Deep frying is a cooking method in which food is submerged in hot fat, most oil, rather than the shallow oil used in conventional frying, done in a frying pan. A deep fryer or chip pan is used for this. Deep frying may be performed using oil, heated in a pot. Deep frying is classified as hot-fat cooking method. Deep frying foods cook quickly: all sides of a food are cooked as oil has a high rate of heat conduction; the term "deep frying" and many modern deep-fried foods were not invented until the 19th century, but the practice has been around for millennia. Early records and cookbooks suggest that the practice began in certain European countries before other countries adopted the practice. Deep frying is popular worldwide, with deep-fried foods accounting for a large portion of global caloric consumption. Many foods are deep-fried and cultures surrounding deep frying have developed, most notably in the Southern United States, where many events dedicated to deep frying food and non-edible items are held.
The English expression deep-fried is attested from the early 20th century. Frying food in olive oil is attested in Classical Greece from about the 5th century BCE; the late Roman cookbook of Apicius, appears to list the ancient Romans' first use of deep frying to prepare Pullum Frontonianum, a chicken dish. The practice of deep frying spread to other parts of Arabia in the following centuries. Deep-fried foods such as funnel cakes arrived in northern Europe by the 13th century, deep-fried fish recipes have been found in cookbooks in Spain and Portugal at around the same time. Falafel arrived in the Middle East from population migrations from Egypt as soon as the 14th century. Evidence of potato frying can be found as early as the late 17th century in Europe. French fries, invented in the late 18th century, became popular in the early 19th century western Europe. In 1860 Joseph Malin combined deep fried fish with chips to open the first fish and chip shop in London. Modern deep frying in the United States began in the 19th century with the growing popularity of cast iron around the American South which led to the development of many modern deep-fried dishes.
Doughnuts were invented in the mid-19th century, with foods such as onion rings, deep-fried turkey, corn dogs all being invented in the early 20th century. In recent years, the growth of fast food has expanded the reach of deep-fried foods French fries. Deep frying food is defined as a process where food is submerged in hot oil at temperatures between 350 °F and 375 °F. One common method for preparing food for deep frying involves adding multiple layers of batter around the food, such as cornmeal, flour, or tempura. After the food is submerged in oil, the surface of it begins to dehydrate and it undergoes Maillard reactions which break down sugars and proteins, creating the golden brown exterior of the food. Once the surface is dehydrated, it forms a crust; the heat conducts throughout the food causing proteins to denature, starches to undergo starch gelatinization, dietary fiber to soften. While most foods need batter coatings for protection, it is not as necessary for cooked noodles and potatoes because their high starch content enables them to hold more moisture and resist shrinking.
Meats may be cooked before deep frying to ensure. When performed properly, deep frying does not make food excessively greasy, because the moisture in the food repels the oil; the hot oil heats the water within the food. As long as the oil is hot enough and the food is not immersed in the oil for too long, oil penetration will be confined to the outer surface. Foods deep-fried at proper temperatures absorb "no more than a couple of tablespoons per 2 1⁄2 cups of oil" used; this oil absorption rate is around the same as occurs such as in a pan. However, if the food is cooked in the oil for too long, much of the water will be lost and the oil will begin to penetrate the food; the correct frying temperature depends on the thickness and type of food, but in most cases it lies between 350–375 °F. An informal test for a temperature close to this range involves adding a tiny amount of flour into the oil and watching to see if it sizzles without burning. A second test involves adding one piece of food to deep fry and watching it sink somewhat and rise back up.
Sinking without resurfacing indicates that the oil is too cold. It is recommended that deep fryers be cleaned to prevent contamination; the process of cooking with oil can contaminate nearby surfaces as oil may splatter on adjacent areas. Oil vapors can condense on more distant surfaces such as walls and ceilings. Supplies such as dish detergent and baking soda can clean affected surfaces. Deep frying is done with a deep fryer, a pan such as a wok or chip pan, a Dutch oven, or a cast-iron pot. Additional tools include fry baskets, which are used to contain foods in a deep fryer and to strain foods when removed from the oil, cooking thermometers, used to gauge oil temperature. Tongs, slotted spoons, wooden spoons, sieves may be used to remove or separate foods from the hot oil. Japanese deep frying tools include long metal chopsticks.
