Since I wrote about my new favorite kitchen appliance, the Instant Pot pressure cooker, I’ve gotten a lot of comments and questions about if pressure cooking is a healthy way to cook food or if it destroys nutrients.
It is certainly a logical and valid question… in fact it was the question that kept me from trying a pressure cooker for years until I finally decided to research it, and what I found was fascinating.
Growing up, I considered a pressure cooker an antiquated kitchen tool that elderly relatives used and that was most useful for canning. Some pressure cookers can double as a canner, which is probably why my elderly relatives used their pressure cooker more than those in my generation, but it turns out I had missed out on a lot of important points in my quick judgement!
How Does a Pressure Cooker Work?
A pressure cooker is a pressurized (of course) pot that cooks food using a combination of heat and steam. While it would seem that high heat is required, the steam and pressure actually provide much of the cooking power. A pressure cooker has a valve that seals in the steam, creating a high-pressure environment. This is beneficial because it increases the boiling point of the water or liquid in the pot and forces moisture into the food in the form of steam. Both of these help the food cook much more quickly.
How does this work?
Consider this- water boils at a lower temperature at higher altitudes. This is because the lack of pressure allows the water to boil at a lower temperature. You may have noticed special high-altitude cooking instructions on certain recipes and this is partially why. The lower the temperature at which water boils, the faster foods start to dry out and the more difficult it can be to cook. This is also why it takes longer to cook food at higher altitude.
Pressure cooking essentially does the opposite of altitude, it increases the boiling point of water and decreases the cooking time. Since steam can’t escape from the pressure cooker, you avoid water-loss and are able to cook foods without losing heat.
One big advantage of a pressure cooker is that it can cook foods much more quickly and energy efficiently than other methods like stove top, the oven, or even a slow-cooker.
Does Pressure Cooking Use Really High Heat?
This is where some of the confusion starts to come in. Many people assume that since pressure cooking cuts down the cook time so dramatically, it must use a much higher heat. This isn’t the case at all.
As described above, the shortened cooking time is a product of the increased pressure, not increased temperature at all. When researching, the highest recorded boiling point of water in a pressure cooker I could find was 250 degrees. That is still lower than the temperature that most foods are prepared at in the oven or stove top and about the same as a slow-cooker.
In other words, a pressure cooker may cook foods at a lower temperature than most other cooking methods, utilizing the pressure to improve cooking time and efficiency.
Does a Pressure Cooker Destroy Nutrients?
I completely understand this question, as I had the same one. At first glance, the idea of cooking foods more quickly seems too good to be true and it just seems logical that there is a downside, such as a loss of nutrients.
Fortunately, in researching this question, I found that the reverse is actually true!
Readers have asked if a pressure cooker uses high heat (see above) and if this creates the similar negative effects of high-heat methods like grilling and broiling. Again, it makes sense until we delve into the science of heat and pressure and understand that the increased pressure is what creates the faster cooking environment, not higher heat.
To reiterate, pressure cookers actually cook at a lower temperature than most other methods (steaming, roasting, etc.) but do it more efficiently. All cooking methods reduce nutrients to some degree, but I was surprised how much of a difference the cooking method could make!
In fact, a 1995 study found that pressure cooking preserved nutrients in food more than other cooking methods. Another study measured levels of Vitamin C and B-Vitamins in food and found these levels of vitamin retention (the amount remaining in food after cooking):
- Boiling reduced nutrients the most with a range of 40-75% retained (up to a 60% loss of nutrients!)
- Roasting and steaming preserved up to 90% of nutrients (but in some measurements, almost half of nutrients were lost!)
- Pressure cooking did the best job at preserving nutrients with a 90-95% retention rate
This makes sense when you think about it. Since pressure cooking doesn’t require a much higher temperature and shortens the cooking time, there is less time for nutrient loss. For this reason, pressure cooking may actually preserve nutrients better than other methods of cooking.
There are a couple of notable exceptions to this rule:
Pressure cooking does seem to deactivate certain properties in food like phytic acid. I explained in this post about traditional preparation methods for grains how reducing phytic acid and lectins makes the nutrients in foods like grains and beans more absorbable and less likely to irritate the digestive system. Pressure cooking seems to do a better job of deactivating these substances than other cooking methods.
