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Hay Box Cooking: Wonderbag and Nissan Thermos

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This is my Wonderbag all sealed up tight to keep nearly all it's heat in. It's just as good an insulator as hay, and much smaller and neater!

This is my Wonderbag all sealed up tight to keep nearly all it’s heat in. It’s just as good an insulator as hay, and much smaller and neater!

In todays post we are going to continue our look at how vandwellers can be preparing for survival in bad times with very little extra effort. We’ve been talking about cooking and now we specifically want to focus on cooking methods that lend themselves very well to vandwelling and survivalists. One thing we want is to burn less fuel because of its hidden costs beyond just the money you pay for it:

  • Time spent in tending and watching your food cooking.
  • Finding room to carry the fuel in your car, van or RV. Adding a thermos to your cooking supplies can cut the amount of fuel you use in half, greatly reducing the amount of fuel you need to carry.
  • The hassle of running out of fuel unexpectedly with a half cooked meal.
  • If you are using wood, you can save time collecting the wood and reduce the problem of keeping wood dry in the rain.
  • In the summer a long period of cooking creates a lot of extra unwanted heat in the van or RV.
  • Burning fuel damages the planet. I know you may think that is a just a wacko environmentalist thing to say but seven billion people collectively burn a huge amount of fuel for cooking and if they all reduced it by a third it would make an immense difference to the environment.

Hay-Box Cooking
There is a method of cooking called “hay-box cooking” that has been used for thousands of years because it solves many of those problems. The idea behind it hasn’t changed over the millennia and it is as simple as these three steps:

  1. Bring your food to a boil (some foods will need to be left on the stove to simmer for a while)
  2. Turn the stove off,
  3. Put the pot into some kind of insulated box to let it continue cooking.

Thousands of years ago they didn’t have the kind of insulations we have today so they used the best thing they had available which was hay. A big pile of hay has a very high insulation value and if you put your pot into the middle of one it would stay steaming hot for a long time. Because they ate a lot of tough meats, roots, tubers, grains and legumes that needed a long period of time simmering they found they could cut their fuel use drastically by allowing the insulating value of the hay to do the simmering instead of burning wood, coal or dung. When you had to walk many miles to find more fuel that became very important!

The Wonderbag opened up. This is not a good pot because the tall lid wastes space, it's too big for Judy and I and the handles stick out to much. We replaced it with the MSR.

The Wonderbag opened up. This is not a good pot because the tall lid wastes space, it’s too big for Judy and I and the handles stick out to much. We replaced it with the MSR.

With our advances in technology we don’t have to rely on hay for our thermal insulation anymore, we’ve developed far more efficient methods. I’m going to review two that I own that work extremely well: a Nissan Thermos and a Wonderbag. I’ll start with the Wonderbag because you may have never heard of it and it is a wonderfully useful invention that I have fallen totally in love with!
This is odern Hay Box cooking at it's best. The Wonderbag is a heavily insulated bag that keeps cooking your food for many hours after you take it off the stove, and it does it in the same pot. This post had been in the Wonderbag for 3 hours and was still at 135 degrees.

This is modern Hay Box cooking at it’s best. The Wonderbag is a heavily insulated bag that keeps cooking your food for many hours after you take it off the stove, and it does it in the same pot. This MSR pot had been in the Wonderbag for 3 hours and was still at 135 degrees. But we are at 7000 feet, so at a lower elevation it would have stayed warmer, longer.

Most cooks have taken a pot off the stove and wrapped it in a towel to keep the food hot until it was ready to serve. The Wonderbag is that idea on steroids! It is a bag designed to keep a pot of food hot for several hours. In effect it turns any  pot into a slow cooker!
I know exactly what your first thought is going to be, “What a bunch of baloney! Nothing can turn a plain old pot into a slow cooker, I can wrap a pot in a towel and it will work just as well.” No, it honestly won’t work as well; this thing is truly amazing and totally lives up to its hype! I have to admit that when I first showed it to Judy that was exactly her reaction, “Just another gimmick you’ve fallen for!” But now that we’ve been using it for a while she has become a believer and loves it as much as I do! See it on Amazon here: Wonderbag Non-Electric Slow Cooker
When you undo the drawstring the bag opens falls away from the pot. Here you can see the "plug" that keeps heat from escaping form the top opening.

