of small chains of carbohydrates (called oligosaccharides) into the large intestine. People cannot digest these molecules efficiently, but bacteria residing at the end of the gut do and produce gas as a byproduct. Some sources say that presoaking or precooking beans alleviates gas production by removing these carbohydrates. Our science editor decided to put these theories to the test by measuring the amount of one of the most prevalent small carbohydrates in black beans, stachyose.

His results gave the theories some credence. Beans soaked overnight in water and then cooked and drained showed a 28 percent reduction in stachyose. The precooking, quick-soak, method, consisting of a one-minute boil followed by a soak for an hour, was more effective, removing 42.5 percent of the stachyose. While we have reservations about the quick-soaking method, it might be the best way to prepare your beans if they cause you significant discomfort.

Troubleshooting Hard Beans
Finally, if you’ve cooked your beans for hours and found they failed to soften, chances are they are either old and stale (and will never fully hydrate or soften), the water is too hard, or there’s a acidic element present. Food scientists universally agree that high acidity can interfere with the softening of the cellulose-based bean cells, causing them to remain hard no matter how long they cook. Alkalinity, on the other hand, has the opposite effect on legumes. Alkalines make the bean starches more soluble and thus cause the beans to cook faster. (Older bean recipes often included a pinch of baking soda for its alkalinity, but because baking soda has been shown to destroy valuable nutrients, few contemporary recipes suggest this shortcut.)

But how much acid is too much acid? At what pH level is there a negative impact on the beans? We cooked four batches of small white beans in water altered with vinegar to reach pH levels of 3, 5, 7, and 9. We brought them to a boil, reduced the heat to a low simmer, and tested the beans every 30 minutes for texture and doneness. The beans cooked at a pH of 3 (the most acidic) remained crunchy and tough-skinned despite being allowed to cook 30 minutes longer than the other three batches. The beans cooked at pHs of 5, 7, and 9 showed few differences, although the 9 pH batch finished a few minutes ahead of the 7 pH batch and about 20 minutes ahead of the 5 pH batch. Acidity, then, must be relatively high to have any significant impact on beans. So in real world terms, season with discretion and don’t add a whole bottle of vinegar or wine to your beans until they are tender.

Published in: on April 30, 2009 at 11:24 am  Comments (69)  
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  1. This is a very thought out post! Have you ever cooked beans in a pressure cooker before? It totally expedites the process.

    • I always do! My new favorite kitchen tool

  2. Some basic problems with your chemistry – Adding baking soda will decrease acidity and increase pH – thus pH 9 is more alkaline and pH 3 more acidic. There is no way adding vinegar will increase pH to 9, since it will lower pH because it is an acid?

    • He didn’t say that adding vinegar will increase the pH, he said it will make it more acidic, and that will make the beans stay hard.

      • Well, he DID say “water altered with vinegar to reach pH levels of 3, 5, 7, and 9”, and since neutral water has a pH of 7, there’s no way it can be “altered” with vinegar to reach a pH of 9. Any addition of vinegar will lower the pH below 7.

    • He said PH 3 was most acidic if you reread it. He listed the varying degrees of PH they were cooked, he did not say PH 9 was more acidic.

      • I’m guessing the pH 9 water was naturally hard water which had been left untreated – water is defined as hard if it has a pH of over 8.5. All of the other pH levels were presumably achieved by adding vinegar to this hard water.

    • Also, considering the ph of vinegar is 3, they must have been essentially cooking the beans in vinegar in one of the tests.

    • Making the water more acidic by adding vinegar to the water to bring the pH all the way down to 3 will keep your bean skins from becoming tender and the beans will be more crunchy than creamy on the inside. So if you like a lot of vinegar, hot sauce, wine or other acidic flavorings with your beans, be sure to cook the beans until tender before adding too much acidic ingredient or the skins will remain tough, not tender and the beans will take longer to cook and never reach that magical, perfect creamy texture.
      On the other point, I live in Austin and our lime-treated tap water often has a pH of over 10. So you could increase the acidity of our water, thus lowering its pH to 9, by adding vinegar. Adding more vinegar would further lower the pH.

