Cooking Rice In A Thermos To Save 80 Percent Fuel!

Did you know you can cook rice in a thermos? Thermos cooking can potentially save up to 80% of fuel that you might have otherwise used.

Here’s how-to do it, and a recommendation for a good thermos to do it.

Rice is one of those ‘staple foods’ in nearly everyone’s kitchen pantry.

Many preparedness-minded people with a food storage pantry will have (among other things) a quantity of dry foods including rice. An issue with cooking rice though, is that it requires a substantial amount of fuel (heat) energy to cook (boil-simmer) to soften the grains such that you can actually eat it.

If you’re in a situation where you’re trying to conserve your fuel, then the thermos cooking method (such as with rice) will save LOTS of fuel by eliminating the relatively long time needed on a stove burner, etc..

The good news is that I’ve found a way to cook rice with just a fraction of the fuel energy needed compared to conventional cooking methods of boiling and simmering…

Cooking Rice In A Thermos | How-to

I recently tried this, and it worked very well.

1. Heat a quantity of water to boiling.

2. Add the boiling water to a high quality insulated thermos.

3. Add rice.

4. Close thermos and wait several hours.

The only fuel energy consumed is that which is required to get your small pot of water to boil. That’s it. Then shut off the heat!


The thermos I chose to use will hold 6 cups of water. When I first tried the experiment, I only added 1 cup of boiling water to 1/4-cup of rice. I discovered that there was not enough heat energy in the one cup of water to do the job (the rice was partially cooked after many hours, however still too crunchy).

Next, I nearly filled the thermos with boiling water and added a fresh 1/4-cup of rice. After 5 hours passed (I had forgotten about it), I checked and discovered the rice was very well cooked (too much in fact)!

While I have yet to determine the perfect formula (which will vary depending on how much rice you’re trying to cook), the proof of concept is intact. It works!
(Updates below)

Note: You will need to plan ahead (many hours ahead) with your rice.

Double Walled Vacuum Insulated Thermos

For this method to work successfully, it is VERY important that you use a well designed thermos with a double-walled vacuum seal – which will hold the heat for a longer period of time. A cheap plastic thermos will not work, or one that is not under a vacuum.

After researching a bit, I chose a thermos for cooking. It has a fairly wide mouth (easier for food) and will hold enough boiling water (48-ounces) to provide a reservoir of long lasting heat. The thermos (insulation) design has stainless steel walls separated by airless space (under a vacuum).

Since that purchase there is now an even better Thermos (in my opinion). It has a wider mouth for easier access. If I were to do it over again, I would get this one:

From the manufacturer, “As with all Thermos vessels, this container uses vacuum insulation technology for maximum temperature retention that is ideal for soups and other hot foods.”

Stainless King 47 Ounce Vacuum Insulated Food Jar
(view on amzn)

“I conducted a simple performance test myself by priming the unit with boiling water, refilling 5 minutes later (boiling water) at 212F, then storing overnight in a 38F refrigerator. At the end of 10 hours, the water was still quite hot, measuring 155F with a calibrated thermometer!”

said ‘robert’ while reviewing this particular Thermos

Also, the following is an alternative thermal cooker. It’s larger, if that’s what you’re looking for:
1.5L Capacity

All it takes to cook my rice now is a few minutes of fuel to get my water boiling – and that’s it…

As I try more quantities of rice and check the process for time required, I will come back to this post and update with results (e.g. how much for 1 cup of rice until cooked well enough, etc.)

The thermos cooked rice must have smelled so good that my mini Dachshund came out of nowhere and almost got it while I was holding the bowl of rice for the picture (above)

UPDATE: It had been awhile since I used this method to cook rice, but just did it again…

I first filled the thermos with water (to know exactly how much I needed to boil). I then dumped the water into a pot to boil.

Next I then added one cup of (brown rice this time) into the thermos.

After the water came to a boil (about 5 minutes) I dumped it into the thermos over the rice. The thermos took ‘almost’ all the water.

After securing the lid and 8 hours later (I prepared the rice at 10:30AM and had dinner at 6:30PM) I was happy to see that the rice had cooked very well and expanded to fill the thermos perfectly.

I dumped out the rice and strained the remaining water.

The rice was mushy and next time I will try to remember and do a 6 hour slow-cook.

Here are some pictures:


UPDATE: New article about a bigger thermal cooker, Thermal Slow Cooker by Thermos

[ Read: Rice and Beans – A Survival Combination ]


  1. “A hay box, straw box, fireless cooker, insulation cooker, wonder oven or retained-heat cooker is a cooker that utilizes the heat of the food being cooked to complete the cooking process. Food items to be cooked are heated to boiling point, and then insulated. Over a period of time, the food items cook by the heat captured in the insulated container. Generally, it takes three times the normal cooking time to cook food in a hay box” -wikipedia.

