| 
HOME > Toshiba's History > TOSHIBA Firsts of Their Kind > Automatic Electric Rice-Cooker
Toshiba Firsts of Their Kind
Automatic Electric Rice-Cooker
| The idea
of cooking rice with electricity was first conceived in the age
of westernization during the Meiji era, and products called "electric
stoves" and "electric rice tubs" were produced experimentally at
the end of the Taisho era (mid 1920s). These were stoves and tubs
to which heating coils were attached. In the late 1940s, Mitsubishi Electric Corporation manufactured an electric rice cooker, a pot incorporating a heating coil inside. Featuring no automation, this was simply a pot that used a heating coil instead of firewood or gas. The device was inconvenient, requiring attention from the time it was switched until the rice was done, and sold poorly. Rather than being remembered as the forerunner of modern rice cookers, the device was relegated to the status of a footnote in the history of electric appliances. In 1952, Matsushita Electric launched a Mitsubishi-type rice cooker, which was also poorly received. Sony's offering (an electronic rice tube) fared likewise. Around July 1951, based on its conviction that electrical appliances would one day become a part of daily life in Japan, Toshiba tackled the challenge of creating a successful electric rice cooker, a product area where leading manufacturers Mitsubishi and Matsushita had failed. The project was led by Shogo Yamada, development manager of the electric appliance division. On December 10, 1956, about five and a half years after the project began, 700 rice cookers were placed on the market. Familiar with the history of poor sales, distributors were reluctant to sell them. In response, Toshiba created a new distribution network (Note 1). The rice cooker began to sell ? like rice cakes, as it were! Soon, Toshiba was producing 200,000 a month. Four years after their introduction, rice cookers were to be found in half the homes in Japan. In 1970, total annual output had reached 12,350,000 cookers. Cooking rice, the staple food of the Japanese, was part of the unavoidable housework of housewives, in addition to cleaning and washing. It took certain skill to make good rice. The advent of the electric rice cooker with a timer switch not only cooked rice automatically by a desired time, it reduced the time required for basic housework and changed the lifestyle of the Japanese people. Toshiba's first electric rice cooker represented the advent of a revolution in Japanese food culture. The award-winning design remained unchanged for nine years. Previously, very few engineers had considered the nature of the rice itself being cooked or the process of the cooking, regarding rice cookers as simple devices that were turned on or off. Uncooked starch of which the crystal structure is confirmed by X-ray crystallography is called a starch. When this starch is heated and the crystal structure is no longer visible, it is then called a starch or "gelatinized starch". The purpose of processing starches is to transform a starch to a starch. If heated at 98 degrees C for 20 minutes, all the rice in the cooker is nicely cooked and transformed into a starch. The result of a consumer survey indicated that the heat source does not necessarily require adjustment, as traditionally believed. Better results were obtained by cooking over a constant high flame. The Toshiba project team performed a test, during the course of which they discovered that the only necessary factor was heating the rice for 20 minutes after it came to a boil. This finding convinced the project team that an improved rice cooker was close to being developed. They researchers found that potatoes begin to transform into a starch at about 47 degrees C, and rice at 57.8 degrees C, and they performed additional experiments. They found that, at 57.8 degrees C, it took 15 to 16 hours to transform 1.5 kg of rice into a starch. They repeated the tests, gradually increasing the temperature, discovering that if rice is transformed into a starch at 73 degrees C, it remains converted. This is now used as the principle of the insulated rice cooker. They then continued to heat the rice at 98 degrees C for 20 minutes, which effected a permanent transformation of the rice into a starch. The results were verified via electron microscope, just introduced at that time. Theory dictated that cooking rice for 20 some minutes on a timer would result in well-cooked rice. Practice didn't bear this out. When cooked with a prototype cooker, rice was half-cooked or scorched. This was because the required boiling actually depended on several variables, including the external temperature of the cooker, the heating value, and the amount of rice or water. The problem then came how to detect the when the rice actually begins to boil, and how to turn off the switch exactly 20 minutes thereafter. The solution was indirect cooking using a double pot, based on trial and error. A cup of water was poured into the outer pot; this amount would evaporate in 20 minutes. When the water evaporated, the temperature of the pot exceeded 100 degrees C. This was detected by a bimetallic thermostat and the switch was turned off. Water evaporation was used as the timer. The idea was simple and elegant, and uniquely Japanese. The successful rice cooker was based on countless trial and error efforts, which involved enlisting even the president of an ice manufacturer, Koshin-sha, and his wife, who performed experiments in their own warehouse or in their garden in the dead of winter. Note 1) The issue of surplus power production posed a significant challenge to electric power companies at the time. Toshiba asked the companies to serve as distributors of the automatic electric rice cooker, a request with which the companies were happy to comply. Employees visited various homes, armed with rice cookers. Thanks to such efforts, sales of rice cookers began to soar. (The power surplus stemmed from the widespread replacement of carbon-filament light bulbs with significantly more efficient tungsten bulbs, reducing electricity demand to levels that resulted in the suspension of operations at half of the country's power plants.) |
|
|||||
TOSHIBA SCIENCE MUSEUM
1, Komukai Toshiba-Cho, Saiwai-Ku, Kawasaki 212-8582, Japan TEL : 81-44-549-2200 FAX : 81-44-520-1500
