Fireless cookery emerged in the U.S. around the turn of the 20th century, and judging from the number of makers and the frequency of advertisements that followed, it seems to have caught on for a while.
It was a simple concept. Food was put into a specially designed kettle with a minimum amount of liquid and brought to a boil, and the kettle was then put away in a well insulated container where the heat of the liquid finished cooking the food.
When steaming or boiling it is essential to have your cooker kettle and its contents very hot. Put it into the box as quickly as possible. Close the box immediately and do not open it again until the food has had time to cook. If for any reason you must open the box before the food is cooked, the kettle must be reheated or the cooking will not be done. – Lovewell, Whittemore, & Lyon. 1908.
Except in some specially made purchased models in which heavy plates of iron or soapstone were heated and placed into the openings underneath and on top of the kettles, no additional heat was used in the cooking process.
Numerous early 20th century accounts say crude home-made versions originated in Norway and spread to other parts of Europe before being introduced in the U.S. The first documented account of a commercially made cooker was its exhibition at the Paris Exposition in 1867, but it wasn’t until the late 1890’s that advertisements began appearing in the U.S.
At that Exposition, three medals were awarded to Sorrenson’s patent for the Norwegian self-acting cooker. – The New York Medical Journal. Vol. X, 1870.
The cookers were well known to Norwegian housewives, “but it is only recently  that its wonders have become rather widely known and talked about in America”. – Mitchell, Margaret. The Fireless Cook Book. 1913. NY.
Ellen Alden Huntington wrote in 1908 that the Consular Report from Germany credited the use of the fireless cooker to Mrs. Bach, wife of the president of the Industrial School at Frankfurt, in 1892. This account alone is hardly enough to say for sure Mrs. Bach was the first to use the method, but it does substantiate its use in Germany at the time of publication. – Huntington, Ellen Alden. The Fireless Cooker. 1908. Madison, WI.
The previous source went on to elaborate that Mrs. Bach’s cookery method evolved from the early German practice of starting a kettle of soup to boil and then removing it from the heat and wrapping it in a featherbed overnight where it slowly continued to cook.
The earliest cookers were wooden boxes or barrels insulated with hay and for that reason were known as hay boxes or hay box cookers. They have also been called Norwegian cooking boxes.
Some models came with specially made cushions which were placed on top of the cooking kettle between the lid of the kettle and the lid of the cook box. These cushions were for extra insulation to hold in the heat of the cooking liquid.
The materials used as insulation inside the cooking boxes included, at various times, hay, straw, feathers, pillows, wood shavings, cut-up or crumpled up paper (usually newspaper), wool, excelsior, ground cork, saw dust, asbestos, and Southern moss. The latter was found naturally only in the deep South, however, it could be purchased from upholsterers in the northern states.
Because the kettles were exposed to longer periods of moisture during cooking at lower temperatures certain metals tended to rust quickly, namely iron and tin. Most foods were cooked with salt as a seasoning and longer exposure to the salt also hastened rust in kettles of iron and tin. Earthenware kettles were a good choice for use in the cook box, but they were prone to breakage while initially bringing the foods to a boil on the stove before placing them in the box.
That left well-enameled pots and cast aluminum pots as the best suited for fireless cookery. Ironically, that information also helps to date the fireless cooker method to the late Victorian era as those materials were not commonly used until late in the century.
Porcelain, granite-ware, aluminum, crockery and stone-ware are all excellent. Tin rusts and should be avoided in steaming…Stone jars are quite perfectBecause they hold heat so well. With care they may be used instead of Kettles over a flame. - Lovewell, Whittemore, & Lyon, 1908.
The advantages of the cooking system were economy (less fuel was used for cooking food), in hot weather food could be cooked without heating the house and making it uncomfortable for the occupants, there were no foul cooking odors (such as cabbage) in the house because the food was sealed in an airtight container while it cooked, and the food tasted good after cooking long hours at low temperatures.
There is no reason why the housekeeper of today cannot meet the hot and sultry days of July and August with as perfect ease as she does December and January, if she but uses this method of cooking. Bring cereal to a boil, put it in the box, and it is ready in the morning. Home Science Magazine. Vol. 22, No. 11, 1906.
Cereals which required much longer cooking time than they do today could be started before bedtime, put into the fireless cooker, and left to cook overnight so that they were hot and ready to serve for breakfast the next morning. This allowed the cook a few more minutes of sleep before beginning her day.
The fireless cooker was an ideal place for yeast bread dough to rise because the temperature remained constant and the dough wasn’t exposed to blasts of cool air when a door was opened.
In 1914, the fireless cooker was still looked upon as a modern invention by Americans, but Bertha Austin wrote that it operated along the same principal as the brick oven making it a modern interpretation of an old concept. A brick oven was heated to a high temperature, but the fire and coals were removed before the food was put in, and it was the heat retained in the walls of the oven that cooked the food.
One cannot help but make the comparison between the fireless cooker and a crock-pot. Both are used by placing ingredients into the pot hours before they are to be served and left to slowly stew for several hours before being served. The methods differ in that the crock-pot has a constant source of heat whereas the fireless cooker cooks the food without providing any additional heat.
There were commercial models made of metal inside and out, and wooden models of varying quality cabinetry. The better versions of the latter were considered a piece of furniture much like any other item of furniture in the home.
The cookers were also marketed toward persons other than housewives.
Again, fishermen, pilots, and others whose small vessels are not generally so constructed as to enable them to procure hot food while at sea, may easily do so by taking out with them in the morning an apparatus prepared before their departure. It is, in short, a thing for the million, for rich and poor; for the domestic kitchen, as well as for persons away from their homes. It cooks and keeps food hot, just as well when carried about on a pack saddle, on a cart, or in a fisherman’s boat, as in a coal-pit or in a housewife’s kitchen. The New York Medical Journal. Vol. X, 1870.
The fireless cookers were used extensively in Britain during the World Wars in an effort to reduce the amount of fuel needed to prepare food. An account published in 1908 also claims the U.S. Army experimented with using the fireless cookers at government posts and in the field.
Their principal value in the army is as a time saver. Breakfast is prepared during the evening thus avoiding the necessity of the cook’s rising before daylight. – Lovewell, Caroline Barnes, Whittemore, Frances Dean, and Lyon, Hannah Wright. The Fireless Cooker: How to Make It, How to Use It, What to Cook. 1908
I have read speculative comments that fireless cookers were used by settlers traveling west in wagon trains, some authors have even gone into detail about how food could have been put into the cooker before bed and been ready to eat upon rising next morning, or put into the cooker early in the morning and be ready to eat when the wagons stopped and made camp in the evenings.
There is a huge problem with such speculation – by the time the cookers were advertised and introduced to American markets, the railroads were complete and had become the primary mode of transportation for those traveling west. The first transcontinental railroad was finished in 1869 [two years after the patents were granted at the Paris Exposition], and by 1883 the Northern Pacific Railroad had reached Portland, Oregon. It would be several years yet before advertisements for the cooker appeared in American newspapers and magazines.
Fireless Cooker was also a name attached to the earliest electric ranges after the turn of the century. Campbell’s model had two burners on top, an oven in the middle, and a receptacle into which fit two round kettles, in much the same manner as the non-electric fireless cookers.
The fireless cooker may still be a viable cooking method for those who want to live a more self-reliant lifestyle, however, and the pros and cons as to its use remain the same as they were at its introduction. With sweltering summer days upon us, keeping cool while cooking meals is a timely message.