    I’ve done this using the crock from my crockpot, with beans, bring the pot of beans to a boil, dump into the crock, put the crock in a cardboard box (or ice chest) that is insulated with towels or blankets, close the top and cover with another blanket, in several hours the beans are done.

  2. I have a thermos for this as well. I also have great pots and pans..well, the lids are the great part.

    After my water reaches boiling point, I just turn the lid/seal it to allow captured heat and the pasta, macaroni, and rice cooks without a burner.

    Don’t forget when water is precious in hard times–use Ziploc bags to cook items in when possible…water saved for another use.

  3. good info/good to know/good to remember.

    I suspect it will be useful in many situations/many food types.

    myself, happened to have a heavily insulated oven. I like to put food – beef or beans/sauce/veg/potatoes in heavy pot with lid in oven. turn it on high for half to one hour and then turn off.

    basically a slow cooker type thing, works well.

  4. I have thought about this problem. That is why I stocked up on instant rice (including some instant brown rice), instant potatoes, and “instant” beans. The beans still require 20 minutes of cooking.

    I also have lots of things that don’t require any cooking such as crackers, cookies, canned fruit, dried fruit, cans of tuna, etc.

  5. You can also do this with hard red wheat, wheatena, oatmeal, and cream of wheat. I dont remember where I learned this trick, but it was over ten years ago. It does work.

  6. My wife noticed that our crockpot cooked a lot faster outside in the sun. The curved glass lid seemed to trap solar energy. Recently stripped out a projection TV for the Fresnel lens. I’ve basically got a 52″ magnifying glass. That’s got to be useful for something like cooking or soldering…

    1. not positive, but am thinking magnifying glass might end with a meltdown or fire????

    2. be careful with what you do with that. go to u tube and you can download videos where people are basically making a laser from them. They can be very dangerous.

  7. Generally when cooking rice you add twice the amount of water as rice used. Would that not be the same here?

    1. Karen, No that didn’t work in this case because there’s not enough heat energy in that small amount of water relative to the amount of rice – to keep it ‘cooking’ in the thermos.

      So instead, I simply added more boiling water than normal, which maintained adequate heat to cook the rice. I then strained the mixture after the rice was cooked well enough (several hours later). In a survival situation I would also save the water.

      1. I tried this method with black rice after soaking it overnight.
        Nothing much happened except the rice lost it’s crunch. Still looks as raw as the original rice after several hours in boiling water and wrapped in towels inside two insulated bags.
        Very surprised to see your image of cooked rice.

        1. I am not familiar with “black rice”. However I have used this method for both white and brown rice without issue, as described.

        2. By black rice, do you mean wild rice? It’s the only rice-like thing I know is black, but always ready to learn about something new.

        3. Black Rice is exactly what it sounds like.. put in search bar that name and buy on line. A, and several other places sell it and there are pictures.I came across this in something this last week.. I was stymied too!

    2. Use a specilised rice cooker.
      The amount of water should only be around 8mm or one quarter of an inch above the rice.
      There are different sized rice cookers depending on the amount of rice required or size of the family.
      Rice cookers produce perfect rice.
      Use Asian rice – Thai or Javan. Western rice has often been modified by western companies only interested in increasing the output per acre and is often full of starch.
      Too cook fried rice – Asian rice is better – less starch. Cook the rice in a rice cooker (or boil it if you don’t have one) let it cool overnight and then fry it next day.

  8. A trick I learned from Mom was to preheat the thermos by putting some boiling water in it, shake, pour it out and then add the measured boiling water and rice.

  9. if you were to store “instant” rice (that stuff which is ready in five minutes)
    all it requires is rice/double amount boiling water/wait five minutes…
    however, I realize most store the “regular” rice, and that “regular” rice stores longer.

    was wondering then, how about if one soaked “regular” rice in water overnight, and then brought the water/rice mix to a boil, and poured straight into the thermos?

    1. Pre-soaking the rice for a few hours (or overnight) will also reduce the cook time by half.

      Also presoak pasta for an hour or so and you can cook it in 1 minute!

      I am also concerned about conserving cooking fuel in a SHTF situation and have tried to research this. Rice does cook well in a solar oven too (if the sun is out). Doesn’t take that long on a hot day, maybe an hour or 2 max.

  10. well, I tried it.

    Last night I put two cups water/one cup of rice in a normal pot, with lid and left it to soak overnight.

    this morning I brought it all to a boil, let it boil for about one minute. Then I shut it off, and left it sit where it was, with lid on.

    After about five to ten minutes (lost track of time, around that), went back and checked, seemed pretty good.