  3. […] cup or so of verdina beans, softened and simmered in water until […]

  4. What about adsorption

  5. I know this web site provides quality depending content and extra data, is there any other web page which presents these data in quality?

  6. […] the ultimate tough bean skin.  Thank you, fucking science.  Fear not, because food geeks have concluded that adding salt to the soaking water interferes with this chemical romance by allowing weak sodium […]

  7. Thanks! I’v been thinking about switching from canned beans to dried beans, and this has been really helpful. *bookmarked*

  8. […] Cooking Beans 101 | Christopher Kimball Blog […]

  9. Superb blog! Do you have any hints for aspiring writers? I’m planning to start my own blog soon but I’m a little lost on everything. Would you suggest starting with a free platform like WordPress or go for a paid option? There are so many options out there that I’m totally overwhelmed .. Any ideas? Many thanks!

  10. I grew several varieties of beans this summer and last summer. When I soaked them to be cooked, some varieties rehydrated easily and uniformly, while others had up to half of the beans remain hard and small, or partially so. I used the same type of water, etc., for all beans. Our water is only a little hard, and the ph is around 6. I’ve tried adding salt, even to the separated beans that failed to rehydrate, to no avail. Any thoughts on this? Some of the “failed” beans are smaller, but that doesn’t seem to be the determining factor. This also happened one time with some navy beans that I purchased. Thanks for any feedback.

  11. […] Cooking Beans 101″ […]

  12. […] to your liking, 2 to 3 hours, depending on the beans. To shorten cooking time, use one of these two soaking techniques. Add additional salt and pepper to please your […]

    • OR…. get a simple, inexpensive pressure cooker. I’ve used my 6-qt Presto stovetop pressure cooker since 1972-73. The price has only increased a few dollars in 45 years. It has four parts: pot, lid, gasket, rocker. The simpler, the less likely to fail. It has two safety features. I love the soothing rocker sound, I can tell listening from my living room that it’s working at exactly the right temp. The fancier it is, the more expensive and more likely to fail. I always soak them, and change soaking water several times, gets rid of gas. Get a few of Lorna Sass’ books on pressure cooking, her vegetarian one has bean and grain charts inside both covers, and clear explanations.

  13. He is absolutely right.Every tip I have used of his and the chefs on America’s Test Kitchen and Cook’s County show have worked for me. You rock Christopher!

  14. Beans de La Olla Recipe. I cooked 2 lbs Peruvian bean I had them soak everynight. cooked them next day added bay leafs, toward end of cooking added my sautéed bacon, onion, garlic to pot of beans, then added cumin, 2 tbsp salt, 1 tblsp pepper added cooked diced ham (which I sautéed in separate skillet before adding to the beans. . toward the end added chopped fresh tomatoes, and cilantro. They cooked beautifully. Took more like 3 hrs to cook completely. I let them cool off, I put them in Refrig, Next day I took them out of refri, warmed up over the stove took to family gathering lots of compliments tasted delicious. when cleaning up, we noticed the bean broth developed white foam, family insisted they turning bad and to dispose of them, but they smelled good, and no one got sick, I made them with lots of love and I am very consciencious about safety, to avoid even a slight possibility of someone getting sick I reluctantly tossed the leftover. Which we were planning to have the next day. what could of caused this reaction a day after they had been cooked? Were they turning bad or was it some kind of normal chemical reaction. 3 others had taken beans, and there’s did not react like this, but theres were Pinto Beans and cooked differently…just FYI.

    • Just an amateur guess: foam happens with beans, it’s cosmetic only, skim it off if you want. But if you taste it and it tastes sour or “off,” toss them. The only way to really tell scientifically, would be to use a lab, and buying new beans is cheaper.

  15. I know this web site presents quality dependent content
    and additional information, is there any other web page which presents these
    data in quality?

    • Cooks Illustrated

  16. Christopher, when you say…
    “Beans soaked overnight in water and then cooked and drained showed a 28 percent reduction in stachyose.”

