Wok

Stir frying (爆 bào) with a wok

A wok (in Cantonese; simplified Chinese: 镬; traditional Chinese: 鑊; Jyutping: wok6) is a versatile round-bottomed cooking vessel originating in China. It is used especially in East and Southeast Asia.

Woks are most often used for stir frying, but can also be used in other Chinese cooking techniques, such as in steaming, deep frying, braising, stewing, smoking, or making soup. They are commonly, almost exclusively, cooked with a long handled chahn (spatula) or hoak (ladle). The long extensions of these utensils allow the cook to work with the food without burning the hand.

Regional variants of the wok

Standard Chinese uses different words for wok, simplified Chinese: 锅; traditional Chinese: 鍋; literally "cooking pot" guō, simplified Chinese: 锅子; traditional Chinese: 鍋子 guōzi, or simplified Chinese: 炒菜锅; traditional Chinese: 炒菜鍋 chǎocàiguō. In Indonesia the wok is known as a penggorengan or wajan. In Malaysia it is called a kuali (small wok) or kawa (big wok). In the Philippines it is known as a kawali and also called a "wadjang". In Japan the wok is called a chukanabe (literally, "Chinese pot" or "中華鍋"). In India, two varieties of the wok exist: a more traditional chinese style wok with a wider diameter called the "cheena chatti" (literally, "Chinese pot" in Malayalam and Tamil), and a slightly deeper vessel with a narrower diameter and a similar shape, known as a karahi.

Characteristics

A wok sits next to a karahi on a Western-style stove. Note that the flatter-bottomed karahi (right) is sitting on an ordinary burner cover, while the round-bottomed wok is balanced in a wok-ring

The wok's most distinguishing feature is its shape. Classic woks have a rounded bottom. Hand-hammered woks are sometimes flipped inside out after being shaped, giving the wok a gentle flare to the edge that makes it easier to push food up onto the sides of the wok. Woks sold in western countries are sometimes found with flat bottoms — this makes them more similar to a deep frying pan. The flat bottom allows the wok to be used on an electric stove, where a rounded wok would not be able to fully contact the stove's heating element. A round bottom wok enables the traditional round spatula or ladle to pick all the food up at the bottom of the wok and toss it around easily; this is difficult with a flat bottom. With a gas hob, or traditional pit stove, the bottom of a round wok can get hotter than a flat wok and so is better for stir frying.

Most woks range from 300 to 2,000 mm (12 to 79 in) or more in diameter. Woks of 360 mm (14 in) (suitable for a family of 3 or 4) are the most common, but home woks can be found as small as 200 mm (8 in) and as large as 910 mm (36 in). Smaller woks are typically used for quick cooking techniques at high heat such as stir frying (Chinese: chǎo, 炒 or bao, 爆). Large woks over a meter wide are mainly used by restaurants or community kitchens for cooking rice or soup, or for boiling water.

Handles

A stick-handled flat-bottomed peking pan. While the surface looks like Teflon, it is actually well-seasoned carbon steel

The handles for woks come in two styles: loops and stick.^[1] Loop handles are the most common handle type for woks of all types and materials, and are usually made of bare metal. Cooks needing to hold the wok to toss the food in cooking do so by holding a loop handle with a thick towel (though some woks have spool-shaped wooden or plastic covers over the metal of the handle). Cooking with the tossing action in loop-handled woks requires a large amount of hand, arm and wrist strength. Loop handles typically come in pairs on the wok and are riveted, welded or extended from the wok basin.

Stick handles are long, made of steel, and are usually welded or riveted to the wok basin, or are an actual direct extension of the metal of the basin. The handle is sometimes covered or ended with a wooden or plastic hand grip, but it is not uncommon to find a bare metal grip. This handle facilitates the tossing action for cooks used to using western saute pans with similar style handles. These kinds of woks are often referred to as "Peking pans". Stick handles are normally not found on cast iron woks since the wok is either too heavy for the handle (thick cast iron wok), or the metal is too thin to handle the tensile stress exerted by the handle. Larger woks with stick type handles usually also have a loop on the other side to aid with handling the wok as well as to counter balance the stick type handle.

Materials

The most common materials used in making woks today are carbon steel and cast iron.^[1] Although the latter was the most common type used in the past, cooks tend to be divided on whether carbon steel or cast iron woks are superior.

