The Humble Wok

Most woks range from 30 cm to 2 metres or more in diameter with a rounded bottom. Woks of 36 cm (14 inches) (suitable for a family of 3 or 4) are the most common, but home woks can be found as small as 20 cm (8") and as large as 91 cm (36"). Smaller woks are typically used for quick cooking techniques at high heat such as stir frying. Large woks over a meter wide are mainly used by restaurants or community kitchens for cooking rice.

They are usually made from carbon steel and cast iron. 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.

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 "hot spots" due to uneven heat distribution. 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. The real purpose of hand hammering is to create small ridges or dimples along the sides of the wok. These ridges are used in the frying technique of the chef.

Two types of cast iron woks can be found in the market. Chinese cast iron woks are thin (~3 mm) and weigh about the same as a carbon steel wok of similar size, while western cast iron woks tend to be thick (~9 mm), 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. 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 difficult for smaller chefs.

Non sticksteel woks are common in the western market. These are non popular with professionals. 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 perform extremely well but are often quite expensive, quite heavy and usually cook no better than carbon steel or cast iron woks.

The main advantage of the 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.

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. As such large food items can be shallow fried, while finely chopped ingredients like garlic or ginger can be essentially deep-fried in both cases with very small amount of cooking oil.