    Do you mean the beans were cooked in the soaking liquid? I would be interested in the results if the beans were soaked in plenty of water and then they were rinsed, drained and put in new water half-way in the soaking process. This is how Italians do it and since my family is very sensitive to gas, this is how I do it and we’ve never had any problems. It would be great to get clarification on that statement and get hard data on soaking with a mid-way rinse.



  17. x

  18. Hi,
    I cooked navy beans last week and they did turn out tough. I think it’s more related in my case to letting them dry out to much as the oven cut out but the beans were left in the oven an extra hour. I’ve had better luck with previous batches. As for water hardness that is probably a factor but the water is not hard at all here in Newfoundland.

    I found this data on hardness and ours appears very soft.
    According to the Water Quality Association, water hardness is interpreted as:

    Soft 0 – 1 grains per gallon (gpg)

    Slightly Hard 1.1 – 3.5 gpg

    Moderately Hard 3.6 – 7 gpg

    Hard 7.1 – 10.5 gpg

    Very Hard Over 10.5 gpg

    Canadian Water Quality Association published a list to help Canadians identify their water type. It is a great resource. Please contact your gov or search on line. Some cities were well over 50gpg so maybe yours is too.

    According to the Water Quality Association, water hardness is interpreted as:

    Soft 0 – 1 grains per gallon (gpg)

    Slightly Hard 1.1 – 3.5 gpg

    Moderately Hard 3.6 – 7 gpg

    Hard 7.1 – 10.5 gpg
    Very Hard Over 10.5 gpg

    Our water is 0.4 which is very soft. So I think my problem was over cooking and letting the beans dry out too much. I will be more careful next time and see if that gets me back on track.

    good luck

  19. what to use for cooking pinto beans, so when they are cook, they will look white and not red or brown when finish boiling. thanks

    • I just made some yesterday in my pressure cooker. Pintos will never look white, but they will lose their freckles and look light delicate pinkish. I can’t imagine them looking brown, unless they weren’t cooked in enough water and were exposed to air. Did you cover them with enough liquid? Did you cover the pot with a lid? Did you simmer them, rather than boil at a high heat? They weren’t even brown to begin with when dry. Maybe it was the ingredients in your liquid. If you need really white beans for appearance or milder flavor, choose a white bean. Navy, great northern, cannelini, etc.

  20. Vince Ortega, you cannot make pinto beans white. If you want white beans, I would suggest Great Northern or Cannellinis. 🙂

  21. […]  This recipe requires soaking beans, so you’ll have to prepare a day in advance. Soak the beans at room temperature overnight for 8-12 hours. If you soak your beans and aren’t able to use them immediately, seal them in a zip top bag and pop in the fridge for up to 4 days.  Thank you Christopher Kimball! […]

  22. […]  This recipe requires soaking beans, so you’ll have to prepare a day in advance. Soak the beans at room temperature overnight for 8-12 hours. If you soak your beans and aren’t able to use them immediately, seal them in a zip top bag and pop in the fridge for up to 4 days.  Thank youChristopher Kimball! […]

  23. Any way to tenderize beans in chili if you put the tomatoes, meat and spices in a slow cooker and then 12 hours later the beans are still not tender. More slow cooking, or is it an unredeemable batch? I know that next time I will cook the beans without the crushed tomatoes first.

    • I haven’t tried plain baking soda, but I have tried using “baked soda” that is baking soda that has been heated to drive off the extra carbon dioxide, thereby making it into sodium carbonate (baking soda is sodium bicarbonate,) which is much more alkaline. A scant teaspoon in a pound or two of beans seems to *really* soften the beans, eliminating much of the texture when biting into them and reduces the tartness of the tomatoes. I haven’t tried adding it at the same time as the tomatoes, but it should neutralize the acids somewhat, so you may want to try that.
      I will warn you, it seems to increase foaming for anything I’ve added it to (I’ve added it to sauteed onions and it not only foamed up, but seemed to liquefy them.) I like what it has done for me, for some bean dishes.

      • Sodium carbonate (soda ash, aka washing soda) is poisonous. Do not add it to your food.

      • FDA says otherwise, Elsinormay:
        Quit trying to scare people, it’s unbecoming.

      • Whoa! Sodium carbonate is poison! Yikes!

