Rice cooker
Encyclopedia
A rice cooker or rice steamer is a container or kitchen appliance dedicated to cooking
Cooking
Cooking is the process of preparing food by use of heat. Cooking techniques and ingredients vary widely across the world, reflecting unique environmental, economic, and cultural traditions. Cooks themselves also vary widely in skill and training...

 rice
Rice
Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...

. Rice can also be cooked in general-purpose saucepans.

Overview

Rice cookers may be divided into a variety of rice cooking sauce pans or pots (e.g. risotto
Risotto
Risotto is a class of Italian dishes of rice cooked in broth to a creamy consistency. The broth may be meat-, fish-, or vegetable-based; many kinds include Parmesan cheese, butter, and onion...

 pan, paella
Paella
Paella is a Valencian rice dish that originated in its modern form in the mid-19th century near lake Albufera, a lagoon in Valencia, on the east coast of Spain. Many non-Spaniards view paella as Spain's national dish, but most Spaniards consider it to be a regional Valencian dish...

 pan, porridge
Porridge
Porridge is a dish made by boiling oats or other cereal meals in water, milk, or both. It is usually served hot in a bowl or dish...

 pot), rice steamers (e.g. 釜 (zhēng lóng), ceramic or plastic containers for microwave oven
Microwave oven
A microwave oven is a kitchen appliance that heats food by dielectric heating, using microwave radiation to heat polarized molecules within the food...

, and gas and electrical appliances. Most dedicated home rice cookers are of electric type. In commercial or industrial use, there are many varieties, such as large gas or electric rice cookers, a large-scale rice cooker that is called "rice boiler", and fully automatic versions which handle the whole process of rice cooking from washing rice to the end of the cooking cycle. Dedicated rice cookers date from long ago in human history. A ceramic rice steamer dated to 1250 BC is on display in the British Museum.

Cooking rice has traditionally been a process which required attention to ensure the rice was cooked properly. Electric rice cookers automate the process by mechanically or electronically controlling heat and timing, thus freeing up a heating element on the cooking range that had to be occupied, otherwise for rice cooking. Although the rice cooker does not necessarily speed up the cooking process, with an electric rice cooker the cook's involvement in cooking rice is reduced to simply measuring the rice, preparing the rice properly and using the correct amount of water. Once the rice cooker is set to cook, the rice will be cooked with no further attention. Many modern cookers have heat insulating casing and a warming mechanism. When the rice is determined to be fully cooked, the unit will automatically switch to the "keep warm" cycle, thus preventing the rice from being overcooked and keeping the rice warm until it is ready to be served. They can also be used to keep cold solids cold because they are made to sustain the same heat that is inside them.

It takes about 30 minutes to 1 hour for most of electric rice cookers to complete cooking. Some advanced models can back-calculate the cooking start time from given finish time. The time required for cooking rice depends on amount of rice, power of the heating elements, and atmospheric pressure, thus it is not constant. Pressure-cooker models are not influenced by atmospheric pressure. The special features distinguish high-end models from lower-cost, simpler models.

Some types of rice dishes require special ways of preparation and are not suited to the mode of cooking represented by electric/gas rice cookers. These recipes include risotto
Risotto
Risotto is a class of Italian dishes of rice cooked in broth to a creamy consistency. The broth may be meat-, fish-, or vegetable-based; many kinds include Parmesan cheese, butter, and onion...

, paella
Paella
Paella is a Valencian rice dish that originated in its modern form in the mid-19th century near lake Albufera, a lagoon in Valencia, on the east coast of Spain. Many non-Spaniards view paella as Spain's national dish, but most Spaniards consider it to be a regional Valencian dish...

, and stuffed peppers
Stuffed peppers
Stuffed peppers is a dish which exists in different names and forms around the world.- India :Stuffed Peppers is one of several stuffed vegetable dishes in Indian cuisine...

 (Capsicums).

In the early days of electric home rice cookers in Japan, the products were manufactured, marketed and purchased only within Japan. With the trend of Japanese cuisine spreading abroad, they were exported to Western countries. They were also exported to rice-consuming Asian countries as the average family income has improved and reduced manual labor is desired. Many products are now manufactured in China, Korea, and Malaysia. Even some rice cookers intended only for Japanese domestic market are now manufactured outside Japan.

