A method for cooking dried beans to increase mineral absorption

As the one in our family who does the grocery shopping and meal prep, I've always taken an interest in nutrition. I read up on foods that are new to me. I loosely track the nutrient content of our meals (I say loosely, because I'm not counting grams or anything that specific. I just pay attention to the key nutrients in the foods that I've planned for us to eat, and try to keep everything in balance.) And I seek out foods to fill what I believe could become nutrient deficits in our diet.

Recently I was researching magnesium, iron and zinc. The information that I learned about these, and other minerals, and their absorption came as something of a surprise. And I have now changed the way I prepare some foods, specifically dried legumes.

We know that dried legumes are an inexpensive source of protein, as well as other nutrients. In our family we have some form of beans several nights of the week. However, many of us are not absorbing the maximum nutrients from beans, due to our soaking process. We are losing out on a good share of calcium, magnesium, iron and zinc.


A better method for soaking your dried beans

For many years, I thought that a quick soak (bring beans and water to a boil, turn off the heat and let sit for 1 hour), was as good as a long overnight soak. In fact, while the long overnight soak is better than a quick soak, there's an even better method for soaking dried legumes.

As it turns out, there's a component in these dried beans called phytic acid. (Phytic acid is also present in whole grains, nuts and seeds.)  Phytic acid binds key minerals, preventing our digestive system from adequately absorbing them. And it inhibits the production of digestive enzymes, resulting in gastrointestinal problems.

There's no need to give up beans, however. Several studies have found that soaking dried beans in very warm water for about 24 hours, reduces the phytic acid levels substantially. The optimum temperature for a soak is 140 degrees F. But for practical purposes, there's a simplified method for this soak, resulting in significantly reduce levels of phytic acid.

• Begin the morning of the day before you plan to cook the beans. 
• Rinse your beans. 
• Bring a kettle of water to a boil. 
• Place beans in a large vessel and pour equal parts boiling water and tap water over the beans, yes, equal parts boiling and room temp water. This will give you roughly 140 degrees F. 
• Put the lid on, and place in the warmest part of your kitchen, without actually heating your pot. If you'll be cooking on the stove or in the oven, place it very close. 
• As the water is absorbed throughout the day, add more. 
• Allow to soak for about 24 hours.
• The next morning, pour off all the soaking water, and rinse well. 

• For cooked, plain beans (to add to bean and rice mixtures, to marinate, or for making refried beans), add new water and begin your cooking process. When all cooked, pour off this water and rinse well again.
• For making a soup, where you want to flavor your beans, after rinsing the soaked beans, begin the cooking process with vegetables, soup bone, seasonings, etc. 

The long soak in warm water will result in beans with significantly-reduced phytic acid levels. Your beans will not only provide you with higher mineral absorption, but will be more digestible as well.

Have a look at these 3 articles for more detailed info on mineral absorption and phytic acid, here, here and here. The first two articles discuss beans in specific, and the preferred method of soaking. The third of these articles gives in depth information on phytates, and grains, nuts and seeds, and how to counteract some of the complications stemming from high phytate content in these foods.

edited 10/13 8:45 AM  reason: to include additional cooking information