Stir frying

During the Tang dynasty (618–907) chao referred to roasting tea leaves. Stir frying became a popular method for cooking food only later, during the Ming dynasty (1368–1644).

The Chinese character "炒" is attested in inscriptions on bronze vessels from the Eastern Zhou period (771–256 BC), but not in the sense of stir frying.[5] Dry stirring was used in the Han dynasty (206 BC – 221 AD) to parch grain.[1] Although there are no surviving records of Han dynasty stir frying, archaeological evidence of woks and the tendency to slice food thinly indicate that the technique was likely used for cooking.[6]

The term chao appears for the first time in the sense of "stir frying" in the Qimin Yaoshu, a sixth-century agricultural manual, including in a recipe for scrambled eggs. In sources from the Tang dynasty (618–907), chao refers not to a cooking technique, but to a method for roasting tea leaves. It reappears as a cooking method in a dozen recipes from the Song dynasty (960–1279). The Song period is when the Chinese started to use vegetable oil for frying instead of animal fats. Until then, vegetable oil had been used chiefly in lamps.[1]

Historically, stir frying was not as important a technique as boiling or steaming, since the oil needed for stir frying was expensive. The technique became increasingly popular in the late Ming dynasty (1368–1644),[7] in part because the wood and charcoal used to fire stoves were becoming increasingly expensive near urban centers, and stir-frying could cook food quickly without wasting fuel.[8] "The increasingly commercial nature of city life" in the late Ming and Qing (1644–1912) periods also favored speedy methods.[1] But even as stir frying became an important method in Chinese cuisine, it did not replace other cooking techniques. For instance, "only five or six of over 100 recipes recorded in the sixteenth-century novel Jin Ping Mei are stir fry recipes and wok dishes accounted for only 16 percent of the recipes in the most famous eighteenth century recipe book, the Suiyuan shidan".[1]

By the late Qing, most Chinese kitchens were equipped with a wok range (chaozao 炒灶 or paotai zao 炮臺灶) convenient for stir-frying because it had a large hole in the middle to insert the bottom of a wok into the flames.[1]

Stir frying was brought to America by early Chinese immigrants, and has been used in non-Asian cuisine.[9]

The term "stir fry" as a translation for "chao" was coined in the 1945 book How To Cook and Eat in Chinese, by the linguist Yuen Ren Chao.[10] The book told the reader

Roughly speaking, ch'ao may be defined as a big-fire-shallow-fat-continual-stirring-quick-frying of cut-up material with wet seasoning. We shall call it 'stir-fry' or 'stir' for short. The nearest to this in western cooking is sauté. ... Because stir-frying has such critical timing and is done so quickly, it can be called 'blitz-cooking.'"[11]

In the West, stir fry spread from Chinese family and restaurant kitchens into general use. One popular cookbook noted that in the "health-conscious 1970s" suddenly it seemed that "everyone was buying a wok, and stir frying remained popular because it was quick." Many families had difficulty fitting a family dinner into their crowded schedules but found that stir fry could be prepared in as little as fifteen minutes.[12]

Ingredients are typically added in succession after cooking oil has been applied onto a hot pan. The ingredients that take longest to cook, like meat or tofu, are added before others, such as vinegar and soy sauce.

The chao (炒) technique is similar to the Western technique of sautéing.[14] There are regional variations in the amount and type of oil, the ratio of oil to other liquids, the combinations of ingredients, the use of hot peppers, and such, but the same basic procedure is followed in all parts of the country.

First the wok is heated to a high temperature, and just as or before it smokes, a small amount of cooking oil is added down the side of the wok (a traditional expression is "hot wok, cold oil"), followed by dry seasonings such as ginger, garlic, scallions, or shallots. The seasonings are tossed with a spatula until they are fragrant, then other ingredients are added, beginning with the ones taking the longest to cook, such as meat or tofu. When the meat and vegetables are nearly cooked, combinations of soy sauce, vinegar, wine, salt, or sugar may be added, along with thickeners such as cornstarch, water chestnut flour, or arrowroot.[15]

A single ingredient, especially a vegetable, may be stir-fried without the step of adding another ingredient, or two or more ingredients may be stir-fried to make a single dish. Although large leaf vegetables, such as cabbage or spinach, do not need to be cut into small pieces, for dishes which combine ingredients, they should all be cut to roughly the same size and shape.

Wok hei (simplified Chinese: 镬气; traditional Chinese: 鑊氣; Jyutping: wok⁶ hei³) romanization is based on the Cantonese Chinese pronunciation of the phrase; when literally translated into English, it can be translated as "wok thermal radiation"[16][17] or, metaphorically as the "breath of the wok". The phrase “breath of a wok” is a poetic translation Grace Young first coined in her cookbook, The Wisdom of the Chinese Kitchen.[18] In her book, The Breath of a Wok, Young further explores the ideas and concepts of wok hei.[19] An essay called “Wok Hay: The Breath of a Wok” explains how the definition of wok hei varies from cook to cook and how difficult it is to translate the term. Some define it as the “taste of the wok,” a “harmony of taste,” etc.: “I think of wok hay as the breath of a wok—when a wok breathes energy into a stir-fry, giving foods a unique concentrated flavor and aroma.”[20]

When read in Mandarin, the second character is transliterated as qi (ch'i according to its Wade-Giles romanization, so 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.[16][21] Out of the Eight Culinary Traditions of China, wok hei is encountered the most in Cantonese cuisine, whereas it may not even be an accepted underlying principle in some of the other Chinese cuisines.

To impart wok hei the traditional way, the food is cooked in a seasoned wok over a high flame while being stirred and tossed quickly.[16] The distinct taste of wok hei is partially imbued into the metal of the wok itself from previous cooking sessions and brought out again when cooking over high heat. 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).[17][22] Aside from flavour, wok hei also manifests itself in the texture and smell of the cooked items.

Bao stir frying involves high heat combined with continuous tossing. This keeps juices from flowing out of the ingredients and keeps the food crispy.

In the eighteenth and nineteenth centuries, the bao technique (Chinese: 爆; pinyin: bào; lit. 'pop, explosion') of stir-frying on a high flame was typical of cuisine from the northern Chinese province of Shandong.[1] The wok is first heated to a dull red glow over a high fire. The oil, seasonings, and meats are then added in rapid succession. The food is continually tossed, stopping only to add other ingredients such as broths, vegetables, or more seasonings. The purpose of Bao is to highlight natural tastes, so minimal seasoning is added.[23] Because of the high heat, bao is ideal for small amounts of food that cook quickly, so the juices do not flow out of the items.[24] Meat is coated with egg white or starch in order to contain the juices.[23] When the food is cooked it is poured and ladled out of the wok. The wok must then be quickly rinsed to prevent food residues from charring and burning to the wok bottom because of residual heat.

A larger amount of cooking fat with a high smoke point, such as refined plant oils, is often used in bao. The main ingredients are usually cut into smaller pieces to aid in cooking.