Food Storage, Not Just For Storing: WONDER BOX COOKER . . . Just In Time For Summer!

Food Storage, Not Just For Storing: WONDER BOX COOKER . . . Just In Time For Summer!.

Wednesday, May 13, 2009

WONDER BOX COOKER . . . Just In Time For Summer!

For the step by step pictures click HERE .

I was just talking to my sister-in-law and she told me about this little wonder. Have you heard about them? They would be great in an emergency, but how about now with the summer weather hitting with a vengeance?!? It would be a great propane saver too if you do a lot of cooking out side or while camping. Check it out!

Wonder Boxes work like vacuum flasks. In these days when we are being warned of worldwide shortages of food and fuel, this wonder box and it’s simplicity is designed to keep food at the temperature needed for cooking. Using very little fuel you only use about 15 minutes of energy to bring the food to the required temperature and then put it into the Wonder box. It makes it as though it were a thermos. On the flip side it will also keep ice-cream cold for about 4 hours.

Brief Cooking Instructions:

Boil your food on the stove for 10 – 15 minutes until the food is heated right through. (In practice this is too long.)

Use any cooking pot, provided it does not have a long handle, but do not use a large pot for a small amount of food. The W’box does not work well if there is a large air space. Remember that the more food or liquid that you have in the pot, the longer and better it will cook.

Put the lid on the pot before you remove the pot from the stove so the lid can also get hot. Make sure the nest in the bottom cushion is ready to take the pot and that it is nearby so you do not lose heat carrying the pot around. Place pot into the nest of the W’box, making sure that the sides are snug against the pot, so there are no air pockets. Quickly cover the pot with the top cushion, making sure there are no gaps or air pockets. Make sure that no one peeks inside. If this happens, heat will escape, and the food will not cook properly.

Do not leave the W’box on a metal surface while it is being used. Metal is a good conductor of heat and may draw off some heat through the bottom.

When cooking anything like a roast or a whole chicken, the liquid around it can boil before the meat has reached the same temperature. Make sure the liquid covers the meat and it has come to a boil. Meat must be covered with liquid! The cooking time seems to be 3-4 hours, or all day. It is sure to never burn.

Note: We had a chicken that was put in at 9:30 in the morning before church. This single dad prepared the chicken by placing it into an oven-cooking bag. He added spices to the chicken closed the bag completely (no added moisture was added to the bag) then brought the pot of water with the chicken in, to a boil and put it all in to the W’box. We ate with him at 4:00pm and as he tried to carve the chicken that was well cooked; the steam was ‘rolling’ off the chicken. It was still so hot he worked with forks to carve it. Nb: the opening to the bag was left protruding from under the lid.

The W’box was designed for cooking meals, but it can also be used for keeping food hot, cold or frozen for 3-6 hours depending on what it is For example, frozen meat will stay frozen longer than a tub of ice cream.

The cushions filled with polystyrene can be washed with hot water and soap and hung on the line to dry.

WONDER BOX Sewing Instructions

Click here for a Pattern

Material: 3 Meters (yards are 3″ shorter than a meter) soft cotton or broadcloth so it will conform to the shape of the pot.

(½ can be coordinated …. two colors)

19 scantly filled 1-gallon ice cream pails of Polystyrene beads (it is an insulation that looks like the tiny separate Styrofoam bits that make up the protective packing in electronics, etc.)

“Polystyrene is about the best insulating material and it is also easily washed. If you are only able to get the solid pieces which are used for packing radios etc., you can break it up by grating it.”
the booklet also says “make cushions out of large plastic bags, mutton cloth or other washable material and fill loosely with any of the following:
Polystyrene, Dried corn husks, Woolen materials, Feathers, Waste nylon materials, Flakes of newspaper, sawdust and wood shavings, Hay or other dry grasses “In Canada we have a gray ‘blow in insulation’ in our attic, it would be impossible to wash without opening the wonder box but it may be added to this list as well.

