Stove
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A stove is a heat-producing device. Typically the word is used to refer to a kitchen appliance used for either generating warmth or for cooking. In British English the term cooker is normally used for the cooking appliance, and stove for a wood or coal burning room heating appliance.
There are many types of stoves. In the common experience, a kitchen stove is used to cook food, and refers to a device which has both burners (also known as a cooktop, or in British English as a hob) and an oven.
Glass_ceramic_cooktop.jpg
Stoves may generate heat by:
- burning natural gas
- electrical resistance
- burning wood (most common in developing nations). Burning wood for "ambiance" and in barbecues is fairly common, and is considered "the fastest-growing form of pollution".
- burning heating oil (mainly used for always-on stoves.
- burning solid fuel (usually coal and becoming less common due to concerns about environmental pollution)
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Common features of modern stoves
Modern stoves typically have from three to six burners or hotplates, an oven, and knobs for controlling heat on burners, which may be located on the backsplash, on the cooktop, or on the front of the stove closest to one's hips.
Middle to high end models also may feature locking mechanisms for the oven door, automatic cleaning mechanisms that raise the oven temperature to over 260 degrees Celsius (500 degrees Fahrenheit) and reduce accumulated food spills to ash, one or more timers, a digital display, and may even be programmable such that they start and stop heating at preset times.
History
Early stoves in the Western World
In Europe, the history of the kitchen stove begins in earnest in the 18th century. Before, people cooked over open fires fuelled by wood, which first were on the floor or on low masonry constructions. In the Middle Ages, waist-high brick-and-mortar hearths and the first chimneys appeared, so that one didn't have to kneel or sit anymore to cook. The fire was lit on top of that construction; the space underneath was used to store and dry wood. Cooking was done mainly in cauldrons hung above the fire or placed on trivets. The heat was regulated by placing the cauldron higher or lower above the fire.
Open fire has three major disadvantages that prompted already 16th century inventors to look for improvements: it is dangerous, produces a lot of smoke, and the heat efficiency is poor. Attempts were made to enclose the fire to make better use of the heat it generated and thus reduce the wood consumption. A first step was the fire chamber: the fire was enclosed on three sides by brick-and-mortar walls, covered by an iron plate. This technique also caused a change in the kitchenware used for cooking, for it required flat-bottomed pots instead of cauldrons. Only in 1735 the first design that enclosed the fire completely appeared: the Castrol stove of the French architect François Cuvilliés was a masonry construction with several fireholes covered by iron plates with holes. It is also known as a stew stove. Towards the end of the 18th century, the design was refined by hanging the pots in holes through the top iron plate, thus improving heat efficiency even more.
Early stoves in East Asia
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Chinese and Japanese civilisations had discovered the principle of the closed stove much earlier. Already from the Chinese Qin Dynasty (221 BC - 206/207 BC), clay stoves that enclosed the fire completely are known, and a similar design known as kamado (かまど) appeared in the Kofun period (3rd - 6th century) in Japan. These stoves were fired by wood or charcoal through a hole in the front. In both designs, pots were placed over or hung into holes at the top of the knee-high construction. Raised kamados were developed in Japan during the Edo period (1603 - 1867).
Iron stoves
In the 18th century the first iron stoves appeared. An early example is the Franklin stove, a wood burning stove said to have been invented by Benjamin Franklin in 1742. It had a labyrinthine path for hot exhaust gases to escape, thus allowing heat to enter the room instead of going up the chimney. The Franklin stove, however, was designed for heating, not for cooking. Benjamin Thompson at the turn to the 19th century was among the first to present a working iron kitchen stove. His Rumford stove used one fire to heat several pots that were also hung into holes so that they could be heated from the sides, too. It was even possible to regulate the heat individually for each hole. His stove was designed for large canteen or castle kitchens, though. It would take another 30 years until the technology had been refined and the size of the iron stove been reduced enough for domestic use. Stewart's Oberlin stove was a much more compact iron stove, patented in the U.S. in 1834. It became a huge commercial success with some 90000 units sold in the next 30 years. In Europe, similar designs also appeared in the 1830s. In the following years, these iron stoves evolved into veritable cooking machines with flue pipes connected to the chimney, oven holes, and installations for heating water. The originally open holes into which the pots were hung were now covered with concentric iron rings on which the pots were placed. Depending on the size of the pot or the heat needed, one could remove the inner rings.
