The commercial fireless cooker costs more than does the home-made one; on the other hand, it is likely to be more durable, it seldom has any absorbent material exposed to the odor and the steam from food, the cooking compartment can be kept clean more easily, and it is frequently provided with a ventilating valve or some such device that makes baking and roasting possible. However, the home-made fireless cooker has proved to be wholly satisfactory for such foods as cereals, vegetables, dried fruits, custards, fowls, and certain cuts of meat.

There is practically no danger of fire from a home-made cooker unless very hot radiators are used. Since thermometers are not used in the average home, and the radiators may be heated to an unnecessarily high temperature, it seems safest to advise against the use of radiators unless the insulator is not inflammable. Under no conditions can a very hot radiator above the food be safe, because it is too near the muslin of the cushion. While baking is impossible without the use of radiators, there are sufficient other processes for which the homemade cooker may be used, to warrant the trouble and the small cost of making one.

The cost of a home-made fireless cooker may range from about $1.50 to $8.00 or more, depending on the materials used. If several sizes of aluminum pails with clamps are bought for food containers, the cost may equal that of a small commercial cooker. In buying a fireless cooker the following points should be considered: insulation, exterior case, interior lining, cooking utensils, vent valve, hot plates, locks and hinges, size, and cost.

* Canon, Helen, and Brewer, Lucile. The Fireless Cooker and Its Uses. Cornell Reading-Course for the Farm Home, Bull. 95.

The following materials and utensils are needed for making a fireless cooker (Fig. 49):

For the case, or cabinet: A wooden box, a trunk, an ice box, a galvanized iron ash-can, a wooden candy-bucket, or the like. Any kind of case that is used should be provided with a tight-fitting cover. If an ordinary box is used, it should be of sufficiently heavy material to permit the use of good hinges and fastenings.

Fig. 49. - Diagram of a home-made fireless cooker. A, outer case; B, cushion; C, cooking compartment; D, food container; E, packing material.

For the lining of the case: Sheet asbestos 1/8 inch thick, or heavy wrapping paper.

For packing material: Ground cork, sawdust, excelsior, mineral wool, paper torn in small pieces and crumpled, powdered asbestos, shavings, straw, hay, wool, cotton batting, or some such non-conducting material. Mineral wool and powdered asbestos are both good non-conductors of heat, and they have the additional merit of not being inflammable; but they are harder to work with than are the other materials. Gloves should be worn by the person doing the packing, and care should be taken not to allow the material to enter the nose and the mouth.

For the cooking compartment: A deep bucket or kettle of agate, galvanized iron, or tin, of such a size that there may be a space of at least three inches between the case and the top, the bottom, and the sides of the bucket. This bucket or kettle should have a tight-fitting, flat cover. In place of a bucket, two thicknesses of 1/16-inch sheet asbestos or heavy wrapping paper may be shaped to form the cooking compartment; but a bucket is more durable and can be kept in a more sanitary condition.

For the cooking utensil: A covered kettle or bucket of agate or aluminum, of a size suitable for the amount of food ordinarily to be cooked in it. The utensil should be durable, and free from crevices and seams in which particles of food and harmful micro-organisms may lodge, and it should be supplied with a tight-fitting cover that can be clamped down. Seamless aluminum is perhaps most commonly used for this purpose. Special fireless-cooker utensils can generally be obtained from a local hardware dealer or a firm that manufactures fireless cookers.

For the collar to cover the packing material: A piece of zinc, cardboard, sheet asbestos, or muslin, of such a shape as to fit the space between the case and the bucket that serves as the cooking compartment. Zinc is good for this purpose because it does not tear with constant use as do the other materials, it can be washed, it does not rust, and it is not inflammable.

For the cushion: Heavy drilling, denim, or muslin.

For the hot plates, if desired: Flat stones, stove lids, or special soapstone or metal radiators. Most foods can be cooked without the use of hot plates or radiators, but a higher temperature can be reached and a cooking temperature prolonged by their use. Hot plates should never be used unless the cooker is packed with non-inflammable material, such as mineral wool or asbestos.

Directions for making a fireless cooker are as follows:

(1) Line the case and its cover with sheet asbestos of 1/8 inch thickness. (2) Pack into the bottom of the asbestos-lined case a layer at least 3 inches deep of whatever packing material is to be used. (3) Place the bucket that is to form the cooking compartment on the layer of packing material in the bottom of the case. Pack the space between the case and the cooking compartment closely with more of this material, filling the space to within Y2 inch from the top of the bucket. (4) Make a collar of any of the materials suggested, to cover the exposed surface of the packing material between the case and the cooking compartment. (5) Make a cushion of some of the materials suggested, which when filled with the packing material will be at least three inches thick, and will, as exactly as possible, fit into the space between the top of the cooking compartment and the top of the case. Cut from the material two pieces of the desired shape and size, and put them together with a straight strip of the desired width, with extra allowance for seams.