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Soak Your 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.

In the book I describe the research on phytates and human digestion. Phytates matter. They do decrease our body’s ability to absorb vital minerals. See more on phytic acid in nuts, phytates in whole wheat, and phytic acid in soymilk for other examples.

In this article I will provide additional research on beans and phytates.

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

Can I just cook out phytates?

Sorry, no.

Phytates are not cooked out all that effectively. Note in the figure below that in a 1980 study of phytate levels in three cooked beans, kidney beans retained 92% of their phytates after cooking, black eyed peas retained 87%, and mung beans retained 64%.

What if I sprout them?
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 below 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 them.
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 below I present the phytates 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 phytate loss in cooking these soaked legumes. However, we can do even better.

Soak them 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 phytates. 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 phytates 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 depression-busting 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 to make up for my lack of temperature monitoring. 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 phytates. 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.

Learn more about the Rebuild book.

IMPORTANT DISCLAIMER: Information on this web site is provided for informational purposes only and is not intended as a substitute for the advice provided by your physician or other healthcare professional. Consult with your physician before making any changes to your diet.