Sewing instructions:

When you sew the wonder box together you sew 2 of the 4 pieces together along the longest sides. You open each of the pairs now and place them right sides together and sew those 2 together all the way around the outside, making an awkward shaped cushion affair. Don’t forget the opening to fill through. You then repeat with the 4 bottom pieces. One pair together, sew along the longest side, then the other pair. Open them up and place them right sides together, remembering to leave openings to fill through. I am adding a loop at this point to hang this by when not in use, or dry after washing.

The narrow part of the bottom pattern is the piece you will tuck into the bigger part of the bottom to make the pouch/nest for the pot to sit into.

Hoping not to confuse the issue. If you start where the bottom pattern says 90 (degrees for the angle) and sew down the right side of the pattern and stop just after the second 11 ½ ” mark, before the pattern starts back up. That will be one of the two pairs. Do the same with the other two, put right sides together again and sew it all the way around the outside edge now, into the box or ball shape. The same goes for the top cushion, start at the 100, sew down the right and stop just after the 11″ mark. The rights sides together and sew again making the shape of the top cushion.

It will not lie flat. It will take the shape of a square cushion when it is filled with the polystyrene beads, and the bottom cushion has a cavity like a nest or pouch.

Top: Fill a little less than ½ full while the bag is hanging. Approximately 7 scantly filled 1-gallon ice cream pails.

A paper funnel works best, as the beads are very static prone. You may want to use an ice cream pail to pour from. Work with two people to fill-one to hold the funnel in and the other to pour. Spread a sheet on floor to catch beads.

Bottom: Cut 4 Fill approximately ½ full with polystyrene beads. Approximately 12 scantly filled 1-gallon ice cream pails

Once this bag is filled, tuck the small end into the center to form the pouch/nest for the pot. Find a good pot that works well in this pouch. No long handles please.

When the pan sits inside the pouch/nest of the bottom, the pan is surrounded on all sides except the top. So… that is where the top/lid comes in. It is very important to keep all of the heat inside this wonder box cooker. One of the pages and the recipes explain that the lid/top of the wonder box must go on immediately with no places for the heat to escape or it will all be for nothing.

Wonder Box Recipes

Yogurt by the Gallon

4 cups dry skim milk powder

4 quarts warm water

Mix well, heat to scald, cool to luke warm


1 cup of starter (plain commercial yogurt) or product saved from this finished recipe may be used to start a new batch. Refresh monthly with commercial starter.

Mix well, put into a gallon glass jar with a lid and place into the Wonder box.

Leave undisturbed for 12-14 hours. It will thicken more after refrigeration.

May be used plain or add your favorite fruits to flavour.

For those that can afford the calories, if the yogurt doesn’t set to your liking, add instant

Vanilla pudding. (substituting yogurt for milk)

Can be reduced for smaller batches.


2 cups quick oats

4 cups boiling water

salt to taste

Stir oats into boiling water, put lid on and place quickly between cushions of the W’box for 15 minutes or more. Stir before serving


2 cups rice

Put into

3 ½ – 4 cups of salted boiling water. NB. Because the water does not evaporate you may need less water than usual.

Place quickly into W’box, and leave for 40 minutes or longer until ready to eat.


Potatoes or root vegetables may be cooked in their skins. Bring them to a boil in a pot full of water and place quickly between cushions of the W’box for about twice as long as you would normally cook them. They may be left all day without overcooking and can be more easily peeled after cooking

Try waterless cooking by using the crisp kind of bags used for cooking roasts, etc. Submerge the bag into the water and bring to a boil. The bag should be left with opening protruding out from under the lid. Place quickly into W’box.

Chicken and other joints of Meat

Place chicken into an Oven cooking bag with desired spices, and close bag

Bring pot of water with chicken in it, to a good boil.

Quickly place into the W’box and place top cushion on.

Leave alone for at least 3-4 hours.

The chicken was put in at 9:30 in the morning before church. This single dad prepared the chicken by placing it into an oven-cooking bag. He added spices to the chicken closed the bag completely (no added moisture was added to the bag) then brought the pot of water with the chicken in, to a boil and put it all in to the W’box. We ate with him at 4:00pm. It was impressive.

Try soups, stews, what ever you can bring to a boil and then give it a try. The worst that would happen is the first time, you may have to bring things back to a boil and replace into the W’box for a second cooking time.

