How to Cook Food in a Thermos

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by the author of The Interactive Prepper’s Book of Lists and The Prepper’s Workbook

Looking for a way to cook food off-grid but don’t have a fireplace or indoor method to do so? I have fantastic news. That thermos you have stashed away is good for far more than keeping your coffee hot in a cold house or making homemade yogurt (seriously – yogurt!) If you have a way to boil water and a thermos, you can make all sorts of food.

This is a method made popular by boaters because it uses far less fuel than cooking on a stovetop and reduces the potential for a fire on board. But, it’s the perfect method for land-loving preppers, too. If you have limited fuel or lack an elaborate off-grid cooking set-up, the humble thermos just might be your new best friend. And in these times of outrageous energy bills, having a cooking method that relies on less power is always a good idea.

Here’s everything you need to know about how to cook food in a thermos.

What kind of thermos should you use for cooking?

You can’t just pick up a cheap knock-off in the back-to-school aisle and expect to make meals in it. Those are fine for keeping a meal warm until time to eat, but they cannot handle the boiling water necessary for cooking, nor do they hold enough heat.

While I’m not generally a brand-name shopper, there’s a reason that the Thermos brand has become the ubiquitous name for vacuum bottles. The quality is very high, and you need that kind of excellence for a cooking method on which you plan to depend.

Look for a bottle made from stainless steel. No plastic liners, no glass liners – just steel. I prefer a wide-mouth bottle because it’s way easier to fill and clean, but if you are getting a big bottle, you’ll have to go with a narrow mouth. I use my canning funnel for filling it and a long skinny spatula for getting my food out. A long bottle brush will make clean-up far easier. All of these accessories have many different uses and are widely employed in my kitchen.

This is the thermos I have the best luck with for cooking: the Thermos King 40-ounce jar. For making small amounts of food for just me, this 24-0unce one works well, and it’s what I keep in my bug-out bag. For cooking more food, there is also a 68-ounce thermos.

When the author of tested different vacuum bottles, the Stanley brand did not hold heat nearly as well as the Thermos brand.

Thermos cooking basics

Okay – you have your thermos, and you have your food. How do you get cooking?

First things first, you need to preheat your thermos. Use your first bit of boiling water to pour into it and warm up the insides. Add the water, put the top on, and wait for five minutes. While you’re waiting, bring more water to a boil and do any required pre-cooking of your food. (See the instructions below for details.)

Next, pour out that water and reserve it for different use.

I like to use my canning funnel to fill the thermos. It really cuts down on spills and reduces the risk of burns from the boiling water. Add your food and your boiling water, and quickly put the lid on.

If you are someplace very cold, you may need to add more boiling water partway through your cooking time. Dump your contents out into a bowl, drain it, then put it back in the thermos with more boiling water.

Do NOT take the lid off to check on things. You’ll let out the heat that is cooking your food!

That’s all there is to it! Next, we’ll get into specifics.

How to cook rice in a thermos

Rice is one of the easiest things to cook in a thermos. There are three different kinds of rice you might be cooking. Here are the instructions for each. I always, always, always wash rice before cooking it. If you have the extra water, you should too. You can use the water you’re preheating the thermos with to do so. Discard any water you’ve used to wash rice or use it for sanitation.

Instant Rice: Preheat your thermos, then put equal parts of instant rice and boiling water in. Be sure to leave about an inch at the top of the thermos for the rice to expand. Pop the lid on, and you have rice in 30 minutes! You don’t have to use it right away. Your rice will stay warm for up to 8 hours in the thermos.

White Rice: Preheat your thermos and rinse your rice. On your stove, bring 1 cup of rice and 1.5 cups of water to a boil and simmer for 5 minutes. Empty the water from your thermos, then refill it with your simmering rice and water. Put the lid on and let it sit for 2 hours. If you plan to leave it for longer than 4 hours, reduce the amount of water by a quarter cup so it doesn’t overcook.

Brown Rice: Preheat your thermos and rinse your rice. On your stove, bring 1 cup of rice and 1.5 cups of water to a boil and simmer for 5 minutes. Empty the water from your thermos, then refill it with your simmering rice and water. Put the lid on and let it sit for 4-5 hours.