When you undo the drawstring the bag opens and falls away from the pot. Here you can see the “plug” that keeps heat from escaping from the top opening.

Essentially it is a bag filled with some kind of super-insulation that has an opening at the top with a draw-string closure. It also has large, insulated “plug” (I don’t know how else to describe it) that sits on top of the pot to keep the heat from going out the opening. Here are step-by-step instructions on how to use it:

  1. Put all the food in a pot and bring it to a full rolling boil.
  2. Some foods take longer than others so you may have to let them continue at a low boil. How long to leave it at a s low boil is going to be a matter of trial and error experimentation (I have a table of suggested times later in the post). We’re starting out by letting it boil for half the recommended time, then putting it in the Wonderbag.
  3. Turn off the stove and put the pot with the lid on it into the Wonderbag, put the plug on top of it, and close the drawstring tight.
  4. Leave it in for as long as necessary.
  5. Open and serve!

We’ve been experimenting with different foods and every one of them has turned out well. For example, she cooked a pot of potatoes and quinoa by bringing it to a rolling boil and then letting it continue at a slow boil for about 8 minutes and then put the pot in the Wonderbag for 3 hours. When we opened it the food was still at 130 degrees and the potatoes were fully cooked the way I like them; soft but not mushy. That cuts the time it normally takes to boil potatoes in half, saving at least 10 minutes of cooking. Here is a chart of typical cooking times for common foods using a Wonderbag (at higher elevations you will need to extend the times):
Here are some tips on using the Wonderbag:

  • The tighter the lid fits, the better it works. Anything that lets the heat out of the pot will tend to cool off the food.
  • The food should fill the pot nearly full. Empty air in the pot doesn’t insulate as well as a pot full of food.
  • Put a folded dish towel under the pot on the bottom of the Wonderbag to make cleaning spills easier.
  • Long handles leaves open spaces which waste heat so try to find a pot with short handles.

We think the Wonderbag works so well it’s worth looking for a pot that works great with it. I bought a MSR (Mountain Safety Research) specifically to work with the Wonderbag because it has a tight fitting lid that actually locks closed. It works wonderfully well in the Wonderbag and is extremely strong and durable. At $25 it’s fairly expensive, but because MSR makes premium backpacking products, it will last for many decades. I think it was money well spent! See it at Amazon here: MSR Stowaway Pot 1.6 L

The handle on the MSR  pot folds over the top and latches so the lid stays on tight keeping the food hot and preventing spils. We found it to be the perfect size for us!

The handle on the MSR pot folds over the top and latches so the lid stays on tight keeping the food hot and preventing spills. 

Here you see the pot open and the handle flipped over. It's a high quality stainless steel and the perfect size for us!

Here you see the pot open and the handle flipped over. It’s a high quality stainless steel and the perfect size for us! Highly recommended for $25!

Nissan Thermos
Probably many of you have heard of, or even tried Thermos cooking. In essence it’s exactly the same thing as hay box cooking with the Wonderbag except you must 1) pre-heat the thermos with boiling water 2) pour the food into the Thermos and 3) wash both the pot and thermos. I own a Nissan Thermos and it works well for thermal cooking, but it isn’t nearly as convenient because it burns more fuel and takes more time pre-heating the thermos. And cleaning them is usually a pain in the butt! For those reasons I greatly prefer the Wonderbag and recommend it instead. Thermos 48-Ounce Wide Mouth Stainless-Steel Bottle

This is what cooking looks like in most of the Third World. Having a tool like the Wonderbag can literally change their lives! Whenever you buy one, they give one away free to a family in Africa!

