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Did you ever think you’d have to search out an article on how to avoid toxicity in kidney beans? Me neither, until I did.
I’m not writing this to be a fear-monger and I’m certainly not writing this to be a self-proclaimed food scientist (I’d fail miserably), but I learned something a little disconcerting about dry red kidney beans earlier this week. Because this wasn’t just news to me, but to many others as well, I decided to write a little tidbit in hopes to spread the word.
In fact, out of everyone I mentioned this to, only one person had been aware of it. ONE.
If you’ve ever worked with dry beans before, you know the drill; rinse, remove any small stones or debris that might have been missed, do a long or short soak, cook and eat. It all seems pretty straightforward, right?
However, there’s a really important grey area (for lack of a better term) — one that I, and many others, had zero knowledge about.
Having only worked with dry lentils before, as far as I knew (and based on the cooking directions I’d read on the packaging which was the same for lentils, black beans and kidney beans alike), all I had to do was an overnight soak and then cook the beans the next day. When reading the word “cook”, I didn’t realize they meant “boil the red kidney beans for X amount of time to rid of *toxins* so you don’t shit your pants and end up in the ER”. (Toxins?) I figured cooking them in the slow cooker with the rest of my chili would be sufficient.
NOPE.
In fact, cooking red kidney beans at a lower temperature, such as 80 degrees C, can increase toxicity in kidney beans five-fold making undercooked kidney beans more dangerous than raw kidney beans.
Awesome.
The only reason I now know all of this is because after three hours of taking in the delicious aroma of my pumpkin chili on Monday, I had to dive in for a taste test; I couldn’t resist. Because the beans were still slightly crispy, I was curious as to how long they would take to become tender and cooked through. I went to Mr. Google, because Google is usually safe for cooking advice (unlike medical advice, yo), and that’s when I learned the awful truth about red kidney beans + Red Kidney Bean Poisoning (Phaseolus vulgaris) or Kinkoti Bean Poisoning.
I could feel the color drain from my face right then and there and my anxiety shot through the roof. I mean, I’d just done a taste test, so I’d be lying if I said that I didn’t nearly crap my pants right there in fear. Instead, I dragged my ass back down to the kitchen and discarded the chili with a huge frown on my face.
What is Red Kidney Bean Poisoning?
Raw kidney beans contain very high amounts of phytohemagglutinin, which makes them much more toxic than other types of beans. As I mentioned earlier, every package of beans I’ve seen has the same basic instructions on the back for quick soaks, overnight soaks, boiling, etc. NONE of them mention the absolute importance of boiling kidney beans at a high temp to kill toxins to dodge poisoning — a poisoning that could result in hospitalization. Even after an overnight soak, which many claim to be unnecessary anymore, kidney beans need to be boiled for at least 10 minutes to kill toxins. (Though, in the Bad Bug Book, the US FDA recommends boiling them for 30 minutes to completely destroy the toxin.)
There is no room for slow cooker action here; if you’re like me, and figured the slow cooker would do the cooking, think again. As I mentioned above, undercooked beans can be more toxic than raw beans.
What happens if you consume raw or undercooked kidney beans?
- Mortality: not reported.
- Toxic dose: As few as four or five raw beans can trigger symptoms.
- Onset: Usually begins with extreme nausea and vomiting within 1 to 3 hours of ingestion of the product, with diarrhea developing later within that timeframe.
- Illness + complications: Upper and lower gastrointestinal illness. Vomiting may become severe.
- Symptoms: In addition to vomiting and diarrhea, abdominal pain has been reported by some people.
So yeah. That’s a thing.
I wanted to write this dojigger so I can reference to it in the future when posting recipes that include red kidney beans and, most importantly, to spread awareness. It’s obviously a little *too* easy to make this mistake.
The good news is I didn’t get sick; the best news is that I made my Pumpkin Chili With Pumpkin Beer again yesterday and it’s basically the best chili ever. (Recipe coming soon!)
I simmered the beans in a crockpot for 5 hours then read this article if I boil beans now will that kill the toxin???
Hi Eleanor,
Sorry for the delay in response. How did things go?
Sooo being a vegan I eat beans A LOT and I avoid all things canned (BPAs), so I need details here! When you say boil for 10-30 minutes, is this the beans being AT a boil for that long? OR a slow simmer maybe? Oh the stress of a simplistic task!