    I would say, this works. Try soaking your rice water overnight. Same might work when cooking grains?

      1. Phil O

        I used white Rice. If you try it with brown, let us know how it does.

  11. Thanks for the tip. For family picnics we cook cooler corn. Put two, three, or four dozen ears of corn in an insulated cooler. Fill with hot/boiling water and close lid. One hour later and you are eating cooked corn on the cob. Works the same as what you did with the rice.

    1. thanks for corn info.

      I thnk the rice would’ve been even better/hotter if it had been done in a thermos, as Ken first experimented.

      1. that is, I meant, soaked over night/bring to boil, then all dumped in thermos.

  12. The trick to thermos cooking is to use the right size thermos. Airspace in the thermos costs BTUs. Optimally the water line should be 1″ below internal lid level. Beans can be soaked overnight and cooked the same way. Boaters and the RV set go one step further and use cookware built for this such as Saratoga Jacks thermal cookers. But bare bones, easy travel solution is a good double wall stainless steel thermos.

  13. Hi, whilst soldiering for a living, we used to fill up our plastic water bottle (1x quart/1x litre)with 1/3 rice 2/3 water in the morning. That evening we would cook it with very little time/fuel involved.

    Now I pre-heat a stainless steel thermos then use the same ratio of rice to boiling water. Adding a little rice oil or olive oil seems to help. 1-2 hours and ready to eat. Yummy..

  14. This fast way to oook works with regular cookware. I use it for noodles, rice, and macaroni at least twice a week.

    Heat to boiling your water. Add item you’re cooking. Turn off the heat;
    add a tight-fitting lid. In a few minutes the heat from the water will cook your rice, macaroni, or noodles.
    No need for an Aladdin although I have one for when the SHTF to conserve my gas, etc.

  15. I first learned of thermos cooking through an online buddy nicknamed BcTruck on Youtube.

    He’s done a few videos on thermos cooking — he uses a large Nisson thermos. I’ve seen him successfully cook rice, beans, and beef stew, plus a few other things.

    He builds and experiments with a variety of wood gassifier heaters and I think his videos would interest most people here. Here’s one using a Silverfire Scout cooker and his Nisson thermos:

    1. He would make a bad beta tester because he would ‘eat anything’ (almost…) ;)

  16. Not only rice but dried beans or peas and so on would do a wonderful job. We really enjoy the news that you share. We also have interesting topics at .

    thanks for being there

  17. Boiling water in a pre-heated glass jar and placed in the sun with a foil reflector. No problem.

  18. Great Post. Just wanted to mention to wash, wash, wash, any rice before cooking. Because of all the chemicals and pesticides, it has been said that rice carries high levels of Arsenic and other contaminants. Look up on the web to verify this. These findings were published late last year.

    1. John, mostly by accident, I have ended up reading a fair bit on arsenic in Rice…

      I believe, regarding arsenic, washing will not help. From what I recall, the arsenic is IN the Rice. Not on surface. Apparently Rice is a particularly excellent soil detoxifier (have read similar about sunflowers), and sucks up (into plant/seed) any toxins in the soil.

  19. I don’t know if this has been proposed before, but what about water seal pots. They have a lip around the edge and when the water is boiling you spin the lid to create the seal). This is how i cook rice at home and in the wild.
    1 cup of rice to 2 cups of water. bring to boil, spin lid (to create the water seal), take off the heat. The atmospheric pressure of the cooling water in the pot will sick the lid down tight, retaining heat. This cooks your rice in about 15 mins. You could put your pot in the freezer and it will still give you perfect rice in 15 mins (true, i have tried it) If you have something to go with your rice (hopefully) you can cook it while the rice is being done away from your one cooking heat source.

    This method has worked for me for 30 years. Just got to find a good water seal pot.
    Cheers, and have a great day.

  20. Actually, that’s a lot of work. Place 1 cup of rice in a pan, add 2 cups of boiling water. Fit lid and bring to simmer. Switch off and leave lid on. Wait 15 minutes. Rice is cooked, in a pan and using far less power than it takes to heat so many cups of water.

    Water seal lid is not required as long as the lid is a good fit.

    Must be fun cleaning out a Thermos.

  21. Ken,
    I know I’m commenting on an old post here…
    I plan to do all my cooking like this in a SHTF scenario. The smell of a wood fire carries, the smell of cooking food can carry just as far. If there are starving people around they are going to be smelling that food, even if it is just noodles/rice. Cooking this way, the only thing they smell is a fire. If you are using a man made fuel, hopefully they won’t even smell the fire…

    1. Yes, situational awareness during a time of SHTF (e.g. smell of cooking foods) will be paramount to one’s security.

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