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  • Writer's pictureCindy Miller

Types of Thermal Cookers

Updated: Nov 14, 2020

Like so many other traditional skills, the art of thermal cooking has been virtually lost to our society.

For most of my life, I had no idea that such a wonderful device as a thermal cooker existed.

After discovering the thermal cooker and researching it, imagine my surprise to learn that thermal cooking is not a new concept. In fact, thermal cooking, or retained heat cooking, has been around for hundreds, if not thousands, of years.

As I learned, studied and experimented with thermal cooking, I discovered a wide range of uses for the cookers.

I love the get-up-and-go freedom the cooker gives me. I find myself using the thermal cooker just as much for everyday use as I do for special occasions. I love the money saving aspects the thermo cooker offers, from fuel savings to the grocery bill.

The more I experiment, the more I am convinced that everyone should own a thermal cooker!

Stainless Steel Cookers

Foam Units

The Saratoga Jacks thermal cookers are excellent at facilitating retained heat cooking.

The Saratoga Jacks thermal cookers include two quality Stainless steel inner pots, one nestles down inside of the other.

There are 3 different Saratoga Jacks thermal cookers available.

1- The Regular 7 liter Saratoga Jacks thermal cooker. The larger 7-liter pot which comes with this cooker has a heavy stainless steel base, the inner 2.5-liter pot in this unit has a thin stainless steel base.

2- The 7-liter Deluxe Saratoga Jacks thermal cooker, on the other hand, has the heavy bottom triple clad stainless base on both the large 7-liter pot and the inner 2.5-liter pot.

3- The 5.5 liters Saratoga Jacks thermal cooker, it is the same as the Regular, the large 5.5-liter pot is heavy, the inner 1.5-liter pot is light weight. 

Two pot thermal cookers help increase the versatility of the thermal cooker. By having two pots it possible to prepare and serve two dishes at the same time or to just use the large pot and make one nice big pot of food. These cookers will retain heat for 8 hours when 75 - 80 % full and at a full boil. I also like using them for container cooking.

Quality foam unit, versatility, and affordability are my favorite things about the Saratoga Jacks stainless steel thermal cookers.  

Vacuum Sealed Units

Dave Knowles of Mr. D Thermal Cooker has a new 3.5-liter thermal cooker. I was so excited when I could finally give it a try!

The 3.5-liter is a size I have been missing. Because of the lack of thermal mass 3.5-liter, thermal cookers can not retain heat as long as larger units. When I saw what Mr. D had done to counter this issue I was very excited to try it. The Mr. D 3.5-liter thermal cooker has a cast iron plate built onto the bottom of the inner pot. This helps maintain the heat for a longer period. 

Just that one point had me very excited to check out this cooker. What I found when I received it was a high quality, dependable thermal cooker. The handles are secure and fold down into the lid when not in use. The latch secures very well, and both pots the 3.5-liter and the 1.5-liter have the nice triple clad bases. There is one thing I pay careful attention to when using my Mr. D cooker with the cast iron base. Where the base is attached food tends to want to stick a little bit. I just make sure to stir often and keep the food from sticking while it is cooking.  

I can see how this vacuum cooker has taken over the sales of his other cookers. Nice job Dave, great product. For more information, you can go to his site at:

The first thermal cooker I used was this Shuttle Chef. When my mom was first introduced to a thermal cooker she immediately could see the benefits of using them in her preparedness plan. Lucky for us we use them all of the time now.

A shuttle chef is made by Thermos and was first introduced in 1989. It seems as though we have a shuttle chef and thermos to thank for the term "thermal cooker" instead of "retained heat cooking apparatus", "hay box" or "fireless cooker".

Shuttle Chef has come out with several new designs and sizes of thermal cookers. I have only tested the 4500 model my mom owns. I like the Shuttle Chef it does retain heat well, although I usually don't turn to it first. I think it is because mine did not come with the inner pot. They are available with multiple pots. Shuttle Chef thermal cookers are a very good product, their price can be prohibitive to some. 

Fabric Thermal Cookers

The HopeSaC

HopeSaC stands for Hope, Service, and Charity.

A HopeSaC is a fabric thermal cooker which I designed to better serve people in need.

The HopeSaC cooker has excellent at heat retention and is an excellent option for those who would like to make one themselves. 

HopeSaC patterns raise money for The HopeSaC Project.

Wonder Bags

A Wonder Bag is another device or appliance which facilitates retained heat cooking. A Wonder Bag is made from fabric with a cut-up foam insulator. A pot will need to be supplied when using fabric thermal cookers. I would suggest using a nice heavy pot to help retain the heat and maximize the efficiency of the fabric cooker. It is possible to use a variety of pots and baking dishes in different shapes and sizes. With the Wonder Bag, the string around the top is cinched down tight, this helps the portability of the cooker.

These Wonder Bags come out of Africa. A great thing about the Wonder Bag is that with every purchase a portion is donated toward a Wonder Bag for families in need.

Wonder Oven

A Wonder Oven is also used for thermal cooking. A wonder oven is basically two pillows with a space sewn in the center to hold a pot of hot boiling food.

There are pros and cons to using all types of devices and the wonder oven is no exception. The biggest advantage a wonder oven has is that it is economical. They are usually made with polyurethane beads but can also be made with wood chips or any other 'non conducting' filler. Refer to my Insulators Video for hints on what to look for when choosing an insulator.

Wonder Ovens are bigger and bulkier than most other thermal cookers. I would suggest using them in a tote, not only will it help in transporting the cooker, but the tote will add another layer of insulation. 

My friend Megan is the master at using Wonder Ovens, her site MyFoodStorageCookbook is packed with information on making a wonder oven and recipes to use in it. Her recipes can be used in any type of thermal cooker you may own. 

DYI Thermal Cookers

When I first hatched the idea of a website, my goal was to share all kinds of thermal cooking methods. Thermal cookers have broad usage, from family dinners to times of emergency. A knowledge of how to utilize household items to save time and money when cooking could come in handy. 

Finally, here it is. I will add articles with detailed instructions, pictures, and videos on all types of thermal cookers as I get them done. Signup for the newsletter below for notifications. 

Thermal cooking can be accomplished in many ways by using items that most have around the house. The principles are all the same. My Back 2 Basics video gives more detailed information on achieving success. But basically, make sure your food gets to a boil. The larger and heavier the pot the longer the food stays hot. The better the insulation, the longer it stays hot. 

The ground is an excellent insulater and a dutch oven is a nice and heavy pot, together they make a very efficient thermal cooker. Baskets and blankets also work but have larger likelihood that they will not be as efficient as some of the other methods. But the point is, they still work. If there was an emergency, knowledge of how to feed the masses could be the difference between life and death. I choose life.  


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

Purchase Retained Heat Containers, Cookbooks and More here!

Learn to make your own HopeSac for thermal cooking: https://thermalcooking.vipmembervault...

OTHER VIDEOS YOU MAY LIKE: Ideas to Use your Thermal Cooker for a Whole Week:

Join us HERE for the Thermal Cooking Online Course!!! https://thermalcooking.vipmembervault...

Live Digital Cookbook: https://thermalcooking.vipmembervault...




DISCLAIMER: Links included in this description might be affiliate links. If you purchase a product or service with the links that I provide I may receive a small commission. There is no additional charge to you! Thank you for supporting The HopeSaC Project so we can continue to provide service to those in need!

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