Where fuel is scarce, the fireless cooker is a boon, since it keeps food cooking with a small amount of heat stored in hot stones. Thick layer of insulating material around the pot prevents heat loss.
Cut 10 cm wide strips of newspaper, several layers thick. Roll each into a cylinder with a central hole thicker than a pencil. Pack these on end into the bottom of the outside container (See Figure). They will support the well, stove, and cooking pot. Put the well or the inside container in place and pack the insulation (newspaper, wool, cotton, sawdust, etc.) around it to within 1 cm of the top.
To make a concrete heating stone, place a 5 cm cardboard band or collar on heavy paper or board to form a circle-the size of the stone desired. Mix 4 cups each of cement and sand (0.95 litre). Then pour in enough water (l.5 cups to form a stiff mush). Fill the collar, casting in a wire handle for lifting the hot stone. Let the stone stand for 48 hours, then remove the collar, place it in cold water and boil for 30 minutes. Cool it slowly.
Very little water is used in the fireless cooker as there is hardly any loss by evaporation. Most foods are brought to a boil and cooked for 5 minutes on another stove. The heating stone is heated and placed in the cooker. Then the covered cooking pot is set on the hot stone in the cooker and the lid is placed on the well.
1. The cooker's lid should be left partially open.
2. Heating stone and cooking pot should be clean and dry.
SOURCE: Intermediate Technology Development Group, 9 King Street, London WC 2E, United Kingdom