(Want to know what to eat first in a power outage? Check out our free QUICKSTART Guide.)

How to make soup in a thermos

Here are two different soups you can make easily.

Chicken Noodle Soup

  • Preheat your thermos.
  • Bring 2 cups of chicken broth to a boil on the stovetop.
  • Place 1 cup of dry noodles, 1 tbsp minced onion, 1 tsp garlic powder, and 1 tsp of parsley in your thermos.
  • Pour the boiling broth into your thermos, then put the lid on.
  • Let your thermos sit for about 4 hours.

Split Pea Soup

  • Preheat your thermos for at least 5 minutes.
  • Meanwhile, on the stovetop, place 1 cup of dried, rinsed split peas into a pot, along with diced ham (fresh or freeze-dried), 2 tbsp minced onion, 1 diced carrot (or 1/4 cup freeze-dried carrot), 2 bay leaves, 1/2 tsp sage, 1/2 tsp thyme, salt, and pepper.
  • Bring the mixture to a boil for 3 minutes, then pour it into the thermos.
  • Put the lid on and let it sit for 4-10 hours.

How to make oatmeal in a thermos

Try this easy breakfast even when the power is on!

  • Preheat your thermos.
  • Add 1/2 a cup of rolled oats, 1/2 cup of dried fruit, 1 tsp of cinnamon, 1 tbsp of brown sugar, and a teeny dash of salt to the thermos.
  • Bring 1 cup of your favorite milk (or water) to a boil, then pour it into the thermos.
  • Put the lid on and let it sit for 30 minutes to an hour. Stir in any extra liquid and enjoy.

How to prepare freeze-dried emergency food in a thermos

Here’s a great way to prepare those freeze-dried meals from your buckets while using minimal energy and fuel.

  • Preheat your thermos.
  • Check the directions on your package of freeze-dried food to see how much water to add and bring that amount to a boil.
  • Add the contents of your food package to the thermos, then pour the boiling water in. Be sure to leave room for the food to expand as it’s reconstituted.
  • Put the lid on and let it sit for about an hour and then enjoy your hot meal.

How to cook potatoes in a thermos

Got potatoes but no way to cook them? Try this!

  • Preheat your thermos.
  • Cut your potatoes into chunks, then add them to water in a pot on the stove.
  • Bring your potatoes and water to a boil for 5 minutes, then pour the whole thing into the thermos.
  • Put the lid on and let it sit for 2-3 hours.
  • At serving time, you can drain off the liquid or incorporate it to make mashed potatoes. I like to season my potatoes with freeze-dried butter powder, salt, pepper, and parsley.

How to soak and cook dried beans in a thermos

If you’ve got dried beans but are loathe to use your precious fuel to cook them for hours, try the thermos method, which takes 15 minutes of actual cooking time.

  • First, preheat the thermos.
  • Sort and rinse your beans, then add them to water on the stove. Bring this to a boil for 5 minutes, then pour the beans and water into your thermos.
  • Allow this to sit for two hours. Now your beans are pre-soaked.
  • Change the water and bring your beans and new water to a boil for ten more minutes.
  • Pour this back into your thermos and allow it to sit for three more hours. Make sure you’ve left room for expansion. Your beans should be tender and ready to be seasoned.

Additional thermos cooking resources

The best place I’ve found for advice on this subject is the website You can also find recipes on the official Thermos website.

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Practice, practice, practice.

Thermos cooking is an art form. The first few attempts may not be successful right and may require further cooking or tweaking. As with any preparedness skill, it’s essential to practice and get through the trial and error phase before you really need to use your gear during an emergency.

Have you ever tried to cook food in a thermos? How did it go? Do you have any tips? Are there foods besides those listed here that work well in a thermos? Let’s talk about it in the comments.

About Daisy

Daisy Luther is a coffee-swigging, adventure-seeking, globe-trotting blogger. She is the founder and publisher of three websites.  1) The Organic Prepper, which is about current events, preparedness, self-reliance, and the pursuit of liberty; 2)  The Frugalite, a website with thrifty tips and solutions to help people get a handle on their personal finances without feeling deprived; and 3), an aggregate site where you can find links to all the most important news for those who wish to be prepared. Her work is widely republished across alternative media and she has appeared in many interviews.