You may be put off by the price of the Wonderbag which is $50—and I must admit that is a lot of money. But when you buy one, one is donated to a family in Africa and that is something I wanted to support. The woman who owns the company grew up as a child in Africa and she created the Wonderbag to meet a huge need she saw there. Because her heart goes out to the women of Africa, for every one sold in America, the UK and Europe she gives one away to a woman in Africa for free. You may be thinking, “Why would women in Africa want one of those?” Because many of them are so poor they can only afford food that needs very long cooking times and yet they are also too poor to afford to buy fuel for the stove. That means a huge amount of their time goes to cooking and a large part of their tiny budget goes to fuel or they have to spend many hours a day gathering wood. Having something like the Wonderbag frees them (and their female children) from breathing cooking fumes and allows them to do other things than cook all day like go to school or get a job.
I’d encourage you to go to the page on the Wonderbag site to see all the wonderful benefits that come to women in the third world from a Wonderbag: and also

Thanks for shopping Amazon from links on my blog!

I make a few pennies from every purchase you make (even if you buy something else) and it costs you no more.


  1. LaVonne Ellis

    I have been doing improvised haybox cooking with towels and blankets for several years, and I love it. The Wonderbag is definitely on my wishlist!

    • Bob

      We like it a lot so far LaVonne!

  2. Peggy

    I’ve never heard of the Wonderbag before…what a great idea. Simple yet effective by the sounds of it. I totally love the idea of them giving one to a family in Africa for every one that is bought. I have a few friends from Africa and my husband travelled to Guinea, W. Africa a couple of years ago…just yesterday we were talking about how the women have to collect wood in order to turn it into charcoal to cook with. Very labor-intensive and time-consuming. Along those lines, have you heard of the Wello Water Wheel? It’s a device used to collect water, another very time-consuming activity in third world countries. Here’s a short Ted Talks video about them:

    • Bob

      Peggy, giving a free one to a family in Africa is one of the main reasons I bought it. It’s a nice touch in my life but it can literally save the life of a family in Africa. I thought it was a bargain!

  3. breid1903

    we had a home made one as a kid. the selling point was that we didn’t have to watch food all day. we bought cheap and this helped soften our food. this puppy is a lot more user friendly.
    if you boil you water to warm thermos you can then use it in your wonderbag
    peaceup raz

    • Bob

      breid, yes, the two work very well together! And the thermos is smaller so it works really well for one person. My problem with thermos cooking is cleaning an extra item and even with a wide mouth it is harder to clean than a pot. And I like having left-overs. That way I save time and effort by cooking-cleaning once and eating multiple times. But the therms is too small for left-overs.

  4. Ming

    Nice review of the Wonderbag, Bob.
    After experimenting with blankets and styrofoam packing peanuts, I eventually bought this cooker when I found it on sale. I’m very happy with it, and when I cook rice (I don’t cook 4.5l of rice at a time), I use a smaller camping pot like your MSR and swaddle it in towels and pop it in the thermal shell.

    • Bob

      Ming, I’ve heard a lot of good things about those thermal cookers. But it’s expensive and large! I’m glad it’s working well for you! Eventually, it will pay for itself in fuel savings and the time savings is priceless!

      • Ming

        yes, I love the time saving, and not having an electric crockpot plugged in all day while I am not there to supervise. Also, it’s the only no-stir, no-scorch way I’ve found to make congee.
        And I agree, it’s expensive. I put off getting one for years because of that, and then finally decided that I would not know if I liked it unless I got one.

        • Bob

          Ming, not only that, but I think the slow, gentle cooking really does taste better!

  5. Ming

    BTW, what are the dimensions of the pot/Wonderbag combo? I like my cooker for its svelteness and general regular kitchen-appliance look.

  6. Linda Sand

    Can you stick a magnet to an MSR pot? I do my boiling on an induction burner so need my pot bottoms to be magnetic. But the handles of the pots I have now would not fit into a Wonderbag.

    • Bob

      Linda, it’s stainless steel so i assume it will. I’ll give it a try and get back to you.

    • gadgetMe

      Magnet will not work on stainless steel.
      Iron is needed in its composition for a magnet to work

      • Bob

        Thanks for that clarification gadgetme! I didn’t know that.

      • Linda Sand

        But some stainless steel cookware has iron in it. So I still need to know if this pot is one that a magnet will stick to the bottom of. I can’t just wander over to Amazon with my magnet to see so I asked Bob to check his for me. GadgetMe’s clarification didn’t clarify my issue.