Traditional rice cooking methods and utensils

Rice is cooked by heating in boiling water or steam, or a combination (boiling until water evaporates, then continuing in steam generated by continued heating). It absorbs a great deal of water in the process, expanding its volume and using up the cooking water. The moisture and heat gelate
Starch gelatinization
Starch gelatinization is a process that breaks down the intermolecular bonds of starch molecules in the presence of water and heat, allowing the hydrogen bonding sites to engage more water. This irreversibly dissolves the starch granule...

 and soften the starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...

 granules
Granule (cell biology)
In cell biology, a granule is a small particle. It can be any structure barely visible by light microscopy. The term is most often used to describe a secretory vesicle.-Leukocytes:...

 in the rice. The cooking time for raw rice (not parboiled beforehand) ranges from about 15 minutes up, depending upon type and freshness of rice, method, and desired result (from separate grains to disintegrated porridge).
  • Boiling: long grain rice e.g. basmati rice, Thai jasmine rice
    Jasmine rice
    Jasmine rice , sometimes known as Thai fragrant rice, is a long-grain variety of rice that has a nutty aroma and a subtle pandan-like flavor caused by 2-acetyl-1-pyrroline.Jasmine rice is originally from Thailand...

    : Boiling pan
  • steaming
    Steaming
    Steaming is a method of cooking using steam. Steaming is considered a healthy cooking technique and capable of cooking almost all kinds of food.-Method:...

    : long grain rice, ibid: Steamer e.g. Mushiki
    Mushiki
    Mushiki or seiro are two different types of Japanese steamers.Mushiki are round steamers made from bamboo like those used in Chinese cuisine. They can be stacked on top of each other so that the steam can cook many different servings simultaneously...

     (zhēng lóng)
  • absorption method with boiling: Japanese rice
    Japanese rice
    Japanese rice, or japonica, is a short-grain variety of rice which is characterized by its unique stickiness and texture. It also comes in a variety called mochigome which is used for making mochi...

     e.g Calrose rice: Asian traditional rice cooker on hearth, i.e. 釜
  • absorption method with oven: e.g. Paella
    Paella
    Paella is a Valencian rice dish that originated in its modern form in the mid-19th century near lake Albufera, a lagoon in Valencia, on the east coast of Spain. Many non-Spaniards view paella as Spain's national dish, but most Spaniards consider it to be a regional Valencian dish...

    , pilaf
    Pilaf
    Pilaf is a dish in which rice is cooked in a seasoned broth . In some cases, the rice may also attain its brown color by being stirred with bits of cooked onion, as well as a large mix of spices...

    : Paella pan
  • absorption method with stirring: e.g. Risotto
    Risotto
    Risotto is a class of Italian dishes of rice cooked in broth to a creamy consistency. The broth may be meat-, fish-, or vegetable-based; many kinds include Parmesan cheese, butter, and onion...

    : Risotto pan
  • slow cooking: e.g. porridge
    Porridge
    Porridge is a dish made by boiling oats or other cereal meals in water, milk, or both. It is usually served hot in a bowl or dish...

    : Porridge pot

Features and specifications

For the modern home rice cookers, the smallest single-person model cooks 1 rice cup (180 ml) whereas the largest cooks 10 rice cups (1.8 liter). The prices vary greatly, depending on the capacity, features, materials used, the countries of origin. The typical lower price models use electric heaters to heat the inner cooking bowl controlled by built-in microprocessors, whereas the high-end models feature various ideas of improved and better cooking methods.

These inventions include, e.g. microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...

-controlled cooking cycles, employing pressure cooking
Pressure cooking
Pressure cooking is a method of cooking in a sealed vessel that does not permit air or liquids to escape below a preset pressure. Because the boiling point of water increases as the pressure increases, the pressure built up inside the cooker allows the liquid in the pot to rise to a higher...

, utilizing induction heating
Induction heating
Induction heating is the process of heating an electrically conducting object by electromagnetic induction, where eddy currents are generated within the metal and resistance leads to Joule heating of the metal...