Gas and electric stoves
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All these stoves were fired by wood, charcoal, or coal. The first gas stoves were developed already in the 1820s, but these remained isolated experiments. (James Sharp in Northampton, England, patented a gas stove in 1826 and opened a gas stove factory in 1836.) At the world fair in London in 1851, a gas stove was shown, but only in the 1880s did this technology start to become a commercial success. The main factor for this delay was the slow growth of the gas pipe network. The first gas stoves were rather unwieldy, but soon the oven was integrated into the base and the size reduced to fit in better with the rest of the kitchen furniture. In the 1910s, producers started to enamel their gas stoves for easier cleaning. A high-end gas stove called the AGA cooker was invented in 1922 by Swedish Nobel prize winner Gustaf Dalén. It is considered to be the most efficient design and is a much sought after kitchen "must have" in certain circles—despite the hefty price tag.
The AGA, and similar products such as the Rayburn Range are examples of always-on stoves which continue to burn fuel even when cooking is not being performed. Stoves (or ranges as they are also known) such as these are often used instead of boilers or furnaces to supply hot water and central heating to the rest of the house.
First attempts at building electrical stoves were made in the 1880s, but its real debut was at the Chicago World's Fair in 1893, where an electrified model kitchen was shown. But like the gas stove, the electrical stove had a slow start, partly due to the unstable technology, and partly because first cities and town needed to be electrified. By the 1930s, the technology had matured and the electrical stove started to slowly replace the gas stove, especially in domestic kitchens.
The electrical stove technology has developed in several successive generations:
- The first technology used resistor heating coils which heated iron hotplates, on top of which the pots were placed.
- In the 1970s, glass-ceramic cooktops started to appear. Glass ceramic has a very low heat conduction coefficient, but lets infrared radiation pass very well. Electrical heating coils or infrared halogen lamps are used as heating elements. Because of its physical characteristics, the cooktop heats quicker, there is less afterheat, and only the plate heats up while the adjacent surface remains cool. Also, these cooktops have a smooth surface and are thus easier to clean, but they are also markedly more expensive.
- A third technology, developed first for professional kitchens, but today also entering the domestic market are induction stoves. These heat the pot directly through electromagnetic induction and thus require pots and pans with ferromagnetic bottoms. Induction stoves also often have a glass-ceramic surface.
The iron hotplate technology is still in widespread use, although newly equipped kitchens nowadays usually get a stove using one of the later technologies.
Electrical oven technology has also advanced: in the convection oven, a stream of hot air is used for heating food instead of the heat produced by coils directly as in a conventional electrical oven.
Gas and electric stoves are the most common today in western countries. Both are equally mature and safe, and the choice between the two is largely a matter of personal preferences and of what installations already exist in a house: if a house has no gas supply, adding one just to be able to run a gas stove is an expensive endeavour. In particular, professional chefs often prefer gas stoves, for they allow them control the heat more finely and more quickly.
See also
External links
- History of iron stoves (http://www.anderweit.de/I_anderweit/I_4_Programm/3931824160.pdf) – in German.
- The History of Stoves and Ovens (http://inventors.about.com/library/inventors/blstoves.htm) From About.com
- How Stoves Work (http://www.repairclinic.com/0088_13_3.asp) Article by RepairClinic.com
- Early Chinese stoves (http://www.yutopian.com/cooking/history/), with images.
- Early Japanese stoves (http://www.aisf.or.jp/~jaanus/deta/k/kamado.htm), with a good image.de:Herd