Convection is the heat transfer due to the bulk movement of molecules within fluids such as gases and liquids, including molten rock. Convection includes sub-mechanisms of advection, diffusion. Convection cannot take place in most solids because neither bulk current flows nor significant diffusion of matter can take place. Diffusion of heat takes place in rigid solids, but, called heat conduction. Convection, additionally may take place in soft solids or mixtures where solid particles can move past each other. Thermal convection can be demonstrated by placing a heat source at the side of a glass filled with a liquid, observing the changes in temperature in the glass caused by the warmer fluid circulating into cooler areas. Convective heat transfer is one of the major types of heat transfer, convection is a major mode of mass transfer in fluids. Convective heat and mass transfer takes place both by diffusion – the random Brownian motion of individual particles in the fluid – and by advection, in which matter or heat is transported by the larger-scale motion of currents in the fluid.
In the context of heat and mass transfer, the term "convection" is used to refer to the combined effects of advective and diffusive transfer. Sometimes the term "convection" is used to refer to "free heat convection" where bulk-flow in a fluid is due to temperature-induced differences in buoyancy, as opposed to "forced heat convection" where forces other than buoyancy move the fluid. However, in mechanics, the correct use of the word "convection" is the more general sense, different types of convection should be further qualified, for clarity. Convection can be qualified in terms of being natural, gravitational, granular, or thermomagnetic, it may be said to be due to combustion, capillary action, or Marangoni and Weissenberg effects. Heat transfer by natural convection plays a role in the structure of Earth's atmosphere, its oceans, its mantle. Discrete convective cells in the atmosphere can be seen as clouds, with stronger convection resulting in thunderstorms. Natural convection plays a role in stellar physics.
The convection mechanism is used in cooking, when using a convection oven, which uses fans to circulate hot air around food in order to cook the food faster than a conventional oven. The word convection may have different but related usages in different scientific or engineering contexts or applications; the broader sense is in fluid mechanics, where convection refers to the motion of fluid regardless of cause. However, in thermodynamics "convection" refers to heat transfer by convection. Convection occurs on a large scale in atmospheres, planetary mantles, it provides the mechanism of heat transfer for a large fraction of the outermost interiors of our sun and all stars. Fluid movement during convection may be invisibly slow, or it may be obvious and rapid, as in a hurricane. On astronomical scales, convection of gas and dust is thought to occur in the accretion disks of black holes, at speeds which may approach that of light. Convective heat transfer is a mechanism of heat transfer occurring because of bulk motion of fluids.
Heat is the entity of interest being advected, diffused. This can be contrasted with conductive heat transfer, the transfer of energy by vibrations at a molecular level through a solid or fluid, radiative heat transfer, the transfer of energy through electromagnetic waves. Heat is transferred by convection in numerous examples of occurring fluid flow, such as wind, oceanic currents, movements within the Earth's mantle. Convection is used in engineering practices of homes, industrial processes, cooling of equipment, etc; the rate of convective heat transfer may be improved by the use of a heat sink in conjunction with a fan. For instance, a typical computer CPU will have a purpose-made fan to ensure its operating temperature is kept within tolerable limits. A convection cell known as a Bénard cell is a characteristic fluid flow pattern in many convection systems. A rising body of fluid loses heat because it encounters a cold surface. In liquid, this occurs. In the example of the Earth's atmosphere, this occurs.
Because of this heat loss the fluid becomes denser than the fluid underneath it, still rising. Since it cannot descend through the rising fluid, it moves to one side. At some distance, its downward force overcomes the rising force beneath it, the fluid begins to descend; as it descends, it warms again and the cycle repeats itself. Atmospheric circulation is the large-scale movement of air, is a means by which thermal energy is distributed on the surface of the Earth, together with the much slower ocean circulation system; the large-scale structure of the atmospheric circulation varies from year to year, but the basic climatological structure remains constant. Latitudinal circulation occurs because incident solar radiation per unit area is highest at the heat equator, decreases as the latitude increases, reaching minima at the poles, it consists of two primary convection cells, the Hadley cell and the polar vortex, with the Hadley cell experiencing stronger convection due to the release of latent heat energy by condensation of water vapor at higher altitudes during cloud formation.