I was given other recipes from a group who called this “The Clever Cooker” but they looked just like any other kind of simmered recipe and the consistent instruction was leave for 3-4 hours,

Never replace a pot of half eaten or luke warm food in the W’box It should be boiled up again to prevent it going bad.

Food Storage, Not Just For Storing: THE WONDER BOX, STEP-BY-STEP PICTURES

Food Storage, Not Just For Storing: THE WONDER BOX, STEP-BY-STEP PICTURES.


Well, I finally got around to making the wonder box. When I sat down and really read the directions, they weren’t vague, I was just tired and dense. They are great and I have just added some pictures. I also had to think dimensional and not flat to get it. I suddenly remembered making stuffed toys, many years ago, and realized why I wasn’t getting it.
June 7– I have put a pork roast with mushrooms, potatoes and carrots in the wonder box. Tonight’s post will have the pictures of the process and the results . . . sure hope I don’t embarrass myself putting this one on!
1. This takes about 3 yards of fabric or one old sheet that was on the top, so it has lots of wear left in it. Thanks Bri! 2. Lay it out so that you can cut 4 of each piece. 3. Don’t forget to stop and smell the roses . . . OK, maybe just to share the table for the most important things in life. “Fun” with the little ones who are growing up way too fast.

1. I blew up the pictures to try to show the broken lines I put in on the stitching line . . . to make sure that I did it in the right places. I had a four year old “helping” me. I can get sidetracked pretty easily without help . . . and this morning was a k’nex morning besides! Remember that you just need to leave an opening for filling. I almost started filling without closing the second one. That would have been lot of fun!

1. Sew the two long sides starting at the 90 degree mark to the opposite end. I used dark thread so that you can see the stitching. I also used a stretch stitch in case it is pulled. It makes three rows of stitching that have some give and may avoid escaping beans later. They make a horrible mess. At least the bean bag I had in the 70’s and 80’s did! 2. Find the right sides, put them together and stitch all around. 3. Here is the whole thing sewn together. Turn it right side out and it is ready to fill!

1. I lucked out and had a big funnel from a strainer that I use to make apple sauce, tomato sauce and stuff like that. I taped it on to make it easier to fill the bag myself. 2. It worked really well. 3. Sew the opening up with just regular large stitches, in case the amount of styrofoam beans needs to be adjusted.

1. This a six quart pressure cooker that is 10″ in diameter & 6 ” deep. 2. 8 inches wide and 4 deep inches . I was pleased to find that the bottom was versatile. 3. I’m not sure how they got the whole thing to look so symmetrical in the internet article, but I suppose that it would cook just the same looking like it was from a Dr. Seuss book 🙂

Wonder Box Instructions (

The people over at have posted some great instructions on making a wonder box.  Here’s what they have to say:

Wonder Box Instructions  (Printable PDF Format)

A wonder box is a heat retention cooker. After you bring your food to a boil, (so it is heated throughout) using any number of cooking methods, you remove it from the heat source and quickly place the pot inside the wonder box.

The insulation of the wonder box will slow your food’s loss of heat keeping at cooking temperatures for hours. Using a wonder box reduces the amount of fuel needed to cook your meal because the fuel that would normally be used to keep your food at cooking temperatures after it has started boiling is eliminated.


  • Soft Cotton or Broadcloth Material
    • (Soft material will conform to the pot reducing air pockets or channels for the air to escape. Cotton works best as it will not melt when touching the hot surface of the pot.) I used a thin denim but will probably use a softer material next time. The fabric was 52” wide.  I used 2¼ yards. Narrower fabric may require up to 3 ¼ yards.
  • 19 Gallons (About 3 Cubic Feet) of Polystyrene Beads
    • (Bean Bag Filler, EPS Beads (Regrind), Shredded foam shipping popcorn)… Wonder Boxes have been also made with the following filler material (Wool, Feathers, Leaves, Shredded Newspaper, Saw Dust, Ground Corn Husks, Etc…)


