You know the song… “Beans, beans, the musical fruit, the more you eat the more you toot!”

But what if I told you there’s a way to make beans more digestible and avoid the bloating and farts?

Beans are a staple in many diets around the world. They’re affordable and nutrient dense.

However, for some, beans can lead to digestive discomfort due to certain compounds they contain. Fortunately, traditional preparation methods can significantly enhance bean digestibility and nutrient absorption.

Why do beans make you fart?

Beans contain oligosaccharides, such as raffinose and stachyose, which are complex sugars that the human digestive system struggles to break down. These sugars pass into the colon undigested, where gut bacteria ferment them, producing gas and leading to bloating or discomfort.

Or, if you want a food scientist to explain it:

“Alpha-galactosides or Raffinose Family Oligosaccharides (RFOs) are enriched in legumes and are considered as anti-nutritional factors responsible for inducing flatulence. Due to a lack of alpha-galactosidases in the stomachs of humans and other monogastric animals, these RFOs are not metabolized and are passed to the intestines to be processed by gut bacteria leading to distressing flatulence.”

And another:

“The raffinose family of oligosaccharides–including stachyose and verbascose–occurs in seeds of food legumes at levels that cause flatulence in man and animals. These carbohydrates escape digestion because there is no α-galactosidase activity in mammalian intestinal mucosa and because they are not absorbed into the blood. Consequently, bacteria in the lower intestinal tract metabolize them to form large amounts of carbon dioxide and hydrogen and to lower the pH. The amount and pattern of expelled gases reflect differences in type, location, and abundance of intestinal microorganisms possessing α-galactosidase activity in a favorable nutrient environment.”

What else makes beans difficult to digest?

Beyond the difficult-to-digest oligosaccharides in beans, they also contain several anti-nutrients: phytic acid, lectins, and oxalates.

Now, I know a lot of people choose to avoid or demonize beans (and a whole host of other foods) because they contain these compounds, but it’s a bit hard to reconcile that you see them consumed all over the world in other cultures.

The difference is that they used specific cooking methods and preparation techniques to reduce the levels of these compounds. And we can do the same!

Before I jump into these techniques, I want to mention a few reasons beans are worth including in your diet, even if it’s just on occasion.

Beans are rich in fiber, which supports digestive health, and combined with their protein content also helps with blood sugar regulation. Beans also provide key micronutrients, including magnesium, potassium, zinc, folate, and other B vitamins, which are essential for energy metabolism, cardiovascular health, and fetal development in pregnancy.

They also contain phytonutrients and antioxidant compounds that may offer protective effects against chronic diseases like heart disease, diabetes, and certain cancers. When properly prepared, beans can be a highly nutrient-dense and versatile addition to the diet, especially if you have a tight food budget.

Sure, the protein quality in beans/legumes is not the same as animal proteins, but they can still contribute to overall protein intake.

Let’s get into the traditional preparation methods that can make beans more digestible and more nutritious.

How to Make Beans More Digestible and Reduce Gas Using Traditional Preparation Methods

1. Soak Beans Overnight

Soaking beans before cooking is a time-honored practice that helps reduce difficult-to-digest and anti-nutritional factors:

Breaks down phytic acid: Phytic acid can bind minerals like iron, zinc, and calcium, reducing their bioavailability. Soaking beans has been shown to decrease phytic acid content, enhancing mineral absorption.
Leaches out oligosaccharides: Soaking helps dissolve some of the indigestible sugars responsible for gas production. Just be sure to drain the soaking water and replace with fresh water (or bone broth) before cooking.
Reduces oxalates and lectins: Soaking beans reduces oxalates by leaching these water-soluble compounds into the soaking water, which is then discarded. It also helps reduce lectins by softening the beans, making heat more effective at fully deactivating these compounds during cooking.

How to soak beans:

Place dried beans in a large bowl (stir them around with your hand to pick out any stray stones, as these sometimes are not completely removed during processing; remember, they grow in the ground!).
Cover the beans with filtered water. Add enough to cover the beans with a few extra inches of water, as they will absorb a lot of it and plump up. (Optionally: add a piece of kombu, see #2)
Let them soak for 8–12 hours or overnight at room temperature.
Drain and rinse the beans thoroughly before cooking.

2. Add Kombu Seaweed

Kombu, a type of edible kelp, is revered in Japanese and Korean cuisines for its flavor and health benefits. In Korea, kombu is called dasima. You can find dried kombu at most Asian markets. When added to beans during the soaking process, kombu:

Introduces Alpha-Galactosidase: This enzyme helps break down oligosaccharides like raffinose, reducing gas production. This is the same enzyme in the product Bean-O!
Enhances Flavor: Kombu imparts a subtle umami taste, enriching the overall flavor profile of the dish.
Adds Nutrients: It’s a source of iodine and other trace minerals.

A quick note on kombu: I used to add the kombu during the cooking step, and while this does still reduce the oligosaccharides to some extent, it’s actually more effective to add kombu to the soaking water. This is because the alpha-galactosidase enzyme is sensitive to heat and becomes deactivated once the beans come to temperature (it starts degrading at 55 °C/131 °F, which is even before the beans come to a boil).

So I’ve experimented with this and found that adding the kombu to the soaking water makes the beans less farty (technical term, of course!).

All you need to do is add a 2–3 inch piece of dried kombu to the beans when you soak them in water. After soaking, drain the water, but retain the kombu and leave it with the beans during cooking (it usually breaks down/disintegrates during cooking, or you can remove it afterwards).