Hey Dylan,
Based on my research, it’s suggested that kidney beans be soaked in water for at least 5 hours,
then drained, and boiled in fresh water for at least 30 minutes. Some people claim they boil them for 10 minutes and it’s sufficient. I think 30 is probably a bit much. I always end up cooking lentils for much less time than the instructions suggest. See how they are after 10 minutes and go from there, I’d say. The point is to cook them through at a high temp to kill the toxin — but you obviously don’t want to end up with a pile of mush, either.
wow. We eat a lot of beans and I have NEVER heard of this. I am definitely sending this to my daughter, who is vegan and soaks her own beans. Just wondering though, could you have dumped your chili into a pressure cooker and saved it?
Hey Bernice, I’m not too familiar with pressure cookers, so I’m not sure. (I’m one of those people who isn’t really comfortable around them, though I’m sure they’ve come a long way, I can’t get past my fears of them blowing up, haha). From what I gather, the beans need to cook quickly and thoroughly at a high heat, which just won’t happen in an oven or slow cooker. I would think that putting the entire chili in a pressure cooker *could* help the beans, but would it turn everything else to mush?
I saw your post when you first learned about this…AND I WAS TERRIFIED TOO. Being someone who likes to save money for recipes, I always buy my beans in large dry bulk bags. I had NO IDEA this was a thing, but thank you so much for spreading the word! (Time to go throw out my freezer meals now, boo.)
Oh no! Such a bummer that you have to pitch food, too. I mean hey, at least we know now, right? I’m glad I wrote this in a timely manner.
Who knew?? I read this earlier in the week and was surprised. Your post is super-informative and will be one we could link to in our own future recipes using kidney beans. Thanks for doing all the hard work for the rest of us :)
I’m glad you found this informative, Elaine! I’m not great with science-speak, but I knew I had to put the info up somewhere. I’d be more than happy to have people use this as a resource when posting bean recipes. Haha, doing the hard work was my pleasure if it means happy bellies and safe chilis :)
Thank you for the info! I didn’t know anything about it. The symptoms sound aweful! Sorry you have to discard the chili, but glad you didn’t find out the hard way!
Thanks, Vicky! I’m really glad I didn’t find out the hard way, either. Haha. My goodness.
Before I started Diversivore, I was complaining to my wife about the fact that this is never pointed out on packaging, or in cookbooks. I’ve even seen cookbooks that include dry, unboiled kidney beans in recipes, and it drives me insane. I wish I’d thought to write it up – but now I’m VERY glad that you did! My condolences to your chili, which was undoubtedly AMAZING (albeit poisonous). Can’t wait to see the final, safe version!
It really blows my mind that this isn’t on packaging. The fact that the cooking instructions are *exactly* the same as the less/non-threatening beans is ridiculous. I mean, put SOMETHING on there for crying out loud. I’m not posting bean recipes without linking back to this from now on.
The good news: the final and safe version was a TOTAL win. Can’t wait for lunch today :)
Oh no! That poor chilli! I’m so glad you caught yourself in time. That’s so scary. And you’re so right, definitely not something people know about. Also, all those ‘make your own infused olive oil’ things on Pinterest? Breeding grounds for botulism. So scary! Thanks for sharing this!
Honestly; I get so upset over food going to waste even if it’s a bit of leftovers, let alone an entire batch of it. I didn’t know that about the infused olive oil! That used to interest me so much, but to hell with that. Some DIY stuff just shouldn’t be DIY, haha.
I just read this even before you posted to Blog Share Friday! I join the ranks of those who did not know this. I only began using beans from scratch this year – so far, mainly chick peas. Makes one feel you dodged a bullet. So many hidden evil things. Family member just recovering from pressed juice food poisoning :-((( Thx Mardi! Diane (FBC-er_
Hey Diane, that’s awful to hear about your family member. I hope they’re feeling better now! You’re right, it seems as though there are so many little evils that we should know more about. I definitely feel like I dodged a bullet, haha. I usually have an iron stomach, but I have a feeling you can’t hide from this one since consuming even as little as five beans can be detrimental :|
Thanks for writing this! I did not know about this, and now that I’m using my slow cooker more, this is very good to know.
I’m glad you found the info useful, Barbara! It’s crazy to me how this sort of thing isn’t well known.