        • Bob

          I’ll check it Linda.

      • Grant Robertson

        All stainless steel has iron in it. Steel is iron with carbon mixed in and stainless steel is steel with chromium, and sometimes nickle, mixed in too. The chromium and nickle change the arrangement of the iron molecules such that a magnetic field has less or no effect. Please see the following article for a more technical explanation:

        • Bob

          Thanks Grant.

  7. Gloria Brooks

    It’s taken me almost a year now to figure out a happy-go-lucky, sustainable way to cook. I like convenience and I like cooking to be quick and easy with no fuss whatsoever. I’m no chef. My most favorite method of cooking was plugging in a Roadpro water boiler and small pan into my 15 amp 12-volt socket hooked right up to my house battery system, until it blew two weeks ago . But, using cheapo Roadpro stuff that lasts only a half a year sickens my heart as I throw another item into the landfill. Wish I could find higher end 12-volt cooking stuff!! Anyone know, PLEASE shoot me an email or reply to this comment. Thanks!
    Right now, until I can afford upgrades to my 12-volt system (Bob suggests Anderson Connectors) and purchase a Kelly Kettle for backup, my only option seems to be the 20 lb propane tank with my my 1-burner stove, of which I seem to spend a lot of time staring at blankly, lately, shaking in my shoes. Now, why I’m so scared of it, I don’t know. I guess it’s taking a while for me to warm back up to it. I used it outdoors for two months last summer. I was afraid to turn the thing on outdoors as of today! What a scaredy cat! I haven’t used it in like 8 months. Well, I think I got over the fear of turning it on…at least outdoors. I’m STILL cringing at the idea of cooking in my van with the 20 lb propane tank and my 1-burner coleman stove and I hate the idea of lugging both in and out of the van either everytime I cook or move camp.
    So, with all my putzing around with it (checking and re-checking knobs and connections, making sure nothing’s going to blow up) I’ve still not turned the things on in my rig! But, I’m working up the courage to do it. And of course, I know to have PLENTY of ventilation (windows and vent open) if I do dare cook in the van. But, there’s just something about that big, scary tank that bothers me indoors with the 12-foot hose wrapped around it all snake-like and the the stove on my tiny counter space with the extension joint held up in the air awkwardly. I’ll re-inforce all of the male parts with teflon tape. I read about doing that somewhere. DON’T want any leaks now for this over-zealous safety queen do we!?
    It’s been about two weeks since I’ve cooked a meal. It’s too windy up here on this mountain to even cook outside. I’m not sure if I can get over all the “What if” fears of cooking inside. That 20 lb tank would build muscle lugging in and out, but what a pain in the butt and the mess of leaving it all outside (been there done that) and constantly dusting it all off when moving camp. Whine, whine, whine. I know.
    Though I dislike cooking outside (dealing with wind and dust), I think the Kelly Kettle would solve some of my whoas. I like the idea of it being light-weight (easy in and out of the van) and fuel shouldn’t be a problem to find until I’m camping where I’m not allowed to collect it (which happens fairly often, unfortunately).
    I also like the Wonderbag now, though I’ve been doing pretty well with the thermos cooking. But, first I have to solve my problem of even getting my food to a boil LOL. I never bother with preheating the thermos though. It’s just a walmart thermos and does well once I dump the heated contents into it. I’ve also soaked 3-minute oats in it without cooking for an easy and nice tasting meal. I did that recently and added canned fruit, banana and chocolate chip morsals. YUM! I’m not married to heated food, obviously. At this point, being able to cook at all is a luxury in my life. Thank goodness I can at least eat stuff out of cans, bags and soak my dehydrated foods with no worries. But, admittedly, I’m missing heating my food and making tea!

    • Bob

      Hi Gloria, all the people that I know who are afraid of propane use these butane stoves:
      They are small, light and easy to handle. The fuel can be hard to find but it’s everywhere in Quartzsite, so people stock up while they are there. Asians stores, restaurant supply stores and a big chain in California called Smart and Final sell them. You can buy the bottles off Amazon but I don’t know what the restrictions are on shipping. I think it is the thing that will work for you.
      Another butane stove that might work is the little backpacking stoves like this one: Walmart probably sells one.
      They use fuel bottles like this and you can buy them anywhere, including Walmart.
      They are easily portable and taking it inside and out will be very easy.

