39-852: Oil is any of a number of nonpolar, hydrophobic, and viscous liquids. Oil also often refers to: Oil or OIL may also refer to: Oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water ) and lipophilic (mixes with other oils). Oils are usually flammable and surface active . Most oils are unsaturated lipids that are liquid at room temperature. The general definition of oil includes classes of chemical compounds that may be otherwise unrelated in structure, properties, and uses. Oils may be animal , vegetable , or petrochemical in origin, and may be volatile or non-volatile. They are used for food (e.g., olive oil ), fuel (e.g., heating oil ), medical purposes (e.g., mineral oil ), lubrication (e.g. motor oil ), and
78-525: 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." When read in Mandarin, the second character is transliterated as qi ( ch'i according to its Wade-Giles romanization, so wok hei
117-792: A barrel of crude into various products results in an increase to 45 US gallons (37 imp gal; 170 L). In the 18th and 19th centuries, whale oil was commonly used for lamps, which was replaced with natural gas and then electricity. Crude oil can be refined into a wide variety of component hydrocarbons . Petrochemicals are the refined components of crude oil and the chemical products made from them. They are used as detergents , fertilizers , medicines , paints , plastics , synthetic fibers , and synthetic rubber . Organic oils are another important chemical feedstock, especially in green chemistry . Stir frying Stir frying ( Chinese : 炒 ; pinyin : chǎo ; Wade–Giles : ch'ao ; Cantonese Yale : cháau )
156-409: A high flame while being stirred and tossed quickly. 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
195-632: A much greater loss of chlorophyll , soluble protein, soluble sugar and vitamin C. The method which affected these values the least was steaming. Stir frying for five minutes and stir frying combined with boiling caused the highest loss of glucosinolates , which according to this study are best preserved by steaming. A study performed by the Spanish National Research Counsel stir-fried the broccoli for only three minutes and thirty seconds and found that nutritional value of these broccoli samples varied depending on which cooking oil
234-678: A reasonable level. The English-language term "stir-fry" was coined and introduced in Buwei Yang Chao , How to Cook and Eat in Chinese (1945) to translate the Chinese term chǎo 炒. Although using "stir-fry" as a noun is commonplace in English, in Chinese, chǎo is used as a verb or adjective only. The Chinese character 炒 is attested in inscriptions on bronze vessels from the Eastern Zhou period (771–256 BC), but not in
273-407: A religious medium. It is often considered a spiritually purifying agent and is used for anointing purposes. As a particular example, holy anointing oil has been an important ritual liquid for Judaism and Christianity . Oils have been consumed since ancient times. Oils hold lots of fats and medical properties. A good example is olive oil. Olive oil holds a lot of fats within it which is why it
312-593: 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. Historically, stir frying
351-617: A small amount of cooking oil is added down the side of the wok (a traditional expression is 热锅冷油 "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 . A single ingredient, especially
390-460: 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: wok hei ) romanization
429-445: 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-fried dishes could be prepared in as little as fifteen minutes. Broadly speaking, there are two primary techniques: chao and bao . Both techniques use high heat, but chao adds a liquid and the ingredients are softer, whereas bao stir fries are more crispy because of
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#1732786763466468-627: Is a cooking technique in which ingredients are fried in a small amount of very hot oil while being stirred or tossed in a wok . The technique originated in China and in recent centuries has spread into other parts of Asia and the West. It is similar to sautéing in Western cooking technique. Wok frying may have been used as early as the Han dynasty (206 BC – 220 AD) for drying grain, not for cooking. It
507-605: Is based on the Cantonese Chinese pronunciation of the phrase; when literally translated into English, it can be translated as "wok thermal radiation " 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 . In her book, The Breath of a Wok , Young further explores the ideas and concepts of wok hei . An essay called "Wok Hay: The Breath of
546-399: Is done so quickly, it can be called 'blitz-cooking.' Although using the term "stir-fry" as a noun is commonplace in English, in Chinese, the word 炒 (chǎo) is used as a verb or adjective only. In the West, stir frying 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