Longitudinal circulation, on the other hand, comes about because the ocean has a higher specific heat capacity than land (and thermal conduct
Sautéing or sauteing is a method of cooking that uses a small amount of oil or fat in a shallow pan over high heat. Various sauté methods exist, sauté pans are a specific type of pan designed for sautéing. Ingredients for sautéing are cut into pieces or thinly sliced to facilitate fast cooking; the primary mode of heat transfer during sautéing is conduction between the pan and the food being cooked. Food, sautéed is browned while preserving its texture and flavor. If meat, chicken, or fish is sautéed, the sauté is finished by deglazing the pan's residue to make a sauce. Sautéing may be compared with pan frying, in which larger pieces of food are cooked in oil or fat, flipped onto both sides; some cooks make a distinction between the two based on the depth of the oil used, while others use the terms interchangeably. Sautéing differs from searing in that searing only browns the surface of the food. Certain oils should not be used to sauté due to their low smoke point. Clarified butter, rapeseed oil and sunflower oil are used for sautéing.
For example, though regular butter would produce more flavor, it would burn at a lower temperature and more than other fats due to the presence of milk solids. Clarified butter is more fit for this use. In a sauté, all the ingredients are heated at once, cooked quickly. To facilitate this, the ingredients are moved around in the pan, either by the use of a utensil, or by jerking the pan itself. A sauté pan must be large enough to hold all of the food in one layer, so steam can escape, which keeps the ingredients from stewing and promotes the development of fond. Most pans sold as sauté pans have a wide flat base and low sides, to maximize the surface area available for heating; the low sides allow quick escape of steam. While skillets have flared or rounded sides, sauté pans have straight, vertical sides; this stirred. Only enough fat to coat the bottom of the pan is needed for sautéing; the food is spread across the hot fat in the pan, left to brown, turning or tossing for cooking. The sauté technique involves gripping the handle of the sauté pan and using a sharp elbow motion to jerk the pan back toward the cook, repeating as necessary to ensure the ingredients have been jumped.
Tossing or stirring the items in the pan by shaking the pan too however, can cause the pan to cool faster and make the sauté take longer. Sautéing Media related to Sautéing at Wikimedia Commons Sautéing at Wikibook Cookbooks
Baking is a method of cooking food that uses dry heat in an oven, but can be done in hot ashes, or on hot stones. The most common baked item is bread but many other types of foods are baked. Heat is transferred "from the surface of cakes and breads to their center; as heat travels through, it transforms batters and doughs into baked goods and more with a firm dry crust and a softer centre". Baking can be combined with grilling to produce a hybrid barbecue variant by using both methods or one after the other. Baking is related to barbecuing because the concept of the masonry oven is similar to that of a smoke pit; because of historical social and familial roles, baking has traditionally been performed at home by women for day-to-day meals and by men in bakeries and restaurants for local consumption. When production was industrialized, baking was automated by machines in large factories; the art of baking remains a fundamental skill and is important for nutrition, as baked goods breads, are a common and important food, both from an economic and cultural point of view.
A person who prepares baked goods as a profession is called a baker. All types of food can be baked. Various techniques have been developed to provide this protection. In addition to bread, baking is used to prepare cakes, pies, quiches, scones, crackers and more; these popular items are known collectively as "baked goods," and are sold at a bakery, a store that carries only baked goods, or at markets, grocery stores, farmers markets or through other venues. Meat, including cured meats, such as ham can be baked, but baking is reserved for meatloaf, smaller cuts of whole meats, or whole meats that contain stuffing or coating such as bread crumbs or buttermilk batter; some foods are surrounded with moisture during baking by placing a small amount of liquid in the bottom of a closed pan, letting it steam up around the food, a method known as braising or slow baking. Larger cuts prepared without stuffing or coating are more roasted, a similar process, using higher temperatures and shorter cooking times.
Roasting, however, is only suitable for finer cuts of meat, so other methods have been developed to make tougher meat cuts palatable after baking. One of these is the method known as en croûte, which protects the food from direct heat and seals the natural juices inside. Meat, game, fish or vegetables can be prepared by baking en croûte. Well-known examples include Beef Wellington; the en croûte method allows meat to be baked by burying it in the embers of a fire – a favorite method of cooking venison. Salt can be used to make a protective crust, not eaten. Another method of protecting food from the heat while it is baking is to cook it en papillote. In this method, the food is covered by baking paper to protect it; the cooked parcel of food is sometimes served unopened, allowing diners to discover the contents for themselves which adds an element of surprise. Eggs can be used in baking to produce savoury or sweet dishes. In combination with dairy products cheese, they are prepared as a dessert.