Daisy is the best-selling author of 5 traditionally published books, 12 self-published books, and runs a small digital publishing company with PDF guides, printables, and courses at SelfRelianceand You can find her on FacebookPinterest, Gab, MeWe, Parler, Instagram, and Twitter.

Picture of Daisy Luther

Daisy Luther

Daisy Luther is a coffee-swigging, globe-trotting blogger. She is the founder and publisher of three websites.  1) The Organic Prepper, which is about current events, preparedness, self-reliance, and the pursuit of liberty on her website, 2)  The Frugalite, a website with thrifty tips and solutions to help people get a handle on their personal finances without feeling deprived, and 3), an aggregate site where you can find links to all the most important news for those who wish to be prepared. She is widely republished across alternative media and  Daisy is the best-selling author of 5 traditionally published books and runs a small digital publishing company with PDF guides, printables, and courses. You can find her on FacebookPinterest, Gab, MeWe, Parler, Instagram, and Twitter.

Leave a Reply

  • First and foremost, thank you for all of your work and efforts to educate the willing population… I do need to ask though… if we can boil water to heat the thermos and do all the necessary prep , why not just continue cooking? I use a thermos all the time; prep, cook and eat later.

    • It saves tremendously on fuel and allows you to “cook” while on the move or engaged in other activities. 🙂 The fuel needed to boil something for 5 minutes vs. 3 hours is a huge difference.

      • I think I have read about this once or twice before.
        I think of it as kinda like crock pot cooking, but for when the grid is down.
        I can cook on the wood stove, has a purpose built “cook” top. But I like the idea of not having to babysit it (like crock pot cooking) while I do other things.
        Have to look into 2 or 4.

      • There is nothing in the recipes above that requires any ingredient to be boiled for 3 hours, your counterpoint is due to a flawed analysis of the facts, or a willful determination not to consider to them. Why not simply admit Catherine makes a valid point that you failed to take into account. This article was a complete waste of time and your nonsensical defense of it puts you in a position of being not serious, at best.

  • While I highly value the 40 oz Thermos brand thermos bottle I have, there are lots of competitors on the market. This article discusses many of them:

    Best Thermos Flasks and Insulated Bottles in 2022

    There is also a global market for thermal cooking pots that are ideal for doing cooking for larger numbers of people. Amazon is full of them. Even eBay sometimes has deals on some of them.

    A search on Amazon for “thermal cooking pot” produced these many results:

    Obviously such pots don’t work for backpacking but can work well when traveling by vehicle.

    Not only is thermal cooking a great way to stretch/conserve your use of stored fuels … it can also take advantage of sunlight even on days when there might be only a few minutes of usable sunlight if you have something like a parabolic solar reflector or a large Fresnel lens (scavenged from a discarded rear projection TV) to heat up your water.


  • I gifted myself this last year (when I went to check the link, I noticed it has more than doubled in price since I purchased it!!!) Basically a budget version of a Saratoga Jack. You bring food to a full rolling boil for 10 minutes, then put it in the two thermos pots, then close it up, and it continues to cook. Particularly good for lengthy road trips, just bring a soup or stew to a boil, seal up, and leave in the trunk to cook all day for a hot hearty meal in your hotel room.

  • What a great idea for the daily go-bag! I always carry stuff in the car when taking a hike and I hope it would suffice me to get home incase of EMP, riot, etc. So here I have all of this dandy food preps-including kibble and freeze dried chicken bites-in the bag but hadn’t thought of how to heat my goods! ???? Also a great idea for traveling. How many times have I stopped at the hotel/motel and thought, “I just want to eat & sleep!” No take out, no ordering, and certainly no dressing for a restaurant. Don’t forget your coffee or tea; a warm cup goes a long way.

  • The concept of thermal cooking while traveling has another aspect to it. Years ago my 1998 edition of “Manifold Destiny” was a classic about cooking entire meals over the heat from one’s car engine. Written by two experienced rally drivers it’s full of recipes for hitting the road with an empty stomach and a full tank of gas.