585-412: 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. Because of the high heat, bao is ideal for small amounts of food that cook quickly, so
624-1202: Is no evidence that NASA has used whale oil. Some oils burn in liquid or aerosol form, generating light , and heat which can be used directly or converted into other forms of energy such as electricity or mechanical work. In order to obtain many fuel oils, crude oil is pumped from the ground and is shipped via oil tanker or a pipeline to an oil refinery . There, it is converted from crude oil to diesel fuel (petrodiesel), ethane (and other short-chain alkanes ), fuel oils (heaviest of commercial fuels, used in ships/furnaces), gasoline (petrol), jet fuel , kerosene , benzene (historically), and liquefied petroleum gas . A 42-US-gallon (35 imp gal; 160 L) barrel of crude oil produces approximately 10 US gallons (8.3 imp gal; 38 L) of diesel, 4 US gallons (3.3 imp gal; 15 L) of jet fuel, 19 US gallons (16 imp gal; 72 L) of gasoline, 7 US gallons (5.8 imp gal; 26 L) of other products, 3 US gallons (2.5 imp gal; 11 L) split between heavy fuel oil and liquified petroleum gases, and 2 US gallons (1.7 imp gal; 7.6 L) of heating oil. The total production of
663-405: Is not without health risks . Recent studies show that heterocyclic amines and polycyclic aromatic hydrocarbons are formed by stir frying meat at very high temperatures . These chemicals may cause DNA changes that may contribute to increased risk of cancer . The process of stir-frying is used in the preparation of some Chinese herbal medicines under the term 'dry-frying'. Stir frying
702-644: Is preferred for lubricating clocks, because it does not evaporate, leaving dust, although its use was banned in the US in 1980. It is a long-running myth that spermaceti from whales has still been used in NASA projects such as the Hubble Space Telescope and the Voyager probe because of its extremely low freezing temperature. Spermaceti is not actually an oil, but a mixture mostly of wax esters, and there
741-465: Is remote (and was unknown at the time of its discovery), and because it is obtained in the vicinity of rocks, underground traps, and sands. Mineral oil also refers to several specific distillates of crude oil. Several edible vegetable and animal oils, and also fats , are used for various purposes in cooking and food preparation. In particular, many foods are fried in oil much hotter than boiling water. Oils are also used for flavoring and for modifying
780-544: 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. 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 concept in some of the others. To impart wok hei the traditional way, the food is cooked in a seasoned wok over
819-464: The Suiyuan shidan ". 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. Stir frying was brought to America by early Chinese immigrants , and has been used in non-Asian cuisine. The term "stir fry" as a translation for "chao"
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#1732786763466858-476: The Maillard reaction . The chao (炒) technique is similar to the Western technique of sautéing . 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,
897-896: The excess grime and creating a layer where new grime could form but be easily washed off in the water as oil is hydrophobic. Fish oils hold the omega-3 fatty acid. This fatty acid helps with inflammation and reduces fat in the bloodstream. Color pigments are easily suspended in oil, making it suitable as a supporting medium for paints . The oldest known extant oil paintings date from 650 AD. Oils are used as coolants in oil cooling , for instance in electric transformers . Heat transfer oils are used both as coolants (see oil cooling ), for heating (e.g. in oil heaters ) and in other applications of heat transfer. Given that they are non-polar, oils do not easily adhere to other substances. This makes them useful as lubricants for various engineering purposes. Mineral oils are more commonly used as machine lubricants than biological oils are. Whale oil
936-440: The food at very high heat in excess of 200 °C (392 °F). Aside from flavour, wok hei also manifests itself in the texture and smell of the cooked items. 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 . The wok
975-513: The juices do not flow out of the items. Meat is coated with egg white or starch in order to contain the juices. 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. Writers extol
1014-487: The late Ming and Qing (1644–1912) periods also favored speedy methods. 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,
1053-496: The manufacture of many types of paints, plastics, and other materials. Specially prepared oils are used in some religious ceremonies and rituals as purifying agents. First attested in English 1176, the word oil comes from Old French oile , from Latin oleum , which in turn comes from the Greek ἔλαιον ( elaion ), "olive oil, oil" and that from ἐλαία ( elaia ), " olive tree", "olive fruit". The earliest attested forms of