For example, although a baked custard can be made using starch, the flavor of the dish is much more delicate if eggs are used as the thickening agent. Baked custards, such as crème caramel, are among the items that need protection from an oven's direct heat, the bain-marie method serves this purpose; the cooking container is half submerged in water in another, larger one, so that the heat in the oven is more applied during the baking process. Baking a successful soufflé requires that the baking process be controlled; the oven temperature must be even and the oven space not shared with another dish. These factors, along with the theatrical effect of an air-filled dessert, have given this baked food a reputation for being a culinary achievement. A good baking technique are needed to create a baked Alaska because of the difficulty of baking hot meringue and cold ice cream at the same time. Baking can be used to prepare other foods such as pizzas, baked potatoes, baked apples, baked beans, some casseroles and pasta dishes such as lasagne.
The first evidence of baking occurred when humans took wild grass grains, soaked them in water, mixed everything together, mashing it into a kind of broth-like paste. The paste was cooked by resulting in a bread-like substance; when humans mastered fire, the paste was roasted on hot embers, which made bread-making easier, as it could now be made any time fire was created. The world's oldest oven was discovered in Croatia in 2014 dating back 6500 years ago; the Ancient Egyptians baked bread using yeast, which they had been using to brew beer. Bread baking began in Ancient Greece around 600 BC. "Ovens and worktables have been discovered in archaeological digs from Turkey to Palestine and date back to 5600 BC."Baking flourished during the Roman Empire. Beginning around 300 B. C. the pastry cook became an occupation for Romans and became a respected profession because pastries were considered decadent, Romans loved festivity and celebration. Thus, pastr
Poaching is a type of moist-heat cooking technique that involves cooking by submerging food in a liquid, such as water, stock or wine or in a tray. Poaching is differentiated from the other "moist heat" cooking methods, such as simmering and boiling, in that it uses a low temperature; this temperature range makes it suitable for delicate food, such as eggs, poultry and fruit, which might fall apart or dry out using other cooking methods. Poaching is considered a healthy method of cooking because it does not use fat to cook or flavor the food; this moist-heat cooking method uses a sautoire or other shallow cooking vessel, heat is transferred by conduction from the pan, to the liquid, to the food. Shallow poaching is best suited for boneless tender, single serving size, sliced or diced pieces of "meat", poultry or fish; this preparation involves smearing the inside of the pan with whole butter and adding aromatics into the pan. The items to be cooked are placed on top of the aromatics presentation side up.
Cold poaching liquid is poured in until the product is submerged heated. The liquid should never be kept as close to boiling as possible. A more contemporary technique of shallow poaching involves BPA-free plastic bags and is convenient for the home cook; this technique is similar to shallow poaching but the product is submerged. The pot used for deep poaching should hold the food and aromatics comfortably, with enough room to allow the liquid to expand as it heats. There should be enough space so that the surface can be skimmed if necessary throughout cooking. A tight-fitting lid may be helpful for bringing the liquid up to temperature; the poaching liquid traditionally uses a court bouillon which consists of an acid and aromatics, although any flavorful liquid can be used in poaching. The liquid should ideally be around 160–185 °F, but when poaching chicken, it is vital that the chicken reach an internal temperature of at least 165 °F in the core, in order to be ingested safely. A significant amount of flavor is transferred from the food to the cooking liquid.
For maximum flavor, the cooking liquid is reduced and used as the base for a sauce. Poached eggs are cooked in water and vinegar, fish in white wine, poultry in stock and fruit in red wine; the liquid used for shallow poaching is called a cuisson, can be reduced and used as a base for the poached item's sauce. Poaching allows the proteins to denature without pulling out too much moisture out of the food. For this reason, it is important to keep the heat low and to keep the poaching time to a bare minimum, which will preserve the flavor of the food. An egg is poached just to the point where the white is no longer runny and the yolk is beginning to harden around the edges; some people say creating a whirlpool helps with poaching eggs because it helps the egg stay together, wrapping the white around the yolk. Water is a efficient conductor of heat, but it has a low limit to its maximum potential temperature; as such, it is a technique that applies itself to a broad spectrum of results. It is used to regulate food at a low temperature for extended periods, as with sous-vide.