 (IH) that can generate heat directly within the inner cooking bowl itself (all the IH type models are microprocessor-controlled), employing varying pressure control mechanism named "dual-pressure" method that creates repeated pressure/release cycles during the cooking, using various materials (e.g. copper, pure carbon, ceramic, diamond powder coating) for the inner cooking bowl because of their higher heat conductivity, utilizing more than one induction heating element, or employing a mechanism to collect and return the boiled over liquid to the inner rice bowl.The rice cookers which are very large to store tons of rice are used in places like Guruvayur.

The pressure-cooking models can raise the water's boiling point higher, e.g. from 100 °C at 1.0 atm
Atmosphere (unit)
The standard atmosphere is an international reference pressure defined as 101325 Pa and formerly used as unit of pressure. For practical purposes it has been replaced by the bar which is 105 Pa...

 up to about 110 °C at 1.4 atm, and are generally believed to produce a better result. They are also suitable for cooking brown rice
Brown rice
Brown rice is unmilled or partly milled rice, a kind of whole, natural grain. It has a mild nutty flavor, is chewier and more nutritious than white rice, but goes rancid more quickly because the germ—which is removed to make white rice—contains fats that can spoil...

, which is richer in dietary fiber, more digestible. The pressure cooking models can also be used in high altitude areas.

Additional features

Stay-warm (keep-warm) feature: Majority of modern rice cookers are equipped with this function. (Some gas cookers also have electric stay-warm mechanism).

Many models feature an ability to cook sticky rice or porridge as an added value. Most can be used as steamers. Some can be used as slow cooking pots. Some other models can bake bread or in some cases have an added function to maintain temperatures suitable for fermentation of bread dough or yogurt. Likewise, depending on the model, these days it is common to see many added functions other than cooking rice.

In the 2000s in Japan, it was popular to cook soups, stews or sponge cakes in electric rice cookers. Books have been published for these recipes.

If the rice cooker is not suited for such uses, there is a chance that it may damage the appliance. In particular, it is quite possible that the Teflon coating get scarred by the rough bottom of ceramic wares placed inside the inner cooking bowl. In some cases, apparently there were troubles of causing rice to burn and stick to the bowl, damaging the packing parts, odors becoming persistent and tainting the rice cooked afterward. If such cooking was outside indicated usage of the appliance, it, of course, violates the warranty. In some countries, electric rice cookers including Japanese models are regarded as automated universal electric cooking pots and their use in preparation of variety of food is rather standard.

History

In 1937, the Japanese Imperial Army sanctioned an automobile-kitchen equipped with a primitive rice cooker. The rice cooker was a rectangular wooden box with two electrodes attached to opposite ends. To cook the rice, the box was filled with washed rice and water, and then a current was applied. This caused the water to boil. When the rice was cooked, the reduction of the water caused an increase in resistance and reduced the heat, then it automatically became a stay-warm state. This method, however, was not suitable for different water qualities or degrees of rice washing and as such varied the amount of heat produced and the end results. It also presented a large risk of electrocution, thus it was not suitable for home cooking.

In 1945, the Mitsubishi Electric
Mitsubishi Electric
is a multinational electronics and information technology company headquartered in Tokyo, Japan. It is one of the core companies of the Mitsubishi Group....

 Corporation of Japan was the first company to produce a commercially available electric rice cooker. The Mitsubishi product was an aluminum pot with a heating coil inside. It had no automatic turn-off facility, and it required constant monitoring during cooking.

In the early development phase, electric home rice cookers used the simple concept of simply heating the rice to cook and turning off the heater when the temperature rose to a certain point. This method, however, is influenced too greatly with seasonal changes in room temperature and often produced under-cooked rice. It was an imperfect idea. Many makers continued to experience failures in their ongoing trial-error approaches. At this stage, there was even a trial model which embedded heating element in traditional wooden rice container.

The first practical electric rice cooker was invited by Yoshitada Minami, who had an association with Toshiba
Toshiba
is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...

 Electric Corporation. It became possible to cook rice practically by employing the triple-chamber rice cooker (that provided heat insulation by air layers).

In December 1956, the Toshiba
Toshiba
is a multinational electronics and electrical equipment corporation headquartered in Tokyo, Japan. It is a diversified manufacturer and marketer of electrical products, spanning information & communications equipment and systems, Internet-based solutions and services, electronic components and...