3. Use Bone Broth

Using bone broth instead of water adds depth of flavor and nutritional benefits:

Rich in Collagen/Gelatin: Supports joint and gut health.
Mineral Dense: Provides calcium, magnesium, and phosphorus.
Enhances Digestibility: The gelatin in bone broth may aid in digesting beans more comfortably.

After the beans are soaked and soaking water is drained, use enough bone broth to cover the beans for cooking. That’s it!

4. Slow Cook or Pressure Cook

Slow cooking or pressure cooking beans helps break down tough fibers, oligosaccharides, and lectins.These longer, gentler cooking methods essentially pre-digest the beans for you, making them easier on your gut and improving mineral absorption.

If you’re starting with pre-soaked beans, they usually take less time to cook, however the longer they cook, the softer and more digestible they become. If cooking on the stove top, I’ll let the beans cook on very low heat for a few extra hours after they’re soft. If I’m using the slow cooker, I’ll let the beans cook on low heat for 6-8 hours. If using a pressure cooker (like an Instant Pot), I set to “high pressure” for 45 minutes and let the natural pressure release.

Step-by-Step Guide: Preparing Digestible Beans

Soak the beans with kombu: Place beans in a bowl with enough water to cover the beans by 2-3 inches of water. Add a 2-3 inch piece of kombu seaweed. Let them soak for 8–12 hours or overnight at room temperature. Drain and rinse the beans thoroughly before cooking (retain the kombu for cooking).
Slow cook or pressure cook: In a pot, combine beans with bone broth (or water, if you’re not using bone broth). Sometimes I also add a chopped onion or a can of tomatoes at this stage.

- If cooking on the stovetop, bring to a boil, then reduce heat and simmer, covered until beans are tender.
- If using a slow cooker, cook on low, covered for 6-8 hours.
- If using a pressure cooker, cook on high pressure for 45 minutes.

Season: Don’t add salt until the beans are soft! Herbs and spices can be added earlier, but if you add the salt before cooking, it can make the beans tough.

Cooking Beans in Bulk

When cooking beans from dried, it’s often easiest to prepare a full 16-ounce (1-pound) bag at once. This yields roughly 6–8 cups of cooked beans.

After the beans have fully cooled, portion leftovers into freezer containers (or silicone freezer trays) in 1–2 cup increments. Properly cooked beans freeze very well. Having pre-cooked beans on hand makes it easy to add them to soups, stews, or quick meals without repeating the soaking and long cooking process each time.

So instead of relying on canned beans, I have a small freezer stash to pull from! And it’s a lot cheaper than canned beans.

There is a brand of canned beans that soaks their beans before canning (Eden) and even adds kombu, but they’re obviously more expensive than regular canned beans. And no, I have no relationship with that brand, just mentioning it for those who want a more convenient option.

Summary

As you can see, making beans more digestible isn’t complicated, it just requires a bit of prep.

All you need to do is soak overnight with kombu and slow cook in mineral-rich bone broth!

Why it works:

Soaking and using kombu enhances nutrient absorption by reducing antinutrients like phytic acid.
Bone broth adds gelatin, amino acids, and minerals, improving the overall nutrient profile to nourish the gut.
Cooking them thoroughly, whether low and slow or with the help of a pressure cooker, further helps reduce compounds that can irritate the digestive system, including phytic acid and lectins.

These traditional methods have stood the test of time for a reason: they make beans more nourishing, more digestible, and (in my opinion), more delicious. Enjoy!

If you try this out and find it helps you digest beans easier, tell me about it in the comments!

References

Tuck, C. J., et al. “Increasing symptoms in irritable bowel symptoms with ingestion of galacto-oligosaccharides are mitigated by α-galactosidase treatment.” Official journal of the American College of Gastroenterology| ACG 113.1 (2018): 124-134.
Arunraj, Rex, et al. “Spatial regulation of alpha-galactosidase activity and its influence on raffinose family oligosaccharides during seed maturation and germination in Cicer arietinum.” Plant signaling & behavior 15.8 (2020): 1709707.
Rackis, Joseph J. “Oligosaccharides of food legumes: Alpha-galactosidase activity and the flatus problem.” 1975. 207-222.
Sarkhel, Shubhajit, and Anupam Roy. “Phytic acid and its reduction in pulse matrix: Structure–function relationship owing to bioavailability enhancement of micronutrients.” Journal of Food Process Engineering 45.5 (2022): e14030.
Shi, Lan, Susan D. Arntfield, and Michael Nickerson. “Changes in levels of phytic acid, lectins and oxalates during soaking and cooking of Canadian pulses.” Food Research International 107 (2018): 660-668.
Bakunina I Yu et al. Diversity of glycosidase activities in epiphytic Bacteroidetes from marine algae. Microbiology. 2012;81:688‑695.
Di Stefano, Michele, et al. “The effect of oral α-galactosidase on intestinal gas production and gas-related symptoms.” Digestive Diseases and Sciences 52 (2007): 78-83.
Han, Yoo Ri et al. “Production of α- and β-galactosidases from Bifidobacterium longum subsp. longum RD47.” Journal of Microbiology and Biotechnology vol. 24,5 (2014): 675-82.
Zhang, Yianna Y., et al. “Revisiting phytate-element interactions: implications for iron, zinc and calcium bioavailability, with emphasis on legumes.” Critical reviews in food science and nutrition 62.6 (2022): 1696-1712.