An Important Caveat
There have been conflicting studies that showed that higher levels of nutrients were lost with pressure cooking, but follow up research revealed that most of the nutrients were actually just transferred to the cooking liquid.
For this reason, I make a conscious effort to use only as much cooking liquid as is needed when using a pressure cooker and to re-use the liquid in the meal by making a gravy, drinkable broth or sauce of some kind.
What Can You Cook?
I’ve personally only experimented with roasts, broth, meats, soups, stews, vegetables and rice in the pressure cooker (this is the one I use), but there are instructions and recipes for cooking virtually everything in a pressure cooker (including cheesecake and hard-boiled eggs!).
Many people love the ability to cook rice or beans in under an hour in a pressure cooker but I love that I can prepare a roast in under an hour!
Pressure Cooking: Bottom Line
Like any method of cooking, pressure cooking does destroy some of the nutrients in food, but it actually preserves more than any other cooking method.
With newer electric pressure cookers (like the Instant Pot), pressure cooking is a convenient and healthy way to get food on the table for your family more quickly and easily while still preserving the nutrients in your food.
Do you use a pressure cooker? What is your favorite way to use it?
Nourishing Traditions says NOT to pressure cook. Would love Sally Fallon to weigh in the discussions of PCs n InstantPots.
I am curious about that as well.. I wonder if in light of the more recent research, she would have a different opinion now that when she wrote NT
I have Presto pressure cooker/canners but haven’t used them for pressure cooking because they are made out of aluminum. Does anyone know if/how much of the metal is transferred to the food? Would love to speed up the process for bone broth and bean/grain preparation without having to buy something else if I can help it.
The comments here make me wish (as a new Instant Pot owner) that I had everyone’s recipes!
I am very glad you did this research. Now I feel comfortable buying a pressure cooker, as I’ve been considering canning of bone broths, legumes, stews, etc, delish homemade foods for when we’re not up to cooking. Thanks so much.
Katie you are AWESOME, THANK YOU
Why does the pressure cooker deactivate phytic acid in grains? I would think the longer you cook them changing the water the better…
It seems to be a result of the pressure, but I’m researching this for another post and will hopefully be able to share it soon…
Hi Katie, just wondering if you have had a chance to look into the research on this? Does it apply to legumes as well? I’d love to look into it myself, but I have no idea where to start! Thanks for all you do 🙂
It does deactivate the phytic acid at a higher rate than just cooking slowly. Here is one study that explains why: https://link.springer.com/article/10.1007%2FBF01088088
Also, from Food Renegade:
“PRESSURE COOKING MAKES GRAINS AND LEGUMES MORE DIGESTIBLE BY REDUCING PHYTIC ACID AND LECTINS.
Yep, you read that right. The great enemies found in grains, seeds, and legumes are reduced far more by pressure cooking than by boiling.
In this study done on peas, the phytic acid content of peas soaked overnight and then boiled was only reduced by 29%. But in peas that had been soaked overnight and pressure cooked, the phytic acid was reduced by 54%!
Phytic acid binds minerals and other important nutrients in our digestive tract, keeping us from using them. By reducing the phytic acid content of grains and legumes, we increase their nutrient-availability and render them more digestible.
Pressure cooking is also on par with fermentation as the best way to reduce the lectins (yet another anti-nutrient) in grains.
Turns out, pressure cooking may be the best possible way to cook your soaked beans and grains!”
Thank you, that is a great help!
One more quick question: if pressure cooking preserves nutrients, does slow cooking destroy nutrients?
Thanks for a wonderful, well researched and beautifully articulated post on the wonders of the pressure cooker! I swear by mine for quick cooking of potatoes and beets (with just the right amount of water so as to preserve nutrients), lentils and beans (with overnight soaking as someone mentioned above) and curries (which get a lovely, rich gravy in the PC versus regular pot). The phytic acid point is great too. Having grown up in India, I’ve been intrigued by the recent commentary on anti-nutrients in lentils and legumes making them a poor choice for optimal health. Indians live on lentils and legumes but almost always prepare them in a pressure cooker after soaking, gaining all the wonderful health benefits without too high a dose of anti-nutrients. My cooker even has an old school whistle which my toddler is not a fan of LOL.