      • Sodium carbonate is only toxic in VERY large doses. It’s even used in toothpaste. A small amount like that is utterly harmless.

  24. I’m wondering if treating beans with yeast might be something to try, or if it might lead to some undesirable result. Seems like it might do a couple of desirable things, like reducing sugars, possibly breaking down cellulose in cell walls, enrichment of the B vitamins. I would like to get more of the proteins out of the cells to link together so as to get a more meat-like texture.

    Any thoughts?

    • Do you mean baking yeast? I imagine it would make them taste quite different. I wouldn’t risk ruining the beans. The only time I can remember where I have baking yeast and cooked beans meet each other, is in a bread recipe I’ve made with vegan refried beans from a can, with all the other usual bread ingredients and jar salsa. Really good.

      If you’re having that much problem with gas, I wonder if you have a medical issue? Do you have digestive issues with other foods? Are you taking a med that reduces the stomach acid you need to digest food? There are over-the-counter meds that change the surface tension of the gas bubbles in your gut, so you can get rid of it (Ihope that’s delicate enough for a food discussion). Talk to your doctor about it, don’t accept amateur online suggestions.

      Another ingredient you might try adding is some KOMBU to the cooking beans, which helps with gas and also adds umame and minerals. I love sea veggies.

      Of course, the simplest way to reduce gas is to soak dry beans and replace the soaking water several times in a twelve hour (period).

  25. […] best results, soak 1/2-pound of dried beans for 8 hours or overnight. Use 1-1/2 tablespoons salt for 2 quarts of water. Otherwise if you don’t have dried beans or the time to soak them overnight, you can use […]

  26. And I thought I was confused about the issue BEFORE I read the article.

  27. Among our staples in the kitchen is Americas’s Test Kitchen. Ever present. We don’t allways agree but we always respect your input.

  28. Do you only have to soak dried beans? what about Canned or fresh?

    • Soaking canned beans is definitely a waste of time – canned beans have been precooked so soaking does nothing at all to them (the processes that take place when beans are soaked depend on natural enzymes present in the beans which are activated by the water, essentially starting the sprouting process, but cooking destroys these enzymes). Not sure about fresh beans, though.

  29. […] you want more detailed information about the science of cooking beans, check out what Christopher Kimball has to say about […]

  30. […] chefs over at America’s Test Kitchen have a great article on cooking beans and the possible problems and […]

  31. […] checked for small rocks) in a large pot with about a cup of water- filtered, because hard water has minerals that interfere with the softening of the skin.  The celery and garlic I added to the saute pan with the root […]

  32. How does soaking beans in water with baking soda added compare to soaking beans in a mild brine?

  33. […] checked for small rocks) in a large pot with about a cup of water- filtered, because hard water has minerals that interfere with the softening of the skin.  The celery and garlic I added to the saute pan with the root […]

  34. […] Should I soak dry beans before cooking? If you decide to make beans from scratch (good for you!), depending on the recipe it may be a good idea to soak the beans. Soaking allows the beans to get hydrated and accelerate the cooking process. Typically it is recommended to soak the beans for 8 hours or overnight. Don’t soak beyond 24 hours, as the bean can become mealy, develop tough skins and lose some flavor. If you can’t use them right away, just drain. Transfer to a resealable bag and refrigerate for up to 4 days. Make sure to rinse the beans in cool water first to discard any split beans and dirt, then soak in cool water about 1 part beans to 3 parts water in a cool, dry area or refrigerator. (Source: Christopher Kimball) […]

  35. Epazote (Mexican Herb) will eliminate any gas effect from beans. You can grow this herb yourself, or buy it fresh when in season at your nearest latin store. Fresh epazote sells out quickly. But there is also the dried kind, that you may also purchase. A little goes along ways.

    • Thanks! I’ll try this.

  36. crock pot nuff said.

  37. Reblogged this on An Occasional Knitter.

  38. Personally I just enjoy eating some good beans!I know a quality bean when I eat one😎

  39. Thank you, this confirms my hypothesis that the last bean casserole I made (in which I added all the ingredients — including apple cider vinegar — to the slow cooker to “speed up” the process) resulted in hard, chewy beans due to the vinegar.

