Food Safety Issues/Black beans


QUESTION: I have never cooked black beans, but I would very much like to. I am trying to find trustworthy information about whether or not they have a lectin issue like kidney beans.
I usually soak pinto beans only about four hours - any reason black beans need more?
Any reason to be sure to boil 10-30 minutes like kidney beans (which i have never made) or will simmering after simply bringing to a boil be sufficient?
Thank you for your time!

ANSWER: Hi Karen,

All beans contain lectin, with red kidney beans having the highest concentration.  Because of this, the U.S Food and Drug Administration recommends boiling dry beans for 30 minutes to ensure they reach a sufficient temperature for long enough to completely destroy the lectin. For all dry beans, the FDA also recommends an initial soak of at least 5 hours in water which should then be discarded.

So I would soak all your dried beans for at least 5 hours, drain and discard the water, then replace with fresh water.  Bring the beans to a boil and boil 30 minutes, which is long enough to destroy the lectin but not fully cook the beans.  Lower the heat and simmer the beans until the beans are sufficiently softened.

If you follow the above guidelines for all your beans, lectin should not be an issue.


---------- FOLLOW-UP ----------

QUESTION: Should I assume that cooking beans in my pressure cooker is like boiling them?

ANSWER: Hi Again,

Yes, it is fine to use a pressure cooker for cooking beans as long as you follow the manufacturer's directions.

Presto, one of the makers of pressure cookers, has specific instructions for how to use the pressure cooker for cooking dried beans.  I suggest you check out this document:  on page 29 for specific instructions for using a pressure cooker for cooking beans.


---------- FOLLOW-UP ----------

QUESTION: I hate to ask still another question, but after looking through the pressure cooker manual, I noticed that the cooking times for beans are very short -  3 minutes, 6 minutes - the newer pressure cookers must reach higher temperatures than my old model. Do you think the lectins are destroyed faster the higher the temperature above boiling?

Hi Karen,

The temperature inside a pressure cooker at 15 psi is 250 degrees F which is 32 degrees above boiling.  At this temperature foods cook quicker and lectins would be destroyed at a much faster rate.

I feel confident that cooking beans in a pressure cooker is safe and provides the needed temperatures to both cook and destroy any lectins present.

If you have additional questions, please feel free to ask them.


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Carol Schlitt


I can answer questions on home food safety, sanitation and home food preservation.


I am a former Extension educator, nutrition, wellness and food safety, having retired August 1, 2010. I am a food safety instructor for the Illinois Department of Public Health, a ServSafe Instructor/Proctor and have my own company, Safe & Savory Solutions, Inc -

National Extension Association of Family and Consumer Sciences (Past President and current Historian), St. Louis Culinary Society.

BS - University of Illinois MS - Southern Illinois University at Edwardsville

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