Currently, carbon steel is the most widely used material. Steel woks are usually inexpensive, relatively light in weight, have quick heat conduction, and reasonable durability. However, carbon steel woks are more difficult to season and the carbonized season is easily removed in newer woks, both making food more prone to sticking to the wok. Carbon steel woks vary widely in price, style, and quality, which is roughly based on ply and forming technique. The lowest quality woks tend to be single ply and stamped straight from a piece of steel. These woks have a higher tendency to deform and misshape. Cooking with them is also more difficult and precarious since they often have a "hot spot". Higher quality woks are almost always "hand hammered" and made of two sheets of carbon steel which are formed into shape by "ring-forming" or hand forging.^[1]

Two types of cast iron woks can be found in the market. Chinese cast iron woks are thin (3 mm (0.12 in)) and weigh about the same as a carbon steel wok of similar size, while western cast iron woks tend to be thick (9 mm (0.35 in)), tend to be heavy, and require very long heating times. Cast iron woks are superior to carbon steel woks in heat retention and uniform heat distribution.^{[citation needed]} They also form a more stable carbonized layer of seasoning which makes it less prone to food sticking on the pan. However, both types of cast iron wok also have some disadvantages compared to carbon steel woks. Chinese-style cast iron woks, although quicker in heating and relatively light, are relatively fragile and are prone to shattering if dropped or mishandled. Western-type cast iron woks are slow-heating and slow-cooling, which makes temperature control more difficult. Furthermore, heavy western cast iron makes the tossing action required in stir-frying and bao difficult for smaller chefs.

Non-stick, steel woks coated with Teflon are common in the western market. These woks are easily scratched and cannot be used to cook in the high heat required for stir frying to excess of 230 °C (446 °F) since the Teflon coating will break down chemically at these temperatures. At 350 °C (662 °F) the burning coating produces vapours which, if inhaled, can cause flu-like symptoms (see Teflon flu). Xylan coated woks are slightly more robust, but still cannot be used for very high heat cooking. Less commonly found are clad woks, which sandwich a thick layer of aluminum or copper between two sheets of stainless steel. These woks are often quite expensive, quite heavy and usually cook no better than carbon steel or cast iron woks. Their biggest advantage lies in the durability and ease of maintenance of a stainless steel exterior and cooking surface. Many of these vessels are dishwasher safe.

Woks can also be made from aluminium. Although an excellent conductor of heat, aluminium does not retain heat (heat capacity) as well as cast iron or carbon steel. Although anodized aluminium alloys can stand up to constant use, plain aluminium woks are too soft and damage easily. Aluminium is mostly used for wok lids.

Cooking

The wok can be used in a large number of cooking methods. Before the introduction of western cookware it was often used for all cooking techniques including:^[1][2]

• Boiling: For boiling water, soups, or rice. In the latter case, guoba often forms
• Braising: Braised dishes are commonly made using woks and this is useful when one is reducing sauces.
• Deep frying: Usually accomplished with larger woks to reduce splashing, but for deep frying of less food or small food items, small woks are also used.
• Smoking: Food can be hot smoked by putting the smoking material in the bottom of the wok while food is placed on a rack above.
• Steaming: Done using a dedicated wok for boiling water in combination with steaming baskets
• Stewing: Woks are sometimes used for stewing though it is more common in Chinese cuisine to use either stoneware or porcelain for such purposes, especially when longer stewing times are required.

The most common use for a wok is stir-frying.

Wok hei

Wok hei (simplified Chinese: 镬气; traditional Chinese: 鑊氣; Jyutping: wok⁶ hei³; romanization based on Cantonese; and when literally translated into English, can be read as "Wok's air". The second character is qi in Mandarin, and thus wok hei is sometimes rendered as wok chi in Western cookbooks) is the flavour, tastes, and "essence" imparted by a hot wok on food during stir frying.^[1][3] It is particularly important for Chinese dishes requiring high heat for fragrance such as char kuay teow and beef chow fun.

To impart wok hei, the food must be cooked in a wok over a high flame while being stirred and tossed quickly. For this reason it requires cooking over an open flame rather than an electric stove. In practical terms, the flavour imparted by chemical compounds results from caramelization, Maillard reactions, and the partial combustion of oil that come from charring and searing of the food at very high heat in excess of 200 °C (392 °F). Aside from flavour, there is also the texture of the cooked items and smell involved that describes wok qi.

Wok stoves

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  Preparing food over a modern gas fired pit-type wok stove.

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  The two styles of traditional Chinese wok stoves (竈, 灶).

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  Outdoor wok stove with spent cylindrical charcoal briquettes inside

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  Natural gas burner head from a modern gas stove for woks

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  A carbon steel wok on a Chinese wok stove.

Traditional

A Han dynasty Chinese stove model with cooking pots showing the basic attributes that derived to modern wok stoves.

Woks were designed to be used over the traditional Chinese pit-style stove (simplified Chinese: 灶; traditional Chinese: 竃 or 竈; pinyin: zào) with the wok recessed into the stove top, where the heat is fully directed at the bottom of the wok. Round grate rings on the edge of the opening provide stability to the wok. There are two styles of traditional wok stoves. The more primitive style was used outdoors or in well ventilated areas since hot gasses from the firebox exhaust around the wok. The more advanced style, found in better-off households, has a chimney and may be used indoors.

Pit stoves originally burned wood or coal but are now more typically heated by natural gas with the burner recessed below the stovetop. In areas where natural gas is unavailable, LPG may be used instead. With the adoption of gas and its less objectionable combustion products, the chimney has been replaced by the vent hood.