My mom uses her antiquated pressure cooker to make her homemade spaghetti sauce. She tosses in all the ingredients, and then walks away. It’s delicious!
I have just started using my InstaPot and love it. I have a stainless steel one. I toss in my quinoa or rice with the recommended amount of water, throw a few handfuls of spinach, other greens, carrot chunks or other goodies on top, then add either already cooked meat,(usually chicken or beef), some spice and olive oil, butter or coconut oil and hit the rice button!
My kids love it when I take a frozen pack of bacon, pressure cook it for about 10 minutes, drain the fat, add the quinoa and water and veggies. I just need to start using bacon that doesnt have sulfites and processing chemicals.
I just bought a liquid smoke that hopefully will give the bacon flavor my kids love, to other dishes!
I cant wait to make prune plum preserves this summer with just the prune plums and raw dates!!!
Does anyone ? the Instant pot’s lid, it’s not magnetic. I question if it’s stainless steel? I did have conformation from the company that the pressure gauge is aluminum(the cage on the inside top of of the lid)…
We just want to be safe 😉
Ruth, because of the nickel component in stainless steel, it is not magnetic. Your fridge magnets won’t ‘stick’ to your stainless steel fridge.
But I remember Dr. Mercola saying that’s a bad thing and quality stainless will have less nickel and be magnetic. Is that why Ruth mentioned that?
Great for bone broth and soups. I live at 6,000 feet. A friend makes 12-24 hour bone broth the “traditional” way, simmering in a non-pressurized pot. I use a stove top 1 gallon Presto. The heat is more easily controlled than with an electric, and the “pressure regulator” (the rocker) is more immediately responsive. We both like to make bison bone broth and compare. The main difference is that mine takes less than half the time, and comes out richer. I let the cooker simmer for 1 1/2 hours, then remove from heat and put it in the sink and run cold water over the top till the safety valve drops, add more water as needed, then put it back on the stove, bring it back up to “rocking” temp, and go another 90 minutes. This saves cool down time. DON’T TRY THIS WITH AN ELECTRIC PRESSURE COOKER, KIDS!!!
Another trick I’ve now begun using: After a few hours (two or three iterations) of pressurized cooking, take the pot off the stove, do a quick-cool down, take out the bones (knock out any partially dissolved marrow into the broth). Put the bones in a denim bag (an old cut-off jeans pant leg will do). Secure one end with large Staples brand binder clips. Holding the open end closed, use a heavy rubber mallet to crack up the bones into smaller pieces (I do this on a cinder block or paver, outside). When you finally decide your broth is done, you will know for certain that you’ve leached out nearly all the bone minerals you can get from your expensive soup bones.
Thanks so much for this post, and your time and effort behind it. It was immensely helpful to me, as I’ve had the same questions.
I have 1 remaining question, I read that the pressure adulterates proteins, did you come across any information on this issue in your research?
(I was curious about the AGA you mentioned, which I had never heard of, and went on a research tangent. Very interesting.)
I saw this claim as well, and could never find any source that showed that it did or didn’t adulterate proteins… or even find where this idea originally came from. Something I’m still researching…
Thanks so much for your response, I so appreciate it and your continued commitment to researching the issue. I saw that a couple people said that Sally Fallen wrote against pressure cooker use in Nourishing Traditions. I got my copy out and looked it up, I found that also, in 2 places, but despite all the other research noted in the book, this issue wasn’t backed up by any.
Its on the WAPF website too, I believe. And adulterating proteins is a concern along with loss of nutrients under pressure. I didnt delve into it, just said, oh…no pressure cookery for us. Now I wish I had. Instantpot that does yogurt, its a slowcooker n even a steamer too?? Toooo cool. Alas, pressure cooking’s not good tho 🙁
Maybe I’ll write WAPF and get a more indepth explanation.