  40. OK. But the real question is how to recover from well cooked, but hard beans. Reading all the stuff on the internet, I added baking soda to my crock pot of hard beans. Exciting! Think of the vinegar and baking soda volcano science experiment. After cleaning up the foam, I continued to let the beans cook over night and was rewarded with soft yummy beans.

    • I’ve tried the baking soda trick, and it does make he beans a bit mushy. And I’ve read the baking soda also diminishes the nutritional value of the beans.

  41. Such an old post but still some replies. Okay Chistopher Kimball and smart readers, how can I get natural bright colored cooked beans? Without anything added,my soaked and cooked black beans become dull purplish grey, my deep burgundy red beans become light maroon. I know my chemistry. When my kids were small, I showed them how the liquid residue from cooking black or “forbidden” rice can be used as a pH indicator. It contains a compound — anthocyanin — the same compound that makes strawberries red but blueberries blue. Add vinegar, it turned red. Add baking soda, it turned blue. So you smarty bean lovers, how do I make my beans look awesome, deep reds and jet black? Is it as simple as adding a base or acid after cooking? I’ll find out in 24 hours.
    By the way, I used to hate beans because of gas but about 6 years ago I learned that the compound at fault was an oligosaccharide, a sugar not digestible by human. But then learned that human mother’s milk also contained oligosaccharides, Why the heck did evolution (or God) waste energy in having the mother produce a sugar not digestible by its infant? Then the answer came to me. I love beans now. I am only 10% human. 90% the cells within me are non-human. I need to take care of the 90% so they could take care of the 10%. We are a symbiotic organism.

  42. I found this blog post because I added a pinch of baking soda to my beans and was thrilled by the improvement in texture and wanted to find out why.

    I am glad to know there is a scientific explanation but sad to know that it may destroy nutrients. I might be willing to make the trade-off because my New Years black-eye peas came out SO wonderful with the pinch of soda.

    My question — How much does that little pinch affect the 2 pounds of beans that I cooked? (I know it had a significant effect on texture but I’m hoping not too much on the nutrients…)

  43. […] There is much debate about whether or not to soak beans before cooking. In all honesty, consuming beans can cause gastric distress in some people. Fortunately, soaking them and increasing consumption over time can help with alleviating this issue. I find that soaking them before cooking is more kind to the bean structure. In fact, the skins tend to stay more intact, which is beneficial if you are using them in a salad. You can read more in-depth about soaking and cooking beans here. […]

  44. It’s been proven that soaking gets rid of a significant amount of the saccharides in the liquid, that cause gas when processed by gut flora, without any other additions, and it also really does shorten the cooking time and make,beans silky smooth and tender skins. If you don’t have time, might I suggest buying a simple pressure cooker, because you can “presoak” with that, in just minutes, drain the liquid, then add fresh water and cook in the pressure cooker or a regular pot (and if you eat meat, I’m vegetarian, it can tenderize cheap cuts of meat). As for eating beans regularly to reduce the gas problem over time: I’ve heard that for years, can’t address that scientifically, but soaking them is what really makes my life easy and gas-free. I just know that my gut is delicate, and soaking overnight with a few water changes is all I need.

    There is also a diet called the “low FODMAP diet” that can help some people, and you can look it up online. It’s not meant to be restrictive permanently, but can help you figure out which foods bother you, they list the foods which have the short-chain saccharide culprits that upset you, with gradual reintroduction of foods that caused problems, including beans.

  45. […] más solubles y que la piel se reblandezca y el interior se cocine antes. Os dejo un link con la explicación más técnica y detallada, por si os interesa (en […]

  46. […] Three (3) Christopher Kimball Blog. America’s Test Kitchen. Cooking Beans 101.    […]

  47. […] how acidic is too acidic? Christopher Kimball and America’s Test Kitchen put this question to the test and found that the pH of bean cooking liquid has to be no lower than 5 in order to achieve a good […]

  48. […] contaminant absorption in their chickpeas and black beans, but tap water is also associated with tougher dried bean skins, which may negatively impact the eating […]

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