 Corporation placed the first commercially successful automated electric rice cookers on the market. It used a double-chamber indirect rice cooking method. Rice was placed into the rice pot, and water into a surrounding container. When the water in the outer pot boiled off, the temperature of the pot rose rapidly. A bimetallic thermostat then activated, and automatically turned off the cooker to prevent burning of the cooked rice. Soon, Toshiba was producing 200,000 rice cookers per month for the Japanese market. Four years later, rice cookers could be found in half of Japanese homes.

The double-chamber indirect cooking model took more time to complete cooking and also consumed more electricity. This model was gradually phased out since the 1960s, but there are some companies, such as Tatung
Tatung Company
Tatung Company , also known as Tatung, is a multinational corporation established in 1918 and headquartered in Zhongshan, Taipei, Taiwan. Tatung also maintains a regional headquarters in Long Beach, California for the U.S...

, that still manufacture them. Today, electric rice cookers utilize an insulated outer container and an inner removable bowl, often coated with a non-stick surface, and stamped with water-level graduations marked in cups
Cup (unit)
The cup is a customary unit of measurement for volume, used in cooking to measure liquids and bulk foods such as granulated sugar...

 of rice used. The rice cup measure is normally based on the traditional Japanese measurement system 1 , which has its origin in China (
Gê are the people who spoke Ge languages of the northern South American Caribbean coast and Brazil. In Brazil the Gê were found in Rio de Janeiro, Minas Gerais, Bahia, Piaui, Mato Grosso, Goias, Tocantins, Maranhão, and as far south as Paraguay....

合). 1 is 180 ml, approximately 25% smaller than the American measuring cup of 8 (US) fluid ounces / 240 ml. 1 cup is regarded to produce enough cooked rice enough for a meal for one person.

Initial models did not have a keep-warm feature and the cooked rice cooled down too quickly, thus it was often necessary to move the cooked rice to heat insulated serving containers. In 1965, Zojirushi Thermos company started selling electric rice cookers with a stay-warm function using a semi-conductor heat regulator. The product sold 2,000,000 units per year. The other makers soon followed suit. The stay-warm function can typically keep rice warm for up to 24 hours at a temperature high enough to suppress growth of Bacillus cereus
Bacillus cereus
Bacillus cereus is an endemic, soil-dwelling, Gram-positive, rod-shaped, beta hemolytic bacterium. Some strains are harmful to humans and cause foodborne illness, while other strains can be beneficial as probiotics for animals...

, a cause of food poisoning. Another notable improvement was the use of electric timers.

In simple models, a mechanical thermostat is used to turn off the cooker when the rice is ready. Since the 1980s higher-end electric rice cookers have used microprocessors to control the cooking process, often incorporating a memory and electronic timer
Timer
A timer is a specialized type of clock. A timer can be used to control the sequence of an event or process. Whereas a stopwatch counts upwards from zero for measuring elapsed time, a timer counts down from a specified time interval, like an hourglass.Timers can be mechanical, electromechanical,...

 that can be used to set the desired "ready time". Since the 1990s many models allow users to select desired cooking results for rice (e.g. soft, medium, firm, etc.), different types of rice, or some other ingredients than rice. Some models can be used as steamers.

In the late 1980s some higher-end electric rice cookers started using induction heating
Induction heating
Induction heating is the process of heating an electrically conducting object by electromagnetic induction, where eddy currents are generated within the metal and resistance leads to Joule heating of the metal...

. This type aims to produce tastier cooked rice by controlling the heating process more precisely. Some other pressure-cooking models use 1.2 atm to 1.7 atm (not over 1.4 atm for home appliances) to raise the cooking temperature over 100 °C. Expensive models often provide steam-heating function.

In the 1990s China started-mass producing economical electrical rice cookers with limited functions and exporting them to many countries. Japanese makers have been attempting to compete by seeking a niche in models with added values by increasing features of products.