    Now suppose that via thermal cooking you only needed enough heat for the first few minutes. That leaves you the option to fire up the engine for that very short time — instead of using your trunk-stored Coleman propane burner that’s dependent on the little green Walmart propane bottles you refilled (in violation of the federal prohibition that carries a stiff fine and prison sentence for transporting those bottles — because you didn’t get the higher priced Flame King bottles which ARE legally OK to transport after refilling).

    Whether or not you choose to to try out thermal cooking via your vehicle engine heat … the “Manifold Destiny” book is a great read. The edition below is the latest that’s available on Amazon but is way older than the 6 month past publication rule that lets you apply for a free inter-library loan to see whether or not to buy the book.

    Manifold Destiny: The One! The Only! Guide to Cooking on Your Car Engine! Paperback – November 18, 2008, by Chris Maynard


    • Cool thermos app. I love “Manifold Destiny”, used to have a copy before passing on to my traveller daughter awhile back. Question: if you cook a chicken in your engine compartment, does your car smell like fried chicken? And if you’ve converted your diesel car to run on fry oil, can you cook onion rings on the side? The possibilities…

    • Old GI trick, learned from a Marine Gunnery Sergent: Use a .50 caliber steel ammo box to hold your food (in those days it was the canned C rations). Use coat hanger wire to strap it down in the engine compartment of your vehicle. After a few hours, your food will be hot. This will obviously work with commercially available canned goods too.

  • I got myself a 16 oz wide mouth thermos and cooked rice in it. In the morning, take a half cup of rice (I like short grain sticky rice), put it in a pan with 1 3/4 cup of water, bring it to a rollicking boil, immediately pop it in the thermos. Then go to work. When I came home, I had hot rice ready to eat. It was never burned. That amount of rice is good for 3–4 meals for me. Others may want more.

    I tried that method to cook pinto beans, but it didn’t work. The beans were only partially cooked. I wonder if it would work to grind the beans first into a flour, then pour in boiling water which should give sort of a bean paste? Or would a bean flour cook so quickly that it would be done before it got into the thermos?

    The other recipes look interesting, I’m tempted to try them out.

    Thanks for the article.

    • Two thoughts:

      1) Did you soak your beans in boiling water first?
      2) You might also want to try a smaller quantity of beans to get them to cook

      I had to experiment a little before I got it to work with beans. 🙂

      • Thanks Daisy:

        The only recipe that I had for beans was bring to a boil, then simmer for hours until soft. That didn’t work with a thermos. I’ll have to do more experiments to get it to work. The pre-soak idea sounds promising.

        Thanks for the reply.

  • Hi Daisy
    This is a great article and with very practical advice.. I love cooking in my thermos– have been doing it for some time now–I especially like putting in different kinds of grains like wheat berries, rice, buckwheat, and groats in the thermos with boiling water– let them cook all night in the thermos, then have a hearty breakfast with maple syrup and butter mixed in. I have cooked soup in mine, but haven’t tried the beans yet. I eat a lot of beans and rice, so thinking about getting another thermos, so I could cook them simultaneously. If I could get a couple more thermoses, I should be able to prepare a whole meal in advance. Another trick my mother shared with me was to grind rice–especially brown long grain rice—in the blender–it will cook in a very few minutes once the water gets boiling–it has the texture of cream of wheat, and is delicious for breakfast with some fruit and maple syrup added. We make instant oatmeal the same way, and just started grinding up the grains, which cuts down on cooking time tremendously—I’m fixing to cook some old fashioned oats in the thermos tonight to have with canned peaches for breakfast in the morning
    Thanks for another great article and food for thought.

  • I have to expand on this. I highly recommend the Thermos Cook and Carry. (or thermos shuttle chef if you can get your hands on one) The cook and carry used to be about $100 in 2019.. now they are scarce and costing more.

    I have used many thermal cookers for the past few years. I use about weekly year round. There is the outer thermos pot and a regular pot that fits inside. You use the regular pot on the stove/fire etc and then after a boil put the whole pot in the thermos pot. Look it up – they are amazing.

