[Gas passing is normal] Americans report passing gas an average of 14 times a day, with the normal range extending up to a frequency of 22 times daily. Many people who think they have too much gas fall well within the normal range, concludes famed flatologist Michael Levitt, M.D., “and they simply have to be informed of their ‘normality.'”

[Sources of flatulence] Flatulence come from two places: swallowed air, and fermentation in the bowel. Things that can cause you to swallow extra air include gum chewing, ill-fitting dentures, sucking on hard candies, drinking through a straw, eating too fast, talking while you eat, and cigarette smoking. So if the fear of lung cancer doesn’t get you to quit smoking, maybe fear of flatulence will.

[Gas due to beans] The main source of gas, though, is the normal bacterial fermentation in our colon of undigested sugars. Dairy products are a leading cause of excessive flatulence, due to poor digestion of the milk sugar lactose, though even people who are lactose tolerant may suffer from dairy.

… they started people on pinto beans, black-eyed peas, or vegetarian baked (navy) beans. During the first week, 35% reported increased flatulence but that fell to 15% by week three, 5% by week five, and 3% by week eight. Much of the bad rap for beans grew out of short-term studies in the 60’s that didn’t account for our body’s ability to adapt.

The indigestible sugars in beans that make it down to our colon may even function as prebiotics to feed our good bacteria and make for a healthier colon.

[Ideas for reducing gas from beans] Even if at first they make us gassy, beans are so health-promoting that we should experiment with ways to keep them in our diet at all costs.

• Lentils, split peas and canned beans tend to be less gas-producing.
• Tofu usually isn’t an offender.
• Repeated soakings of dried beans and tossing the cooking water may help if you boil your own.
• Worse comes to worst, there are cheap supplements that contain alpha-galactosidase, an enzyme shown to break up the bean sugars and take the sail out of your wind.

To reiterate, though, intestinal gas is normal and healthy.

[Question] "I recently heard that the reason humans produce gas after eating beans is because they contain raffinose which is a starch that is poorly digested due to a lack of the enzyme galactosidase. The MD claimed that adding baking soda to the soaking liquid reduced the raffinose. Have you heard anything about this?"

[Answer] Yes indeed, research dating back more than 25 years found that adding baking soda to the soak water of dried beans before cooking (about 1/16 teaspoon per quart) significantly decreases the content of the raffinose family of sugars. — Dr Greger

[Sprouting] One reliable way to "de-gas" legumes is to sprout them first. Cover beans with water for 12 hours, drain off water, lay damp paper towels on the bottom of a baking dish, spread out beans on the moist towels in a single layer, and then let them sprout for the next 12 hours. When you notice tiny white shoots (1/16") beginning to appear they are ready to cook. The tiny plant is utilizing the indigestible sugars for growth.[15] Needless to say, beans will take less time to cook after sprouting.

[Soaking] Researchers in India looked at five different types of beans, soaked in: (a) Plain water for six hours, (b) Plain water for 12 hours, (c) Water with baking soda (1/16 teaspoon per quart) for six hours, (d) Water with baking soda for 12 hours. Afterward, they measured the levels of gas-producing substances left in the beans. They found the fewest in beans soaked for 12 hours. Whether they were soaked in plain water or water with baking soda didn't matter.