It is used to raise the temperature of foods, as with blanching. Poaching itself is part of a family of moist-heat cooking methods but separates itself in that it is for delicate foods such as eggs. Simmering uses a higher temperature for cooking, because it surrounds the food in water that maintains a more or less constant temperature, simmering cooks food evenly. Boiling uses the absolute highest temperature for water and is least to be used in cooking delicate foods. While it cannot achieve caramelization, which to many is desirable, many find the delicate nuance of so-called "blanc" foods pleasant. Poaching is confused with stewing, as both techniques involve cooking through simmering. However, the purpose of poaching is to cook while retaining the basic shape and structure of the food, rather than to soften it, as with stewing. Poached egg Sous-vide Tips and Tricks for poaching eggs Recipes and tips for poaching food How to Poach an Egg at b3ta.com
Infrared radiation, sometimes called infrared light, is electromagnetic radiation with longer wavelengths than those of visible light, is therefore invisible to the human eye, although IR at wavelengths up to 1050 nanometers s from specially pulsed lasers can be seen by humans under certain conditions. IR wavelengths extend from the nominal red edge of the visible spectrum at 700 nanometers, to 1 millimeter. Most of the thermal radiation emitted by objects near room temperature is infrared; as with all EMR, IR carries radiant energy and behaves both like a wave and like its quantum particle, the photon. Infrared radiation was discovered in 1800 by astronomer Sir William Herschel, who discovered a type of invisible radiation in the spectrum lower in energy than red light, by means of its effect on a thermometer. More than half of the total energy from the Sun was found to arrive on Earth in the form of infrared; the balance between absorbed and emitted infrared radiation has a critical effect on Earth's climate.
Infrared radiation is emitted or absorbed by molecules when they change their rotational-vibrational movements. It excites vibrational modes in a molecule through a change in the dipole moment, making it a useful frequency range for study of these energy states for molecules of the proper symmetry. Infrared spectroscopy examines transmission of photons in the infrared range. Infrared radiation is used in industrial, military, law enforcement, medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space such as molecular clouds, detect objects such as planets, to view red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, to detect overheating of electrical apparatus. Extensive uses for military and civilian applications include target acquisition, night vision and tracking.
Humans at normal body temperature radiate chiefly at wavelengths around 10 μm. Non-military uses include thermal efficiency analysis, environmental monitoring, industrial facility inspections, detection of grow-ops, remote temperature sensing, short-range wireless communication and weather forecasting. Infrared radiation extends from the nominal red edge of the visible spectrum at 700 nanometers to 1 millimeter; this range of wavelengths corresponds to a frequency range of 430 THz down to 300 GHz. Below infrared is the microwave portion of the electromagnetic spectrum. Sunlight, at an effective temperature of 5,780 kelvins, is composed of near-thermal-spectrum radiation, more than half infrared. At zenith, sunlight provides an irradiance of just over 1 kilowatt per square meter at sea level. Of this energy, 527 watts is infrared radiation, 445 watts is visible light, 32 watts is ultraviolet radiation. Nearly all the infrared radiation in sunlight is shorter than 4 micrometers. On the surface of Earth, at far lower temperatures than the surface of the Sun, some thermal radiation consists of infrared in the mid-infrared region, much longer than in sunlight.
However, black body or thermal radiation is continuous: it gives off radiation at all wavelengths. Of these natural thermal radiation processes, only lightning and natural fires are hot enough to produce much visible energy, fires produce far more infrared than visible-light energy. In general, objects emit infrared radiation across a spectrum of wavelengths, but sometimes only a limited region of the spectrum is of interest because sensors collect radiation only within a specific bandwidth. Thermal infrared radiation has a maximum emission wavelength, inversely proportional to the absolute temperature of object, in accordance with Wien's displacement law. Therefore, the infrared band is subdivided into smaller sections. A used sub-division scheme is: NIR and SWIR is sometimes called "reflected infrared", whereas MWIR and LWIR is sometimes referred to as "thermal infrared". Due to the nature of the blackbody radiation curves, typical "hot" objects, such as exhaust pipes appear brighter in the MW compared to the same object viewed in the LW.
