Rice cooker
From Wikipedia, the free encyclopedia
A rice cooker or rice steamer is a self-contained electrical appliance, used primarily for cooking rice. There are also microwave, gas, and open flame variants.
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[edit] Description
The preparation of rice has traditionally been a cooking process which requires attention to ensure the rice is cooked properly. Rice cookers simplify the process by automatically controlling the heat and timing, while at the same time freeing up a heating element on the range. Although the rice cooker does not necessarily speed up the cooking process, the cook's involvement in cooking rice with a rice cooker is reduced to simply using the correct amount of water. Once the rice cooker is set to cook, the rice will be cooked with no further attention.
Typically, a rice cooker contains an insulated outer container containing a heating element, into which is fitted a non-stick or teflon-coated inner removable bowl, which often has graduations marked in cups of rice (white). Whereas less expensive and older models use simple electronics and mechanical and thermal sensors, high-end rice cookers use microprocessors with fuzzy logic to control the cooking process [1] and often incorporate a timer which can be used to set the desired "ready time". Many rice cookers can keep rice warm safely for up to 24 hours. This helps to avoid the dangers of food poisoning due to Bacillus cereus. New rice cookers normally include a small measuring cup, and a plastic paddle for serving the cooked rice. (The rice cup measure is normally 180 ml, approximately 25% smaller than the western measuring cup of approx 8 ounces / 250 ml.)
Restaurants that serve a lot of rice, particularly those specializing in Asian cuisine, often use industrial size rice cookers that quickly and cheaply produce large quantities of cooked rice. A rice cooker is a standard appliance in kitchens in many Asian countries and in many Asian households.
Small, basic rice cookers can be purchased in the US at discount retailers often for as low as $10-$15, and units with large capacity and different selectable electronically-controlled cooking cycles can cost over $100.
[edit] Basic principle of operation
The bowl in the rice cooker is usually removable, and beneath it lies a heater and a thermostat. These form the main components of the rice cooker. A spring pushes the thermostat against the bottom of the bowl, for good thermal contact to ensure accurate temperature measurement. During cooking the rice/water mixture is heated at full power. The temperature cannot go above the boiling point of water -- 100°C (212°F) -- as any heat put into the rice/water mixture at that point will only cause the water to boil. At the end of cooking some of the water will have been absorbed by the rice and the rest is boiled off. Once the heating continues past this point, the temperature exceeds the boiling point. The thermostat then trips, switching the rice cooker to low power "warming" mode, keeping the rice no cooler than approximately 65°C (150°F). Simple rice cookers, like the one below, may simply turn off at this point.
[edit] Cooking rice with a rice cooker
The rice is measured and added to the inner bowl. Cold water is measured and added or the bowl is simply filled up to the appropriate graduated mark in the inner bowl.
Different kinds of rice require different amounts of water. Usually, there are graduated marks for the right amount of water only for white rice, but sometimes there are separate scales for brown rice (as more water is required) or for cooking other food in the appliance.
Once the lid is closed and the cooking cycle has been activated, the rice cooker does the rest. Higher-end models give a countdown in minutes to the "ready time," and beep when done, whereas less expensive and older models simply click or ring a bell when done. Many people prefer to let the rice soak for awhile before cooking the rice; additionally, some like to allow the rice to "rest" for awhile after cooking before eating the rice. Higher-end models automatically time the soaking and resting periods.
[edit] Rice cooker techniques
Rice cookers are typically used for the preparation of plain or lightly seasoned rice, but more elaborate recipes are possible using a rice cooker, and there are cookbooks devoted entirely to dishes prepared using a rice cooker. One of the more unexpected dishes that can be made in a rice cooker is a beef stew. By simply adding ingredients and setting it to "warm", a rice cooker would cook that at about 65°C (150°F). In few hours, the stew is fully cooked and ready to eat.
Some rice cookers are designed to accommodate a basket above the rice. This basket is generally used to steam vegetables, holding them in the steam coming off the rice.
[edit] Miscellaneous
Each rice cooker typically comes with the cup that should be used for measuring rice for that particular cooker. The graduations on the bowl for adding water rely on using that particular measuring cup. The rice cooker cups can vary in size, but are typically 180 mL, which is the size of a traditional Japanese cup (gō). Note that this cup is not the same size as the customary 8 fl oz cup (of about 237 mL) which is used for cooking in the United States.