Mr D's Thermal Cooker

John Adams
Thursday, 10th February 2011

A cunning 21st century adaption of the hay-box which can save up to 80% of the fuel used to cook conventionally.

With the need to conserve energy where we can and fuel prices predicted to soar, Mr D's Thermal Cooker couldn't have come at a better time. This is a 21st century adaptation of a hay box but instead of being a bulky insulated box, this is a neat stainless steel unit with a highly efficient vacuum outer wall. It consists of two main parts: the lidded inner pot which is used to cook in, and the thermal walled outer which is used to conserve the heat. 

Shown with the outer lid open revealing the inner stainless steel cooking pot.

 Despite its apparent modest size, it can be used to cook for quite large numbers. I tried it out by cooking beef in beer for four (see above), and a game casserole for eight and it could easily have done ten portions. While I have only so far cooked stews and casseroles, it can be used for a wide range of dishes from soups to desserts and with suitable accessories it can even be used to make bread and cakes.

The cooking principle for most dishes is the same. The ingredients are prepared and cooked on the stove top in the heavy bottomed stainless steel inner pot. When the dish is complete it is brought up to boiling point and then simmered on a medium heat for 10 minutes or so. By now all the contents should have reached an even temperature and the inner pot can be removed from the heat and placed in the thermal outer and the lid closed. The food is now left to cook without additional heat for the next one to six hours depending on the recipe.

Making a game casserole in the thermal cookers inner cook potThe food I made was really delicious with nice rounded flavours from the slow cooking, similar to what you get using the slow oven on a range but without the energy costs. In fact it can save up to 80% of the fuel you would normally use. It has other uses too, being so thermally efficient it can be used to keep food or drinks either hot or cold for up to eight hours. You can use it at home (even on induction hobs) or take it camping, caravanning or sailing. A very versatile and efficient addition to any kitchen. 

Mr D's Thermal Cooker is available from Green Shopping.

A review of the accessories for the Thermal Cooker - a cake tin and a bread tin - is available here.