      • Gloria Brooks

        Thank, Bob. I’m going to see first if I can get over the 20 lb. propane tank in the van, fear, than I’ll go from there. I’ve heard of the butane option, and realize the fuel is much more expensive. So, my shoe-string budget may win out over my fears.

        • Ming

          Gloria, have you ever tried cooking with denatured alcohol stoves? The $ outlay is very minimal to try it ($2 for fuel, $1 for pot stand), it’s light to carry in and out of the van, and I’ve used it inside the house so I don’t see why you couldn’t use it in the van if you ventilate well.
          Bob, do you know anyone who cooks inside their vehicle with alcohol?
          Alcohol stoves are easy to make: you can even just use the bottom 3/4″ of a pop can, a pot stand from the dollar store, and a tinfoil windshield to get yourself started. Alcohol stove designs are all over the internet.
          Danger wise, you could possibly spill flaming alcohol if you bump an overfull stove, but the odd time I’ve done that, I just put out the flames with a strong lungful of air. It was a lot more hairy trying to put out fireballs from white gas and propane stoves, as I recall.

          • Gloria Brooks

            Interestingly, I’ve been looking at alcohol stoves. My most favored option, if I can find it, will be an RV store with a pre-made Anderson 12-volt socket. Boy, that will be a happy day if I can find it as I’d prefer not to make it if I don’t have to! In the mean time, I think I’m building up courage now to cook my first meal in the van with the 20 pounder tonight! It’s Hormel chili! If I lose heart, I’ll just eat it out of the can.

          • neil mcanally

            I cook on alcohol in the van; I use a homemade stove – look up ‘supercat stove’ on the internet – easiest stove to build….. It’s not too steady so you have to babysit it, but if you’re only boiling for a few minutes, not a big problem. I made mine from a vienna sausage can; took almost as long to eat the sausage as to make the stove! I put the stove in a metal pie pan for safety. Works great, costs about $0! Neil

          • Bob

            Alcohol stoves are great. Thanks for that info, Neil.

          • Bob

            I’ve experiented with them inside the van, but I’ve never cooked a meal inside and I don’t know anyone who does. I don’t think I would use any liquid fuel inside the van.

        • Bob

          Good luck Gloria!

        • rita

          i have been cooking with butane for decades and never had a any big asian store the stove cost less then $20.the butane at these stores cost under $6 for a four-pack,about $30 or less for a box of 24 ,or 28 ?not sure on that.i have seen one cartridge by coleman at walmart for $3.50 though.I cook a lot,usually fast, and find butane not expensive at fuss,no muss,automatic on and off.never having had anything propane i have no way of comparing the two,but just observing the hassle with propane gives me a headache.the only downside with butane is finding it reasonably.migth have to make a trip to a big city. OT Bob,you migth want to know that your advise re.van-dwelling was the major motivating factor for me to live happily in my van full time for almost 3 years now.been all over,met a lot of nice people.Thank you

          • Bob

            Hi Rita, I know a lot of people who use and love butane stoves for all the reasons you mention. I’m glad it’s working so well for you!
            I’m also really glad to have played some role in your finding a new life in vandwelling! You’re always welcome in my camp!

    • breid1903

      master plumber here. i work with gas. get 2 or 3 lp detectors. yes 2 or 3. lp is heavier than air. put them low by where you use gas. some detectors will be set off by ANY petrochemical. as in pipe dope or hair spray. i have customers that have a smoke detector, a carbon monoxide detector and a gas detector in every room of their home. + extras is rooms that they have concerns about.
      i know some body will pop up and tell me that is an over kill. tell it to the people that got their home back. peace of mine and being able to sleep at night, well there is something to said for that. also butane is even heavier than lp. gasoline fumes are heaver than air.
      peaceup raz

      • Linda

        Sleeping with a detector on your bed pillow will give you some peace of mind.