  1. There are 2 shapes that will need to be made out of the material. The patterns are included below. One shape is needed to make the top of the Wonder Box, the second for constructing the bottom. You will need to cut 4 of each of these shapes.
  2. Once you have cut out the 8 shapes (4 for the top and 4 for the bottom), you can start the sewing process.  Take 2 top pieces and lay them front-to-front, so the exterior of the fabric of each piece is touching each other. Sew the 2 pieces together along the dotted sew-line as displayed on the patterns below. Go ahead and double-stitch it if you wish it to be more durable. Leave a small opening along one of the seams so you can add the filler.
  3. Repeat “Step 2” (Except for the opening) on the other 2 pieces of the top material.
  4. Now you will have 2 pieces (each with 2 pieces of the top sewn on one side). Place these two pairs with the exterior of the fabric facing each other. Sew these 2 pairs together so all seams are sewn together. Pull the material through the opening you left open to insert the filler material so the exterior side of the material is on the outside.  You will end up with an awkward shaped floppy pillow.
  5. Repeat steps 2-4 but for the bottom pieces.
  6. Fill the top “pillow” with 7 gallons of filling. Polystyrene beads are prone to static. Use a paper funnel and a gallon pitcher to make this job easier. Sew closed the opening left to insert the filling.
  7. Fill the bottom “pillow” with 12 gallons of filling. Sew closed the opening left to insert the filling.
  8. The narrow tongue of the bottom “pillow” tucks into the larger end to form a depression like a bowl or nest. The pot sits snuggly in this depression. The lid should fit comfortably on top sealing all gaps.
  9. The pot you select, should have a lid that seals well. The pot should also have short handles on both sides as opposed to 1 long handle. The pot could be a 4, 5 or 6 quart pot.  If the pot is too small, add a blanket around it before you set it inside the Wonder Box.

Notes: The major benefit of the Wonder Box is to reduce the fuel you need to cook your meals. By simply bringing your food to boiling temperature for 3 minutes (15 minutes for beans) and then turning off the heat and quickly placing the pot in the Wonder Box. [The important point is to make sure that the food is at boiling temperature throughout, so large pieces of meat may need to be cubed or make sure you give it time to heat thoroughly]. The heat already in your food, combined with the insulation of the Wonder Box, will allow your meal to keep cooking “at safe cooking temperatures” for hours. Remember, the less space there is around the pot, the less heat will be lost

One source stated that you can save up to 80% of your needed fuel by using a Wonder Box because the heat used for simmering is eliminated. What kind of meals can you cook in a Wonder Box? Most meals that you would cook in a Crock Pot. Meals that simmer in liquid. Rice, Chili, Stews, Soups, etc…  Your food should be entirely covered with liquid, so if you are cooking a whole chicken or a roast, make sure the food is completely covered. With a little creativity, even other foods can be cooked in the Wonder Box. For example, a few whole potatoes in an oven cooking bag placed in a pot of water brought to a boil, will cook without being water logged. The Wonder Box is a slow cooker, Rice will take about an hour, a whole chicken in 3-4 hours. Tip: cook your breakfast and lunch at the same time using the same coals. By Lunch time, your meal will be ready. You can’t burn food in a Wonder Box. As long as your food stays over 160º F, Your food can cook all day. One source recommended not using your Wonder Box while it is sitting on metal as it may some of the heat through the bottom.

The Wonder Box can be washed using hot water and soap and dried on a clothes line.

Building a Wonderbox Style Insulated Cooking Box

Adventures in Self Reliance has posted a great pattern and pictures of making a wonderbox:

Building a Wonderbox Style Insulated Cooking Box
Having enough fuel to keep warm and cook food in an emergency is an often overlooked area of preparedness. One way to preserve fuel is to use an insulated cooker like the Wonderbox. The Wonderbox was developed in the 1960’s by Anna Pearse, a South African philanthropist, for use in third world countries. It has been used for several years through her charity Compassion. In 1977, Women for Peace became the umbrella for the establishment of the Wonderbox project. So there’s your history lesson for today.

The insulated cooking box works kind of like a thermos. You put hot food in it and it continues to cook because of the insulating factor of the box. I’ll do another post on cooking in the box. For today, we’re just building it.