Its gotta be better that nuking the food. Right??
It might well be better than ‘nuking’, who knows? If you find out more from WAPF, please do let us know.
Please tell me this means we’ll see lots of nutrient – rich Instant Pot recipes now, especially for the Real Plans app. ? We’ve tried a lot we love, but I’m always on the lookout for healthy IP meals. Thanks for this info!
Someone commented on the electric pressure cooker taking up more space than a non-electric one, but I found that I was able to get rid of my slow cooker, rice cooker, steamer and yoghurt maker, and it has saved me a TON of space … (Just thought I should mention this in case anyone else has those extra appliances.) My pressure cooker is an Instant Pot.
Exactly. I kept one very small crockpot and got rid of two other crockpots and a rice cooker.
I usually make chicken stock. I add a little vinegar and pressure cook for a total of 6 to 9 hours over 2 or 3 days. This way I can’t pick out the meat and some of the bones are so brittle they can be easily eaten. Does cooking this long destroy nutrients? I just like to add more calcium to my stock and it turns out like jelly every time. Plus it makes my $25 organic chicken go a long way.
No form of cooking will destroy basic nutrients (i.e. calcium, phosphorous, potassium, etc.) simply because those are elements and cannot be broken down by physical means. They simply remain in the solution (for example, bone broth) or can evaporate or “move” into another solution (think osmosis, steam escaping, etc).
I’ve owned several pressure cookers over the past 10-15 years, and my favorite by far is the Kuhn-Rikon. They are a bit pricy, but it is a really good quality pot, and the simple design makes it easy to monitor and regulate the temperature. It also requires less liquid than many models, just 1/4 cup for quick steaming veggies. It doesn’t have a lot of locks and levers, just twist the lid on, and there is a valve at the top to indicate pressure level, 1 line for low, 2 for high. The lid locks automatically if there is pressure in the pot and you can quick release by pressing down on the pressure indicator. I say this because I read a review in a cooking magazine once that was criticized this model in favor of the less expensive Fagor for lack of a safety lock and quick release button. I also have a larger model by Fagor, which is a very good pot for the price, but I find it clunky in comparison to the Kuhn-Rikon, and the pressure indicator can be deceptive. It pops up when there is pressure in the pot, not when it is at the proper cooking pressure. The first few times I used it the recipes came out under cooked, now I wait until I can hear steam escaping to start the cooking time.
My first model was an electric one, like the insta pot, which is easier when you’re first starting out, but you can’t use cold water pressure release with those, and the pan in the one I had was Teflon and not very sturdy. It also takes up a lot of extra space. The stove top models are basically just a really sturdy stainless steel pot with a fancy lid. I use it whenever I have need of a large pot pressure or not. Another tip if you are thinking of purchasing is to go big. You can only fill the pot 1/2 – 3/4 full depending on what you are cooking, but there is no minimum. You can also cook tiered meals in separate bowls at once, such as cooking a pot of rice on top of a roast or stew.
I bought an Instant Pot as a Christmas present to myself:) My favorite is to saute onions, celery, carrots and meat in lard (from pastured pigs), add homemade bone broth and a bit of Red Boat Fish Sauce and cook for 30 -45 minutes. Yum!
My Fagor pressure cooker is my most used pot, used basically every day in addition to the microwave. It’s the only way I make pot roast.
I actually have three PC’s right now. I have an InstantPot, a Cuisinart, and a Cooks that I picked up at a second hand store tor 12 bux which was never used :). I use them 4 to six times a week. I am albsulutely in love with PC cooking and so is my family. The meats are the most tender and the cooking times are fantastically reduced so you leave a tad less carbon footprint. I’ve done entire holiday meals out of one PC.This is the best way to cook almost anything and there is a wealth of recipes on the Internet. My favorite is the Instantpot with the Cuisinart a close second but even the Cook’s does a great job. It is smaller so I usually save it for lighter meals.
I love my pressure cooker. I eat a lot of green beans and cauliflower. My pressure cooker steams these up in about 3 minutes then I saute them on the stove in some seasonings to add flavor. Quick, easy and delicious. I make soups and stews as well.