  8. Douglas V

    I always like to look at new ideas, it sometimes gives me even more ideas to work from.

  9. Al Christensen

    I’m not the kind of guy for slow cooking. I don’t think about my next meal hours ahead. I think about it when I’m hungry, and when I’m hungry I want it quickly. That’s the way it was when I lived in a house, so I already have a sufficient repertoire of quick cooking meals. I’ve been using the same 20lb propane tank for eight months now, including for heating. Including for a big old pot of potatoes (that took forever to boil) for Christmas dinner. I use propane very efficiently and sparingly, yet I haven’t turned into a skeleton. Unfortunately.

    • Bob

      Al, those potatoes turned out great too!!
      Different things work best for different people, I’m just glad you found a system that worked for you!

  10. CAE

    Fruits. Veggies and nuts. Eat when you want. Long shelf life without special environments like fridges. Most require no cooking…And very healthy for you.

    • Gloria Brooks

      Yes, I do that too! Variety is the spice of life!

    • Bob

      That’s good advice CAE!

  11. Tim S.

    Hi Bob,
    I just discovered your website a few minutes ago. What a wealth of information.
    I have done some Thermos Cooking making breakfast cereal from whole-wheat berries that cook overnight in a thermos and are then run through a blender and topped with soymilk, yoghurt or whatever. Breakfast then costs about 10 cents.
    Many environmentalists are down on Nuclear Power but if it is permitted there is a world of energy and opportunities.
    Best Wishes,
    Tim S.

    • Bob

      Tim, nuclear power is a truly mixed blessing. When all goes well it is great! When it goes bad, it is truly a horrendous, unspeakable disaster.
      I think it is a far better idea to just junk the whole concepet of civilization and go back to what we know works.

      • Linda

        I couldn’t agree more! However, you’d think that at least America would convert to thorium instead of the present nuclear power. Much safer. But I don’t expect much out of America; it’s gone to the dogs.

        • Bob

          Nuclear power is way outside my realm of knowledge, so I’ll take your word for it!

  12. Linda

    I’m not RVing but I use this system of cooking in my home and it works very well. I made my own box and use comforters and blankets. They work great.
    I noticed that if you buy one of these Wonder Bags, that the company will send one free to Africa. In fact, I’m noticing that many companies do this sort of thing today. I’m looking for a company that will help AMERICANS. If I find that company I will DEFINITELY buy their product.

    • Bob

      That’s a good idea Linda!

  13. Norm

    The standard method for cooking pasta is extremely wasteful, of both water and energy.
    A better way. Cover your pasta with water plus a bit more, bring to boil, stir, and turn off the heat. Cover and wait for the prescribed time (usually 10 min), drain and serve. (No need to insulate the pot).

    • Bob

      Thanks Norm for that tip. I never insulate pasta because it cooks so quick. It’s grains, beans and one-pot meal where thermal cooking makes the big difference. It usually reduces the cook-time by 30-50%.

  14. Dave

    Wonderbag is pricy, so I’m going to try a small duffel bag with the packaging peanuts. Also need to make a hole for my pressure cooker handle.
    I think this method of cooking will also help to prevent burning the food at the bottom of the pan, which is what happens to me occasionally.
    Slow cooking also blends the spices nicely, so lots of benefits to a a well-designed pot cozy.

    • Bob

      Dave, it is very expensive, but remember you are buying two of them and one is being sent to Africa ad given away for free. But I’m sure your’re right, you can make something that will work nearly as well for much less.

    • Bob

      Thanks Donna, that’s very helpful!

  15. eatfrysmith

    I’ve never seen this way of cooking before. But all new things should a try.

  16. NanAnymn

    We have four children, two in diapers. In the present climate my better half just conveys two or three diapers, a few wipes, a join of void baggies and a pacifier directly in her tote. We guard some additional garments in the ass of the minivan. The entirety else is sauce.

  17. NanAnymn

    We have four children, two in diapers. Immediately my better half just conveys two or three diapers, a not many wipes, a couple of emptiness baggies and a pacifier soon in her tote. We guard some additional garments in the raise of the minivan. Everything else is sauce.

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