The pattern I have is an adaptation of the original Wonderbox pattern by our local Extension Agent Christine Jensen. Here’s the pattern:

To make an insulated cooker, you’ll need about 3 yards of standard 45″ wide 100% cotton fabric and polystyrene beads like found in a beanbag. For the beads you can check with your craft store to see if they can order them bulk or just buy a beanbag and open it up and use the beads in it. One standard adult bean bag fills two insulated cooking boxes plus a little extra. I found a beanbag at a yardsale that was nice and clean, so picked that up cheap. You would want to be careful buying used as you don’t want smoking or pet odors coming out when you cook your food–ick! You can use any fabric as long as it is 100% cotton. An old sheet, denim, etc. would all work. I got some cute fabric because I’m making mine as a gift for a friend who has a music preschool. I also thought that in a stressful situation, cute fabric might be a little pick-me-up.

I ironed my fabric to make it easier to work with, then laid out my pattern on it. I originally laid it out like this, thinking I would just cut two of each piece on each side and have a strip of fabric left over in the middle, but when I got these two pieces on it and doubled the fabric back over the top to see if I’d have enough, it came out a little short, so my 3 yards wouldn’t quite make the box if I cut it out like this.

So I laid it out differently. I folded the right edge over and placed the large bottom pattern piece on the fold, then flipped it over and repeated it on the left side.

Then I left a space large enough to cut one top piece out of the middle of the fabric and cut two more bottom pieces below that space.

I then left room again to take a top piece out of the center below the second set of bottom pieces. Below that space I cut one top piece from each side of the fabric.

After I got those two top pieces cut out, I went back up and folded the fabric right down the middle and cut the two other top pieces out of the spaces I had left.

Cutting this way, I actually had fabric left over from my 3 yards after all 8 pieces were cut out.

Now we’re ready to assemble the pieces. Get your large bottom pieces and lay two of them out right sides together. You’re going to sew starting at the top point, down the side, ending at the bottom point. It doesn’t matter which side you sew down because the pieces are mirror images of each other. Pin them together before you start sewing. Sew with a 1/2 or 5/8 seam allowance. Just pick one and stick with it for the duration of the project. It’s not like this is a fitted prom dress, it’s a pretty forgiving pattern. Repeat with the second pair of bottom pieces.

Now we’re going to attach the two pieces we just made to each other. Open them up and match the two pieces, right sides together. Match up the raw edges, pin together and sew, leaving an opening near the top to turn and fill it.

Now, as is standard with sewing anything with corners, I trimmed and clipped my corners before turning the whole thing right side out via the opening.

Now set the bottom aside and assemble the top. Lay out two top pieces, right sides together and sew from the top point, down one side to the bottom point. Repeat with the second pair of top pieces.

Then open the two top pieces up and pin them together, matching raw edges, and sew around, leaving an opening at the top to turn and fill through. This is just like the bottom pieces we sewed together, just a little different shape. Trim/clip the corners and turn it right side out. To find the shape the top and bottom are supposed to be, find where the corners all came together to make an X and flatten it out. That is the top or bottom. On the top pieces, it won’t matter which side is up. The bottom piece, you want the big X down. The smaller X will be the part that squishes inside the box to make a pocket for the pot. See the X?

Now we’re going to fill the bags with the polystyrene beads. Get in a place that is easy to clean up. The beads WILL go everywhere. You can use a spray bottle with water in it to cut down on static–it won’t hurt anything. This is easier with a friend. Make a funnel out of an old milk jug or something to help get the beads in. I used a file folder and taped it into a funnel shape. It worked pretty well. Fill the top about half full of beads. That’s plenty. Really.

Fill the bottom about half full also. I put mine in the box I was going to use for it and made sure the largest pot I’d be using fit in it. Then I stopped putting beads in it.

Once your pieces have the beads in them, sew the openings shut. You can hand sew them, but I don’t believe in hand sewing unless it’s entirely necessary, so I turned the edges in toward each other, pinned them together and top stitched them together.

There should be plenty of slack to get these openings sewed shut with your machine. Now stick it in a box–a banana box or one of equivalent size works great–put the top on, and you’re ready to cook! (Yes, it’s supposed to be a little loose and sloppy looking–that’s so it can conform to your pot shape/size easier.)

Cooking instructions here. 🙂

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