If You Don't Know Beans about Beans...

beansHow many different types of beans can you name?  Maybe 8 - 10?  Well, you missed a few. Wikipedia says, "The world's gene banks hold about 40,000 bean varieties, although only a fraction are mass-produced for regular consumption."  Why are the others being ignored? Food process engineer Dr. Timothy Bowser explains that mass-produced beans generally come from a few cultivated varieties that have special qualities which have been proven over the years to work well for growers, processors, and consumers.


What actually classifies a plant as a bean, and what doesn't?  Searching for the answer got us on muddy ground because the category has expanded over the centuries.  The word "bean," which originally referred only to New World plants, now includes some Old World types as well.  We can, at least, say that beans are plants that grow in a pod.  But, of course, not all plants that grow in pods are true beans, for example, cocoa beans and vanilla beans.  Are peas beans? Some say yes. Wikipedia says no; they're "leguminous vegetable crops." According to the Mayo Clinic website, beans and peas are all members of the legume family because they grow in pods. So much for a definition.


Let's move on to more important bean facts: why you should eat them; solutions (or partial ones) to the all-to-common and embarrassing consequence of eating beans; shelf life tips; and some common types of beans. 


Why Are Beans Called A Superfood? 


In the Americas and in Europe, domesticated beans go back to the second millennium B.C.  Today, they're often placed on a short list of superfoods in health newsletters.  Why the high rating?  A recent article in U.S. News Health called beans "one of the most neglected and under-valued items [in the supermarket]."  That's probably true in the U.S., but when we visited Costa Rica and Cuba, we were served beans at least once a day and, some days, with every meal!   And a Mexican dinner almost always comes with a side of beans.


If you're neglecting beans, consider changing your habits.  Here are some reasons to do so:


  •  Beans are an inexpensive and excellent source of low-fat (or no-fat) protein.
  •  They also contain vitamins, minerals (such as iron), carbohydrates, and antioxidants. 
  • They're cholesterol-free and contain little or no fat.
  • They're high in dietary fiber.  Most common ones have about 5-8 grams per 1/2 cup.


How do these characteristics contribute to your health?  The Tufts University Health and Nutrition Letter says they contribute by doing the following:


  •  Reducing the risk of heart disease by lowering bad cholesterol;
  •  Reducing blood pressure; and
  • Improving glycemic control (thus helping diabetics and those at risk of developing diabetes).


Now you're wondering, "How many beans do I need to eat to get these wonderful benefits?"  No need to become a bean-counter.  Current U.S. government recommendations are for 1 - 2 cups per week.  (On the USDA MYPLATE showing the recommended diet, beans count as both protein and vegetables.)  The Tufts Health and Nutrition Letter says many people would do well on 1/2 cup per day.  How can you consume them every day?  Try tossing them into a salad, soup, or casserole.  You may hardly notice they're there.


What About That Embarrassing Bean Problem?


Some people with digestive problems eschew beans altogether.  One of the most common problems is flatulence (gas), which is both uncomfortable and embarrassing.  Good news: there are ways to avoid or at least minimize this problem. Food scientist Dr. Catherine Cutter (and other sources) point out that washing fresh, dried, or canned beans before cooking them will decrease the flatulence.


In case you're wondering what causes the gas, here's the answer:  Beans contain short-chain sugar polymers that cannot be digested in the stomach and get passed on to the intestines.  The newsletter Environmental Nutrition advises consumers to soak raw or canned beans and then toss out the water and use fresh water for cooking them.  Wikipedia says overnight soaking will remove 5-10% of the gas-producing sugars.


Environmental Nutrition adds two other recommendations:  1) add the herb epazote to the cooking liquid.  It's often used in Mexican cooking to degas beans.  2) Try taking Beano® before eating a meal containing beans.  It's an over-the-counter natural enzyme that helps the body to digest those indigestible sugars in beans. 


Yet another suggestion: choose green beans.  Food process engineer Dr. Timothy Bowser points out that gas is "not much of an issue with green beans," which he praises as being the easiest and tastiest type of beans to prepare.


How Are Beans Sold?


Beans can be purchased fresh, frozen, dried, or canned.  (Probably the most common ones purchased fresh are green beans.)  The Tufts University Health and Nutrition Letter says, "Dried beans that you soak and cook take more time [than using canned ones] but taste really good and cost less." When using canned beans, remember to rinse them first to cut down on the sodium content. 


Food scientist Dr. Joe Regenstein points out that most frozen beans have been blanched (given a short heat treatment to stop enzymes that might negatively affect the product) before freezing.


How Long Do Beans Last?


Fresh beans should be refrigerated and kept for only a few days before cooking.  For shelf life information on common refrigerated beans, see our chart on this page: "Peas and Beans."  The same chart also gives freezer shelf life data.


When we asked our site's Advisory Board scientists how long dried beans last, Dr. Regenstein said, "Forever.  Because they hold up so well at room temperature, it makes no sense to freeze them. "


Dr. Bowser also emphasizes the durability of beans: "Uncooked, dried beans can last for years if they are of good initial quality and are kept in a cool, dry, insect-free environment. Frozen, dried beans can last much longer."