In the 2000s more deluxe models appeared on the market and attracted much attention. These models are characterized with non-metallic materials for inner cooking bowls to employ thermal far-infrared radiation in order to improve the taste of cooked rice. In 2006 Mitsubishi Electric
Mitsubishi Electric
is a multinational electronics and information technology company headquartered in Tokyo, Japan. It is one of the core companies of the Mitsubishi Group....

 produced an expensive cooker which used an inner cooking bowl called "honsumigama" 本炭釜 made of hand-carved pure carbon, with a better heat-generating profile with induction cooking. Despite the high price (¥115,500, about US$1,400 at the time), it sold 10,000 units within 6 months after it was introduced. It was a huge success and it set the trend of extremely high-end models in the market. There is also a product which uses pottery e.g. Arita-yaki for the inner cooking bowl. There have been pottery-based electric cooking appliances in China since the 1980s, and in recent years rice cookers have been also produced. Some other materials used for luxurious rice bowls are pure copper, ceramic-iron layers, and diamond coating. These rice cooker makers research on what the best cooked rice means (in taste and texture) and attempt to realize "the best cooked rice" in electric rice cookers by using various inventions. Most regard rice cooked either in a traditional rice cooker used in hearth or in a gas pressure cooker as references, and attempt to achieve the same or to exceed.

Restaurants that serve a lot of rice, particularly those specializing in Asian cuisine
Asian cuisine
Asian cuisine styles can be broken down into several tiny regional styles that have roots in the peoples and cultures of those regions. The major types can be roughly defined as East Asian with its origins in Imperial China and now encompassing modern Japan and the Korean peninsula; Southeast Asian...

, often use industrial size rice cookers (often they are gas pressure cookers, but there are electric models) that quickly and cheaply produce large quantities of cooked rice. A rice cooker is a standard appliance in kitchen
Kitchen
A kitchen is a room or part of a room used for cooking and food preparation.In the West, a modern residential kitchen is typically equipped with a stove, a sink with hot and cold running water, a refrigerator and kitchen cabinets arranged according to a modular design. Many households have a...

s in many Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

n countries and households; a recent survey showed that over 95% of Japanese kitchen
Japanese kitchen
Daidokoro is the place where food is prepared in a Japanese house. Until the Meiji era, a kitchen was also called kamado and there are many sayings in the Japanese language that involve kamado as it was considered the symbol of a house. The term could even be used to mean "family" or "household"...

s feature such a device.

Basic principle of operation (basic rice cooker models)

The bowl in the rice cooker is usually removable; beneath it there is a heater and thermostat
Thermostat
A thermostat is the component of a control system which regulates the temperature of a system so that the system's temperature is maintained near a desired setpoint temperature. The thermostat does this by switching heating or cooling devices on or off, or regulating the flow of a heat transfer...

. A spring pushes the thermostat against the bottom of the bowl for good thermal contact. During cooking the rice/water mixture is heated at full power. The water reaches a temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

 of 100 °C (212 °F); it cannot get hotter than its boiling
Boiling
Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding environmental pressure. While below the boiling point a liquid...

 point. By the end of cooking there will be no free water left; most will have been absorbed by the rice, and some boiled off. As heating continues, the temperature can now rise above boiling point; this makes the thermostat trip. Some cookers switch to low-power "warming" mode, keeping the rice at a safe temperature of approximately 65 °C (150 °F); simpler models switch off.

Cooking rice with an electric rice cooker

The rice is measured and added to the inner bowl or washed in a separate bowl (it is not recommended to wash rice in the inner bowl itself) in order to remove loosened starch and residual bran. Strainers are often used in the washing and draining process. For better texture and taste, some types of rice, e.g. Japanese rice or Calrose rice which is suited for absorption method, require pre-cooking water absorption. The water absorption step typically involves letting the rice stand for at least 5 min after draining water from the washing step and soaking the rice in the measured water for at least 15 min (or some claim it to be 1 hour) before cooking. The water draining step is believed to make it the water measurement more accurate, if the water is measured and added after the initial water absorption that takes place in the washing step. Some people prefer to achieve the water absorption by simply leaving the rice soaking in the rice cooker overnight before starting cooking in the morning. Some other types of rice, e.g. long-grain rice or scented rice such as jasmine rice
Jasmine rice
Jasmine rice , sometimes known as Thai fragrant rice, is a long-grain variety of rice that has a nutty aroma and a subtle pandan-like flavor caused by 2-acetyl-1-pyrroline.Jasmine rice is originally from Thailand...