The International Commission on Illumination recommended the division of infrared radiation into the following three bands: ISO 20473 specifies the following scheme: Astronomers divide the infrared spectrum as follows: These divisions are not precise and can vary depending on the publication. The three regions are used for observation of different temperature ranges, hence different environments in space; the most common photometric system used in astronomy allocates capital letters to different spectral regions according to filters used. These letters are understood in reference to atmospheric windows and appear, for instance, in the titles of many papers. A third scheme divides up the band based on the response of various detectors: Near-infrared: from 0.7 to 1.0 µm. Short-wave infrared: 1.0 to 3 µm. InGaAs covers to about 1.8 µm. Mid-wave infrared: 3 to 5 µm (defined by the atmospheric window and covered by indium antimonide and mercury cadmium telluride and by lead
Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmosphere. There are two main types of boiling: nucleate boiling where small bubbles of vapour form at discrete points, critical heat flux boiling where the boiling surface is heated above a certain critical temperature and a film of vapor forms on the surface. Transition boiling is an unstable form of boiling with elements of both types; the boiling point of water is 100 °C or 212 °F but is lower with the decreased atmospheric pressure found at higher altitudes. Boiling water is used as a method of making it potable by killing microbes; the sensitivity of different micro-organisms to heat varies, but if water is held at 70 °C for ten minutes, many organisms are killed, but some are more resistant to heat and require one minute at the boiling point of water. Boiling is used in cooking.
Foods suitable for boiling include vegetables, starchy foods such as rice and potatoes, eggs, "meats", sauces and soups. As a cooking method, it is suitable for large-scale cookery. Tough meats or poultry can be given a long, slow cooking and a nutritious stock is produced. Disadvantages include loss of water-soluble minerals. Commercially prepared foodstuffs are sometimes packed in polythene sachets and sold as "boil-in-the-bag" products. Nucleate boiling is characterized by the growth of bubbles or pops on a heated surface, which rises from discrete points on a surface, whose temperature is only above the liquids. In general, the number of nucleation sites are increased by an increasing surface temperature. An irregular surface of the boiling vessel or additives to the fluid can create additional nucleation sites, while an exceptionally smooth surface, such as plastic, lends itself to superheating. Under these conditions, a heated liquid may show boiling delay and the temperature may go somewhat above the boiling point without boiling.
As the boiling surface is heated above a critical temperature, a film of vapor forms on the surface. Since this vapor film is much less capable of carrying heat away from the surface, the temperature rises rapidly beyond this point into the transition boiling regime; the point at which this occurs is dependent on the characteristics of boiling fluid and the heating surface in question. Transition boiling may be defined as the unstable boiling, which occurs at surface temperatures between the maximum attainable in nucleate and the minimum attainable in film boiling; the formation of bubbles in a heated liquid is a complex physical process which involves cavitation and acoustic effects, such as the broad-spectrum hiss one hears in a kettle not yet heated to the point where bubbles boil to the surface. If a surface heating the liquid is hotter than the liquid film boiling will occur, where a thin layer of vapor, which has low thermal conductivity, insulates the surface; this condition of a vapor film insulating the surface from the liquid characterizes film boiling.
As a method of disinfecting water, bringing it to its boiling point at 100 °C, is the oldest and most effective way since it does not affect the taste, it is effective despite contaminants or particles present in it, is a single step process which eliminates most microbes responsible for causing intestine related diseases. Water's boiling point rests at around 100.0 degrees Celsius, when at an elevation of 0. In places having a proper water purification system, it is recommended only as an emergency treatment method or for obtaining potable water in the wilderness or in rural areas, as it cannot remove chemical toxins or impurities; the elimination of micro-organisms by boiling follows first-order kinetics—at high temperatures, it is achieved in less time and at lower temperatures, in more time. The heat sensitivity of micro-organisms varies, at 70 °C, Giardia species can take ten minutes for complete inactivation, most intestine affecting microbes and E. coli take less than a minute. Boiling does not ensure the elimination of all micro-organisms.
Thus for human health, complete sterilization of water is not required. The traditional advice of boiling water for ten minutes is for additional safety, since microbes start getting eliminated at temperatures greater than 60 °C and bringing it to its boiling point is a useful indication that can be seen without the help of a thermometer, by this time, the water is disinfected. Though the boiling point decreases with increasing altitude, it is not enough to affect the disinfecting process. Boiling is the method of cooking food in boiling water or other water-based liquids such as stock or milk. Simmering is gentle boiling; the boiling point of water is considered to be 100 °C or 212 °F. Pressure and a change in the composition of the liquid may alter the boiling point of the liquid. For this reason, high elevation cooking takes longer since boiling point is a function of atmospheric pressure. In Denver, Colorado, USA, at an elevation of about one mile, water boils at 95 °C or 203 °F. Depending on the type of food and the elevation, the boiling water may not be hot enough to cook the food properly.