How do I stop beans and pulses giving me wind?

The cause is specific: beans contain oligosaccharides — raffinose, stachyose, verbascose — that humans cannot digest, so they arrive intact in the large intestine where bacteria ferment them and produce gas. Everything that helps either removes those sugars before you eat them or changes the bacteria doing the fermenting.

Step by step

1. Soak long, in plenty of water, and discard it.Eight hours or overnight in three or four times the volume of water. A meaningful proportion of the oligosaccharides leaches out into the water. Then pour that water away and cook in fresh — cooking them in the soaking water puts it all back.
2. Change the water once during a long soak.A second change of water part way through removes more. It costs nothing and it is the single most effective preparation step.
3. Rinse tinned pulses thoroughly.The liquid in the tin carries the same sugars. A proper rinse in a sieve under running water until the foaming stops removes a good deal of it, along with excess salt.
4. Cook them fully.Undercooked pulses are harder on the gut and more likely to cause discomfort. Beans should be soft enough to crush against the roof of your mouth without effort.
5. Build up gradually — this is the one that actually works.Gut bacteria adapt to what they are regularly given. People who eat pulses daily produce far less gas from them than people who eat them twice a year. Start with small portions two or three times a week and increase over a few weeks. Eating them less often makes the problem worse, not better.
6. Try the traditional additions, with realistic expectations.Asafoetida, epazote, ajwain, cumin, ginger, fennel and bay are all used in pulse-eating cuisines and many people find they help with the discomfort. The evidence for them removing the oligosaccharides is weak; the evidence that they are carminatives and help with the symptoms is longer-standing than any of us.
7. Choose the easier pulses if you are starting out.Split red lentils, split peas and skinned mung dal are much easier than kidney beans, soya beans and chickpeas, because splitting and skinning removes much of the problem material. Working up through lentils to whole beans is a sensible route.
8. Consider an enzyme supplement if you need one for an occasion.Alpha-galactosidase supplements, sold in pharmacies, supply the enzyme humans lack and are genuinely effective taken with the meal. Useful occasionally; not a substitute for adaptation.

Tips

• Bicarbonate of soda in the soak removes more oligosaccharides than plain water, but it also destroys some B vitamins and can make beans slimy. A pinch, not a spoonful.
• Pressure cooking appears to reduce the effect further than ordinary boiling, probably by breaking down more of the sugars.
• Persistent, severe bloating from ordinary portions of pulses is worth mentioning to a GP rather than working around, particularly if it comes with other digestive symptoms.

Common mistakes

• Cooking beans in their soaking water — Everything you spent the night leaching out goes straight back in. Drain and refill.
• Giving up after one bad experience — The first large portion after months without is always the worst. Adaptation is real and it takes a few weeks.
• Eating a very large portion to 'get used to it' — Overwhelming an unadapted gut is uncomfortable and puts people off for years. Small and frequent beats large and occasional.

Questions people ask