Let’s Make Sense of Thermal Cooking Cookbook

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https://www.thermalcooking.net/

What is a Thermal Cooker?

ThermalCooking.net has the answer:

​The term “thermal cooking” simply means “cooking with heat.” Thermal cookers are cooking appliances that cook by retaining heat. 

Thermal cookers are like a big crock pot, cooking food slowly over time. While slow cookers require constant electricity, thermal cooker utilize heated (boiling) food to complete the cooking process.

What is all the hype about trapping heat to cook your food? Thermal cookers are portable, quick, and convenient. They save energy, are simple to use and easy to clean, can retain both heat and cold, and trap nutrients and flavor inside. 

The first step in retained heat cooking is to bring food to a boil. The pot of boiling food is then placed inside an insulater. The food will continue to cook as the temperature of the food slowly drops over time. The result, when done correctly, is food that will maintain safe-serving temperatures for eight hours or longer.

Buy Thermal cooker or assemble them using boxes, coolers, blankets, or pillows and a heavy pot, making thermal cooking accessible to everyone.

Wonder Box Cooker

The Wonder Box Cooker recipes and instructions originated from a booklet published by “Compassion” of South Africa in 1978,1979 and 1980. “Compassion” registered name Wonder Box and the logo of the kneeling figure. This information may be freely quoted, acknowledgments being made to “Compassion”

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

Add

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.

Porridge

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

Rice

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.

Vegetables

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.

Comments on cooking bread and other things in a wonderbox cooker

Comments on cooking bread and other things in a wonderbox cooker:

Steamed bread in a wonderbox — turned out fabulous. We left it in the hot water to rise then boiled it for ten minutes and kept it in the wonderbox for 1 hour and 45 minutes. Here is some detail about the wonderbox bread…

I put the whole wheat bread dough in a oiled cereal bag (the waxed-
paper-like inner lining bag in boxes of cereal). Then I twisted up the
end and closed it with a twist tie. I then placed this bag inside a
Reynolds oven bag and twisted up the end of that bag. Rather than
putting the twist tie on at that point, I folded over the twisted end,
making a loop and then secured it with a twist tie, creating a double
reinforcement and less probability of water leaking in. I have heard
it being done in a Zip-loc bag as well, but I was pleased with the
cereal bag and oven bag. When picking a bag, you are concerned with
its ability to withstand the heat of boiling and ability to get a tight
seal when closing as water seeping into the bread will ruin it.

Then I put the dough in a pan of hot water to rise. After it had
risen, I boiled it for ten minutes and then placed the pan with the
dough in it and with the lid on in the Wonder Box. I left it there for
1 hour and 45 minutes. It was perfect. The bread comes out round and
is not browned, but very moist and light. You will not get overdone,
dry bread this way.

BREAD Recipe:

4 cups whole wheat, brown or white flour, or mixed as you wish

1tsp each yeast and sugar mixed, added to ¼ cup warm water

1 cup warm water with 1 tsp salt added

Mix and knead the dough (or add ¼ cup warm water and merely stir it well). Roll the dough in dry flour and place it in an ordinary (crisp, cereal) plastic bag which has had a little oil rubbed around inside.

To reduce time needed for this it can be left submerged in warm water in the wonder box.

When it has doubled its size, it should be brought to boil in the water and boiled for about 10 minutes. Transfer the bread in the pot of water to a wonder box for an hour to finish cooking when it should have a soft “crust”.

I have fielded numerous requests from readers who are making their own wonder boxes, and wanting to know what type of material would be best for the cushions.

Cushions have to be of a soft material that will squish firmly around the top, bottom and sides of your wonder box. Another idea is to use the inners of old, flat pillows.

Another example of making bread in a wonderbox

I have been baking bread in a wonderbox for awhile now. My recipe is for 2 loaves (whole wheat). I put one in the wonderbox and one in the oven. I raise the bread by putting it in a cereal bag that has been sprayed with cooking spray. I put a twistertie on that and then put that in an oven bag, twist it up and then double the twisted part over and put on the twister tie. That part looks like a loop. Anyway I put the bagged dough in a pot of warm water to rise. When it has doubled, I bring the whole thing to a boil and boil for 10 minutes. Then put the whole thing in the wonderbox and go away. Once it was in there for over 8 hours and the bread was still warm. I think the least amount of time has been one hour.
The bread does not have a crust and is usually oval, but it is moist and delicious. In fact when I have people try a bit from the oven baked and the wonderbox, they prefer the wonderbox bread hands down.
So do I.
I have reused the cereal bag. I make my own cereal so I don’t have those kind regularly. I’ve tried ziploc bags for the outside and sometimes they pop open from the rising bread. If it gets under water, the bread is ruined.

Bean Soup
I made bean soup. I soaked the beans over night, then boiled them 20 minutes, and after a couple of hours in the wonderbox, I took them out to put some bean flour in to thicken it and reheated it for another 20 minutes before putting it back in. All together it was probably 6-7 hours in there, but no burning or sticking, and I left it that long because that was when I was using the soup…

BTW, I was using the ice box cooler for the thermal outer container which I placed the bean pot inside. I first wrapped the bean pot in a wool blanket and then put a pillow on top of the pot and blanket before closing the cooler lid. I have also been using a half of a mylar space blanket in the wonderbox and the ice box cooker both to retain heat, but also to keep the wonderbox clean and dry and to keep the wool blanket dry. I think that really helps.

Wonderbox Pattern with instructions on how to make

Here are a few images which contain a pattern to make your own wonderbox.

It’s much like a beanbag chair of sorts made from fabric and filled with styrofoam beads.