This type of stove allows foods to be stir-fried at a very high heat, sometimes hot enough to deform the wok itself.^{[citation needed]} Professional chefs in Chinese restaurants often use pit stoves since they have the heating power to give food an alluring wok hei.

Gas

Traditionally-shaped woks can be used on some western-style (flat-topped) gas stoves by removing a burner cover and replacing it with a "wok ring," which provides stability and concentrates heat. Although not as ideal as "pit stoves", these allow woks to be used in a manner more suitable for their design and are good enough for most tasks required in home cooking.^[2]

Wok rings come in cylindrical and conical shapes. For greatest efficiency with the conical wok ring, position it with the wide side up. This allows the base of the wok to sit closer to the heat source.

Professional-style continuous grate stoves (where it's difficult or impossible to remove a single burner cover) have recently become more popular in high-end home stoves. Several manufacturers of such stoves now include a specially-designed wok ring as part of their standard or optional equipment.

Because of the high cost of these kitchen modifications, coupled with increased heat and smoke generated in the kitchen, more and more home chefs are using their wok outdoors on high-heat propane burners with curved wok support grates.^{[citation needed]} Many inexpensive propane burners are easily capable of 17.5 kW - 22 kW or more, easily surpassing most in-home gas stoves.

Electric

Woks, be they round or flat bottomed, do not generally work well for stir-frying or other quick cooking methods when used on an electric cooker. These stoves do not produce the large amounts of quick even heat required for stir-frying. However, it is possible to find round-shaped electric stove elements that will fit the curve of a wok, which allows the wok to be heated at its bottom along with part of its sides. A flat-bottomed wok may also work better on an electric stove.

Coupled with the lower heat retention of woks, meals stir-fried on electric stoves have a tendency to stew and boil when too much food is in the wok rather than "fry" as in traditional woks, thus not producing wok hei. However, a wok can benefit from the slow steady heating of electric stoves when used for slower cooking methods such as stewing, braising, and steaming, and immersion cooking techniques such as frying and boiling. Many Chinese cooks use Western style cast-iron pans for stir-frying on electric stoves, since they hold enough heat for the required sustained high temperatures.^[1]

A newer trend in woks is the electric wok, where no stove is needed. This type of wok is plugged into an electrical outlet and the heating element is in the wok. Like stove-mounted non-stick woks, these woks can also only be used at lower temperatures than traditional woks.

Induction

Induction cookers generate heat in induction-compatible cookware via direct magnetic stimulation of the pan material. While carbon steel and cast iron (the most common wok materials) are induction-compatible metals, induction cooking also requires close contact between the cooking vessel and the induction burner. This presents two problems when using a wok on an induction cooktop: traditionally shaped woks, which are round-bottomed, don't have enough contact with the cooking surface to generate notable heat; and the tossing technique, where the wok is lifted off the burner and agitated, will break contact and turn off the burner.

Flat-bottomed woks make sufficient contact to generate heat. Some cookware makers are now offering round-bottomed woks with a small flat spot to provide induction contact, with a specially-designed support ring; and some induction cooktops are now also available with a rounded burner that is able to make contact with the rounded bottom of a traditional wok. In both cases, the food will need to be stirred with a cooking utensil, instead of being tossed by lifting the wok itself.

Advantages

The main advantage of wok beyond its constructed material is its curved concave shape. The shape produces a small, hot area at the bottom which allows some of the food to be seared by intense heat while using relatively little fuel. The large sloped sides also make it easier for chefs to employ the tossing cooking technique on solid and thick liquid food with less spillage and a greater margin of safety. Curved sides also allows a person to cook without having to "chase the food around the pan" since bite-sized or finely chopped stir-fry ingredients usually tumble back to the center of the wok when agitated.^[1]

The curve also provides a larger usable cooking surface versus western-styled pots and pans, which typically have vertical edges. This allows large pieces of food seared at the bottom of the wok to be pushed up the gently sloped sides to continue cooking at a slower rate. While this occurs another ingredient for the same dish needing high heat is being cooked at the bottom. The pointed bottom also allows even small amounts of oil to pool.^[1] As such, large food items can be shallow fried, while finely chopped garlic, hot peppers, green onions, and ginger can be essentially deep-fried in both cases with very small amount of cooking oil.^[2]

See also

• Chinese cuisine
• Cantonese cuisine
• Karahi
• Qozon
• Wok racing

References

1. ^ ^{a b c d e f g h} Young, Grace (2004). The Breath of a Wok. Simon & Schuster. ISBN 0-7432-3827-3. 
2. ^ ^{a b c} Grigson, Jane (1985-01), World Atlas of Food, Bookthrift Company, ISBN 978-0671072117 
3. ^ Harpham, Zoė (2002). Essential Wok Cookbook. Murdoch Books. ISBN 978-1-74045-413-1. 

External links

• Wok Seasoning and Care from thaifoodandtravel.com
• Times Online – Ching He Huang – How to season a wok
• Chinese cooking skill using wok (video)