Wondering how long you can keep a store-bought can of beans? Dr. Bowser says, "The shelf-life for canned beans is well past the use-by date on the container; however, they may have noticeable losses/changes in flavor and color. Also, vitamin content will reduce over time." For additional information on the shelf life of canned vegetables (which includes canned beans), consult this Shelf Life Advice page: "Canned Vegetables Shelf Life." 


What about the shelf life of refrigerated cooked beans? Dr. Regenstein reminds us that proper handling extends shelf life:  "One cannot come up with a single simple rule for shelf life. If you take the product while it is hot and cover it, i.e., keep it in the pot, you minimize recontamination. Then you probably have a week. The smell, look, and taste can help you determine quality. If your goal is to keep the beans a while, put the container at the bottom back of the fridge, where it's probably coolest."  


The Tufts Health and Nutrition Letter suggests that, when cooking up a batch of dried beans, you make extra and freeze the beans in their cooking liquid. In an airtight container, the beans will last for 2-3 months. Dr. Cutter agrees that beans in a liquid, for example in soup, will freeze fine.  However, Dr. Bowser says, "I'm no fan of bean dishes that have been frozen, but some bean purees function well after freezing and defrosting." 


Keep in mind that the usual recommendation for keeping refrigerated leftovers is about 3 days.  After that, presumably, quality deteriorates.  Should you eat beans that are 5 days old?  If properly stored and if their appearance, smell, and taste pass inspection,  go ahead.  Remember that shelf life advice is about quality, not safety, and good quality is, to some extent, a matter of opinion.


Can Beans Be Dangerous?


Some types of raw beans--particularly red and kidney beans--contain a harmful toxin.  It must be destroyed by boiling for at least 10 minutes.  Wikipedia warns that undercooking may result in beans that are even more toxic than uncooked ones! Furthermore, cooking beans in a slow cooker (because it cooks with lower temperatures) may not destroy the toxins.  However, if the beans are boiled for awhile, they should be safe to eat.


Should you make your own canned beans?  Emphatically, no, says food scientist Dr. Karin Allen.   "Buy commercially canned beans instead of canning your own. The risk of botulism poisoning from home canning is too great.  It is difficult to destroy the spores.  They can wake up and contaminate the beans."


What Are Some Common Types of Beans?


Here is just a brief alphabetical list of some common beans you may want to add to your diet:


Black beans:  In Havana, I kid you not, we were served black beans with rice at every meal! The website Real Simple gives the taste a thumbs up, saying that they have "a velvety texture and a subtly sweet taste."  For more on our experiences with this dish in Cuba, see "What's on the Menu in Cuba?"  We didn't even know those shiny little beans were full of healthful magnesium. 


Chickpeas (garbanzo beans): Real Simple says these "are consumed more than any other bean in the world."    I believe them since this is the bean used to make hummus.


Edamame: (soybeans): If you frequent Asian restaurants--especially Japanese or Korean-- you've probably nibbled on these and eaten them raw, right from the shell.  If you're female and concerned about a connection between eating soy and breast cancer, note this Environmental Nutrition statement: "The American Institute for Cancer Research reports that consuming up to two or three servings per day of soy products is safe, even for breast cancer survivors." 


Kidney beans: These kidney-shaped beans, says the Whole Foods website, are especially good in simmered dishes because they absorb the flavors of seasonings and other foods they're cooked with. 


Lentils: These beans come in three varieties.  The brown ones are sold in most grocery stores, but you may need to go to a specialty store to find the green or red ones. The brown ones are the cheapest. They're usually used for soups.  The green ones stay firm when cooked and are a good choice for salads.  The red ones, which turn golden when cooked, are often used in purees and Indian food.  Unlike other beans, lentils don't need to be presoaked, says the Mayo Clinic website. Try them in soups, stews, salads, or served over rice.  Season with turmeric or ginger.


Lima beans:  There are two types: the larger butter beans and the smaller baby limas.  Real Simple says that, because they have a starchy interior, they can easily become mushy, so the best way to cook them is in quick sautées.  It's easy to find them either canned or frozen.


Pinto beans: These small beans are multi-colored mottled) when raw, hence the "painted pony" nickname.  When cooked, they become "a beautiful pink color," says Whole Foods.  The company advises consumers to look carefully at the product before purchasing to be sure there's no evidence of moisture or insects and no cracks in the beans. 













en.wikipedia.org "Phaseolus vulgaris" (the common bean)



en.wikipedia.org "Bean"



health.usnews.com "Beans:  The Undervalued Superfood"



whfoods.com "Kidney beans"



realsimple.com "Common Types of Beans"



mayoclinic.com "Nutrition and Healthy Eating:  Question: Lentils: How do I cook with them?"



Environmental Nutrition "Edamame: Fresh, Whole, Healthy," March 2013.


Environmental Nutrition "Gas-Free Beans and Green Coffee Bean Extract," February 2013.


Tufts University Health & Nutrition Letter "Legumes Improve Heart Risk, Glycemic Control,"

March 2013.


mayoclinic.com "Nutrition and Healthy Eating:  Question:Lentils: How do I cook with them?




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