, do not require washing or the water absorption step. The water for cooking is added to the inner bowl by using measuring cups or simply filling up to the appropriate graduated mark in the inner bowl. Although cold water is normally added, boiling water is used for cooking sushi rice.

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
Brown rice
Brown rice is unmilled or partly milled rice, a kind of whole, natural grain. It has a mild nutty flavor, is chewier and more nutritious than white rice, but goes rancid more quickly because the germ—which is removed to make white rice—contains fats that can spoil...

 (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. Most models give a countdown in minutes to the "ready time," or beep when done. After cooking cycle is completed, it is recommended that the rice is to "rest" for 5 minute for post-absorption and then to be stirred to prevent the grains from clinging to each other too hard. Some rice, e.g. long-grain or scented rice, do not seem to require this post-absorption step.

Some higher-end models automatically time the soaking (pre-cooking water absorption) and the resting periods, therefore, there is no need to manually manage the water absorption or time these steps.

Rice types and rice cookers

There are 3 different types of Asian rice: Oryza sativa
Oryza sativa
Oryza sativa, commonly known as Asian rice, is the plant species most commonly referred to in English as rice. Oryza sativa is the cereal with the smallest genome, consisting of just 430Mb across 12 chromosomes...

subsp. indica i.e. Indian rice (long grain rice e.g. basmati
Basmati
Basmati is a variety of long grain rice grown in India, Bangladesh and Pakistan, notable for its fragrance and delicate, nuanced flavour. Its name means "the fragrant one" in Sanskrit, but it can also mean "the soft rice," and the word coincidentally means "my smile" in Arabic...

 rice and Thai jasmine rice), O. sativa subsp. javanica i.e. Java rice (large grain rice) and O. sativa subsp. japonica i.e. Japanese rice
Japanese rice
Japanese rice, or japonica, is a short-grain variety of rice which is characterized by its unique stickiness and texture. It also comes in a variety called mochigome which is used for making mochi...

 (medium grain rice e.g. Calrose rice, short grain rice e.g. most Japanese rice and risotto
Risotto
Risotto is a class of Italian dishes of rice cooked in broth to a creamy consistency. The broth may be meat-, fish-, or vegetable-based; many kinds include Parmesan cheese, butter, and onion...

 rice). In addition, Oryza glaberrima is known as African rice
African rice
Oryza glaberrima, commonly known as African rice, is a domesticated rice species. African rice is believed to have been domesticated 2,000-3,000 years ago in the inland delta of the Upper Niger river, in what is now Mali...

.

Each rice cooker model may be optimized to cook a certain type of rice best. For example, most Japanese rice cookers are optimized for cooking Japanese rice and may not be the best for other types of rice. The typical method of cooking long grain rice is boil-and-strain and/or steaming method. The absorption method used in Japanese rice cookers will produce slightly different texture and taste, usually stickier rice.

Japanese rice cookers used overseas

Since the 1980s, electric rice cookers were manufactured in China and Korea, who focused on simple feature models because of the market trend which regarded the price competition to be more important than rich features.

Some visitors to Japan desired to buy Japanese domestic models as souvenirs, due to their ability to produce better tasting cooked rice and the multiple features. Since the Japanese domestic models use 100 volts only, they cannot be used in most other countries without adapters and power converters. In Akihabara
Akihabara
, also known as , is an area of Tokyo, Japan. It is located less than five minutes by rail from Tokyo Station. Its name is frequently shortened to in Japan...

 Electric Town, various models that are modified to be able to operate under 110 V/220 V-240 V are sold in boxes that are labeled with English. A few rice cooker makers (see below) produce export models for use abroad.

Online vendors sell mid-range to low-end models outside Japan. So far, however, it seems that the high-end models are available only to the Japanese domestic market.

Rice cooker techniques

Rice cookers are typically used for the preparation of plain or lightly seasoned rice. Some also have settings for rice porridge, called okayu in Japanese, congee
Congee
Congee is a type of rice porridge popular in many Asian countries. It can be eaten alone or served with a side dish. Names for congee are as varied as the style of its preparation...

in Chinese. More elaborate recipes are possible using a rice cooker, and there are cookbooks devoted entirely to dishes prepared using a rice cooker. Dishes that can be made in a rice cooker include beef stew. By simply adding ingredients and setting it to "warm", a rice cooker would cook that at about 65°C (150°F). In a few hours, the stew is fully cooked and ready to eat.