    I use this too cook steel cut oats at night and wake up to hot breakfast.
    I use these to cook soup and keep it hot all day.
    I use this to do all my cooking in the summer in the morning and not have to stand in heat during the hot part of the day.
    I use this for fall/winter picnics to bring hot food.
    I use this for summer picnics to bring ice cream. 😀
    I use this to cook food at home while road tripping to bring my own hot food.
    I use this for thanksgiving to keep potatoes, stuffing, and other things perfectly hot until time to serve.
    I use this to keep supper hot when I don’t know when my husband will be coming home from work.
    I have used one as a hot sink to just keep water hot for washing hands..
    Sincerely they are useful.

    Basics methods are to boil for 2 minutes anything like rice, pasta, vegetables then put in the thermal pot and it continues to cook beautifully for 30 minutes around boiling temperatures, then maintains steamy very hot for about 8 hours.

    Basic method for meat is that it MUST be fully thawed! then boil for 10 minutes and put in the thermal pot. Will crock pot slow cook all day to tender amazing-ness.

    It is popular in Japan where energy costs are so high people use them daily as cost reduction on their energy costs. With energy costs rising here – that may soon pay itself off. I have ‘paid off’ mine in savings on eating out by bringing hot foods.

    caveat – Kidney beans need to be boiled longer than 2 minutes due to an enzyme that must be broken down. Not an issue with other beans.
    Caveat- pasta can be tricky- if left all day it gets mushy-
    Anything that can be cooked in a crockpot can be cooked in a thermal pot

    Other brands: Tiger, Nissan and more. They are common in Japan, and therefore somewhat common on Ebay. Look for non-electric rice cooker. Or Thermal cooker (the saratoga jack is not double wall steel, but foam based I believe. I haven’t used that brand, but reviewers state it worked great until it stopped alltogether) I have gotten all of mine used on ebay/mercari etc and always found steel ones.

  • My older edition of “Country Beans” introduced me to the concept of grinding up dried beans into flour (I use the hand cranking option on a Country Living grain mill — usable even during a long term power outage). Some of the Amazon reviews on their later “Country Beans” edition also mention the wonderful discovery on how to cook with bean flour. It’s incredible how much bean flour speeds up the cooking process. This is the latest version that is available on Amazon — it should also be a good candidate for a free interlibrary loan:

    Country Beans – How to cook dry beans in only 3 minutes! Paperback – December 1, 2011, by Rita Bingham

    Some notes on the mill I use — the factory supplied cranking arm in my opinion was too short, so I hand made a longer replacement oak arm with a 14 inch cranking radius from the mill’s pivot center to the hand cranking grip’s center. Then I installed the optional bean augur [note that label] to grind not only dried beans into flour but also to do the same with virtually any kind or combination of grains. I can even grind nuts (or combinations thereof) into nut butter as long as I don’t mind cleaning up the gooey mess afterwards.

    Another advantage of being able to turn what you store into the amount of flour you need immediately is storage life. Fresh flour does not last very long at room temperature — unlike the whole beans or grains — unless the nutritional goodies containing moisture have been removed industrially before your purchase. So the DIY approach to milling only as much as you immediately need gives you 1) a nutritional advantage, and 2) lets the remainder of your produce store in good condition for as many years as you might want.

    There are a number of other kitchen mills on the market. I just acquired mine in the Y2K era without knowing about any competitors.


  • Thank you so much, Daisy! Our thermos has been extricated from cupboard and we’re going to try some of these ideas. Pea soup can take almost a week (OK, slight exaggeration) to cook, so I’m keen to see if the thermos will save the day.

  • The thermos has worked for me in the past. I’ve wrapped the thermos with a towel when driving during the winter to help retain heat. Perhaps I’ll ask the wife to knit a cozy for the thermos for additional heat retention.

  • in defense of the Stanley brand of ‘thermos bottles” >>> nearly indestructible – can take more than “licking and keep a ticking” – it’s the #1 coffee carrier on the industrial job sites for this reason …..

    another reason is the availability of parts – the metal base of the Stanleys are stamped with the model numbers of the parts used – no guessing on what screw cap or cup is required >>> and they still stock the cork for the oldest of the oldest models …..

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