1092-412: The modern economy. Crude oil originates from ancient fossilized organic materials , such as zooplankton and algae , which geochemical processes convert into oil. The name "mineral oil" is a misnomer , in that minerals are not the source of the oil—ancient plants and animals are. Mineral oil is organic. However, it is classified as "mineral oil" instead of as "organic oil" because its organic origin
1131-511: The quick cooking at high heat for retaining color, texture, and nutritional value. One study compared the effects of boiling, steaming, and stir frying on bamboo shoots . Boiling and steaming decreased the amount of protein , soluble sugar, ash, and total free amino acids by more than one-third. Stir-frying bamboo shoots increased their fat content by 528.57% due to the addition of oil. With 78.9% retention, stir frying preserved significantly more vitamin C than boiling. Taking into consideration
1170-468: The sense of stir frying. Dry stirring was used in the Han dynasty (206 BC – 220 AD) to parch grain. 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. The term initially appears in the sense of "stir frying" in the Qimin Yaoshu (齊民要術),
1209-399: The texture of foods (e.g. stir fry ). Cooking oils are derived either from animal fat, as butter , lard and other types, or plant oils from olive , maize , sunflower and many other species. Oils are applied to hair to give it a lustrous look, to prevent tangles and roughness and to stabilize the hair to promote growth. See hair conditioner . Oil has been used throughout history as
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1248-566: The total retention of nutrients, the study concluded that stir frying is the method best suited for bamboo shoots. Similar results were found for stir frying red peppers. Another study examined the nutritional value of broccoli after five common cooking techniques: steaming, boiling, microwaving, stir-frying and stir-frying followed by deep frying. The study found that the two most common methods of home cooking in China, stir-frying and stir-frying combined with deep frying in soybean oil , resulted in
1287-533: The way that they are made by an organism, their chemical structure and their limited solubility in water compared to oils. They have a high carbon and hydrogen content and are considerably lacking in oxygen compared to other organic compounds and minerals; they tend to be relatively nonpolar molecules, but may include both polar and nonpolar regions as in the case of phospholipids and steroids. Crude oil, or petroleum , and its refined components, collectively termed petrochemicals , are crucial resources in
1326-786: The word are the Mycenaean Greek 𐀁𐀨𐀺 , e-ra-wo and 𐀁𐁉𐀺 , e-rai-wo , written in the Linear B syllabic script. Organic oils are produced in remarkable diversity by plants, animals, and other organisms through natural metabolic processes. Lipid is the scientific term for the fatty acids , steroids and similar chemicals often found in the oils produced by living things, while oil refers to an overall mixture of chemicals. Organic oils may also contain chemicals other than lipids, including proteins , waxes (class of compounds with oil-like properties that are solid at common temperatures) and alkaloids . Lipids can be classified by
1365-419: Was also used in lighting in ancient Greece and Rome. So people would use it to bulk out food so they would have more energy to burn through the day. Olive oil was also used to clean the body in this time as it would trap the moisture in the skin while pulling the grime to the surface. It was used as an ancient form of unsophisticated soap. It was applied on the skin then scrubbed off with a wooden stick pulling off
1404-400: Was coined in the 1945 book How To Cook and Eat in Chinese , by Buwei Yang Chao. 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
1443-426: 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), 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. "The increasingly commercial nature of city life" in
1482-591: Was not until the Ming dynasty (1368–1644) that the wok reached its modern shape and allowed quick cooking in hot oil. However, there is research indicating that metal woks and stir-frying of dishes were already popular in the Song dynasty (960–1279), and stir-frying as a cooking technique is mentioned in the 6th-century AD Qimin Yaoshu . Stir frying has been recommended as a healthy and appealing method of preparing vegetables, meats, and fish, provided calories are kept at
1521-463: Was used. Comparing these results to an uncooked sample, the study found that phenolics and vitamin C were reduced more than glucosinolates and minerals. Stir-frying with soybean, peanut, safflower or extra virgin olive oil did not reduce glucosinolates , and broccoli stir-fried with extra virgin olive oil or sunflower oil had vitamin C levels similar to uncooked broccoli . These levels were significantly lower with other edible oils . Stir frying
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