Some rice cookers are designed to accommodate a basket to steam vegetables, dumplings, buns, and so on in the steam coming off the rice.

Production

There were approximately 85 million rice cookers made in 2005. Most of the rice cookers were made in China, Korea and Japan, with 70% of the production in China. Most of Chinese production was from Zhanjiang
Zhanjiang
Zhanjiang , formerly known as Tsamkong, Tsankiang, Fort-Bayard, and Kwang-Chou-Wan, is a prefecture-level city at the southwestern end of Guangdong province of Southern China, facing the island of Hainan to the south....

 City and Lianjiang City in Guangdong Province.

Microwave rice cookers

A microwave rice cooker is a microwavable container designed specifically for cooking rice.
Some container consists of three parts: an outer bowl, a fitted lid with steam vents, and an inner bowl with a finely perforated base. Some others have only one container and the double-layered lid fitted with a steam vent.

A measured amount of dry rice is placed within the bowl. For long-grain rice or scented rice (e.g. basmati rice, Thai
Thai people
The Thai people, or Siamese, are the main ethnic group of Thailand and are part of the larger Tai ethnolinguistic peoples found in Thailand and adjacent countries in Southeast Asia as well as southern China. Their language is the Thai language, which is classified as part of the Kradai family of...

 jasmine rice
Jasmine rice
Jasmine rice , sometimes known as Thai fragrant rice, is a long-grain variety of rice that has a nutty aroma and a subtle pandan-like flavor caused by 2-acetyl-1-pyrroline.Jasmine rice is originally from Thailand...

), neither washing or soaking is usually necessary unless contaminating dirt is suspected. For Japanese rice
Japanese rice
Japanese rice, or japonica, is a short-grain variety of rice which is characterized by its unique stickiness and texture. It also comes in a variety called mochigome which is used for making mochi...

 (e.g. Calrose or medium/short grain rice), the rice is washed to remove surface starch powder and the trace of rice bran from the grains. For washing, a generous amount of water is added to the rice then the mixture is stirred a few times with a hand quickly. The water is then drained immediately while the lighter starch is still in the water, and the heavier rice grains settle at the bottom of the container. The washing process may need to be repeated about 3 times until the water draining out is clear of starch. The excessive washing, however, is believed to be detrimental, since it will remove too much water-soluble nutrients, e.g. vitamins.

With the 3 part model, the inner bowl is then placed within the outer bowl and a small amount of water is added, so that the rice is just about covered. The lid is then fitted and the cooker is microwaved at full power for between 8 and 15 minutes (depending on the rice type, power output of the appliance and personal texture preference). Cooking occurs with the water boiling away and steaming the grains. It is very important to follow the manufacturer's instructions regarding the length of time and amount of water added, otherwise the rice can burn. This method works well with long-grain rice that does not release much starch and is conventionally cooked with boil/strain or steam method.

The microwave rice cookers can also be used for cooking Japanese rice, or medium- or short grain rice, but the absorption method should be used. The rice is washed to remove starch well and allowed to stand to absorb water for at least 15 min before cooking. The water absorption step is essential, otherwise the cooking may result in cooked rice which is still too hard. The regular amount of water as the conventional cooking method can be used. The container is placed in the microwave and it is brought up to the boil at high power. Then, it can be cooked at low or low-medium power until all the water is evaporated (about 20 min - 30 min, depending on the rice type) and not much steam is coming out. The container is then left to stand for 5 min before the rice is stirred for serving.

Gas rice cookers

Most gas rice cookers are of pressure cooker type and have larger capacity than home rice cookers (1 to 2 litres). They are more commonly used for commercial and industrial purposes. Different from conventional gas pressure cookers, they are designed for easier rice-serving and easier cleaning. In general, it is believed that gas pressure cookers produce better cooked rice than conventional electric rice cookers that do not employ pressure cooking. Some are equipped with a heat insulating outer layer and electric keep-warm feature.

See also

Rice Cookers Recipes and Instruction Manuals

Further reading

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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