Soaking beans

On their face, legumes appear to be rich in minerals. But you are absorbing only about half of the mineral content of your legumes that you deserve to be absorbing. To rebuild from depression, we need our zinc, magnesium, and iron. If beans make up a large part of your diet, there is a real easy way to increase your absorption of these minerals.

Simple change: Soak your legumes overnight in very warm water (140 degrees Fahrenheit) to reduce their phytic acid content.

Big effect: Increase your absorption of minerals in those legumes by 50-100%.

Skeptical? Read on.

Studies have shown that when we reduce phytic acid in food, we absorb more minerals from that food.

Legumes, grains, nuts, and seeds have phytic acid. The phytic acid level varies across these food groups and within the groups. Higher levels of phytic acid is bad from a mineral digestion point of view. Soybeans as a class are very high in phytic acid as are peanuts. The rest of the legume world varies but all have phytic acid and should be prepared properly to give your body more cell-building minerals.

Can I just cook out phytic acid?

Sorry, no.

Phytic acid not cooked out all that effectively. Note in the figure at right that in a 1980 study of phytic acid levels in three cooked beans, kidney beans retained 92% of their phytic acid after cooking, black eyed peas retained 87%, and mung beans retained 64%.

What If I Sprout Beans?

Some people germinate their beans – they soak them and then let them sprout until they form little tails. Sprouting increases the vitamin content and, to some degree, it reduces the phytic acid levels. Note in the figure at right that after five days of sprouting, chick peas maintained about 60% of their phytate content and lentils retained about 50% of their original phytic acid content. Cooking on top of germination will reduce the content further but if your main aim is to eat chili beans rather than bean sprouts, there is an easier and more effective method.

Soak Your Beans

My mom used to soak her beans so that they would cook much more quickly. It saved her cooking time and, unbeknownst to her, it increased her mineral absorption because it reduced the phytic acid content.

In the figure at right I present the phytic acid remaining after 18 hours of soaking. Great northern beans maintained 30% of their original phytic acid content, pinto beans 47% and kidney beans 48%. These results are better than cooking and germination and there should be added phytic acid loss in cooking these soaked legumes. However, we can do even better.

Soak Beans In Very Warm Water

One study soaked California small white beans for three hours at various temperatures. In the figure below I summarize the findings. Temperatures too hot or too cold were not very effective at reducing phytic acid. The most effective soaking temperature was 140º Fahrenheit.

Keep in mind that the temperature study soaked the beans for only three hours. The soaking study soaked them for 18 hours. At 140º Fahrenheit the temperature study reduced in three hours about the same percentage of phytic acid as the soaking study that soaked beans for 18 hours at room temperature.

Both time and temperature matter.

Soak your beans overnight in very warm water in a warm space in your house.

With a small amount of preparation, you will save cooking time and you will give your body more minerals.

My method:
Warm your water in a kettle and combine boiling water with your filtered or tap water. Cover the beans with water and put them in a warm place. I begin to soak my beans in the morning on the day before I plan to cook them. As they absorb water, I add more warm water. I don’t pretend to achieve or maintain 140 º Fahrenheit, but I give the beans plenty of soaking time. You will find that with this method, you will digest the beans better too.

After soaking, I rinse the beans and cook them according to the recipe. They will cook much more quickly than a recipe that starts with beans that are not soaked.

For the purists: pH levels
Purists concerned about the phytic acid level will also add something acid to the water. An acid pH will be more effective at breaking down the phytic acid. However, I don’t recommend this approach because you will sacrifice flavor and texture.

We conducted an experiment with a recent batch of beans. We soaked them both as described above but we added some cultured milk to one to make the soaking solution more acid.

Both batches cooked fairly well, though the acid solution beans were a bit more crunchy. Furthermore, in a blind taste test, both my mom and I picked the regular water beans as the standout in flavor. The herbs and spices used in seasoning permeated the beans much better if they were soaked in plain water. With a long soaking time and in a warm temperature, there is no reason to sacrifice flavor.

More posts like this one:

  1. Why do you have to soak beans for a day?
  2. Soy and Phytic Acid: Stick with Fermented Tempeh and Miso
  3. Soaking Grains For Better Mineral Absorption — Resources

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