1. Relationship between cooking temperature and raw materials. There are many kinds of raw materials for dishes, including old, tender, hard and soft. The application of cooking temperature should be determined according to the texture of raw materials. Soft, tender and crisp raw materials are cooked quickly with strong fire, while old, hard and tough raw materials are cooked for a long time with low fire. However, if the texture and characteristics of raw materials are changed by preliminary processing before cooking, the application of heat should also be changed. For example, chopping raw materials, degreasing and blanching can shorten cooking time. The amount of raw materials is also related to the degree of heat. The smaller the number, the weaker the firepower and the shorter the time. The shape of raw materials is also directly related to the use of heat. Generally speaking, in cooking, large pieces of plastic raw materials take a long time to mature because of the small heating area, so the firepower should not be too strong. However, raw materials with small shapes can be cured in a hurry because of the large heating area.
2. The relationship between temperature and conduction mode In cooking, the conduction of fire is the decisive factor for the qualitative change of cooking materials. The conduction modes are radiation, conduction and convection. Heat transfer media can be divided into non-medium heat transfer and medium heat transfer, such as water, oil, steam, salt, sand and so on. These different heat transfer modes directly affect the application of cooking temperature.
3. The relationship between heat and cooking technology. Cooking technology is closely related to the use of heat. The techniques of frying, frying, boiling and frying are fast and fast. Burning, stewing, boiling, stewing and other techniques are often cooked for a long time with small fire. However, according to the requirements of dishes, each cooking technique is not immutable in the use of heat. Only by combining various factors in cooking can heat be used correctly. Here are three application examples to illustrate.
(l) Dishes cooked with a small fire, such as beef stew, are all cooked with a small fire. Before cooking, cut the beef into squares and blanch it with boiling water to remove blood foam and impurities. At this time, the fiber of beef is in the contraction stage, so it needs to be moved to medium fire, added with auxiliary materials, boiled for a while, and then moved to low fire, so that the contracted fiber of beef can be gradually extended. When the beef is almost cooked, add seasoning and stew until cooked, so that the stewed beef has good color, flavor and shape. If you cook beef with high fire, the appearance of beef will be irregular. In addition, there will be a lot of beef residue in vegetable soup, which will make the soup turbid and easy to form cooked noodles, which are still chewy. Therefore, dishes with large raw materials should be cooked on low heat.
(2) Medium fire is suitable for frying vegetables. When frying raw materials with paste on the outside, the method of gradually frying oil in medium fire is more effective. Because if you use strong fire when frying, the raw materials will be enlarged immediately, forming external coke. If you use a small fire, the raw materials will come out and paste after cooking. Some dishes, such as crispy chicken, are fried in a pot during a big fire, with a hard shell, and then fried in medium heat until crisp.
(3) Wanghuo is suitable for fried, fried and rinsed dishes. Generally, the dishes cooked by Wanghuo are mainly crisp and tender, such as fried mutton with onions, boiled mutton and so on. When boiling water, it must be cooked inside and outside, so that it will be crisp and tender. The reason is that the dishes cooked by Wanghuo can make the main ingredients exposed to high temperature quickly, and the fiber shrinks sharply, which makes the water in the meat difficult to leach out and tastes crisp and tender. If you don't use strong fire, the heat is insufficient, the water in the pot can't boil, and the main ingredients can't shrink in time, you will boil the main ingredients. Another example is the mutton with onion, which looks simple, but some people either make a lot of soup or can't chew it. What can I do to do it well? First of all, the meat should be cut well, and the meat should be cut with the top knife method. Secondly, it must be heated with fire and oil. Put the wok on the fire, put the oil until it emits lampblack, then fry the human flesh until it changes color, immediately add the onion and seasoning and stew for a while, and then take it out of the pot immediately after it changes color. It is also necessary to make a quick decision, otherwise it will cause too much water and chewing.
But now the general household gas stove can only produce three kinds of fires, small, medium and large, which can not meet the requirements of prosperous fire. Stir-fry the dishes cooked by strong fire with medium or small fire. First, increase the amount of oil in the pot appropriately, then heat for a little longer, and then put less raw materials, so as to achieve better results.
Respondent: gabjwjjwd- Guard Corps 12 Commander 7-3 16:29.
Concept of heat: Cooking is generally heated by fire. In the heating process, because the raw materials used in cooking dishes are various, there are old, soft, tender and hard local materials; Shapes are large and small, thick and thin; Production requirements need to be crisp, some need to be tender, and some need to be crisp. Therefore, in the cooking process, different firepower should be used to heat the raw materials according to the specific situation, which is called mastering the heat.
Simply put, the heat is the change of firepower, and mastering the heat is to master the heat and time when heating the raw materials of dishes to meet the requirements of cooking.
2. The function of heat: The raw materials and condiments used in cooking dishes will change at different temperatures after being heated by fire to meet different cooking requirements. Proper cooking can get rid of the fishy smell and taste of raw materials, highlight the delicacy of raw materials and become a good dish; On the contrary, although there are good raw materials and condiments, it is also possible to make dishes with poor quality.
In a word, the mastery of cooking temperature plays a very important role in the formation of color, aroma, taste and shape of dishes. Now many cookbooks define it as "the size of firepower and the length of heating time". This is actually not the essence of temperature, but the expression of a phenomenon. With the development of modern science and technology, more and more new scientific discoveries are applied to cooking. For example, the emergence of microwave ovens, the development of electromagnetic waves, the use of electric energy and so on. The traditional heating method has been greatly innovated, and the heating has changed from naked to naked, which makes the heating of food safer, more hygienic and easier to operate, and opens up a broad space for food cooking.
From this point of view, it is obviously wrong that the definition of temperature can only cover everything with fire, because new discoveries in science and technology always bring many surprises to people. For example, electrified heating developed in the early 1980s is widely used in food industry in Europe, America and Japan, which can solve the problems of uneven microwave heating and excessive energy consumption in traditional heating.
But no matter which heating method, it generally includes three parts: heat source, heat transfer medium and raw material. For heat source, it refers to how much heat is generated per unit time; For heat transfer medium, it refers to the temperature reached by the heat transfer medium in unit time and the heat supplied to food; For raw materials, it refers to the speed at which the temperature of raw materials rises per unit time. It can be seen that temperature and time are two key factors, and changing any one factor will cause different changes in heat and different results in food heating. Of course, the size, texture, quantity of raw materials, types of media and seasonal changes will all affect the cooking time, so it is necessary to adjust the heating temperature and time according to the above changes to make the variety of dishes achieve the ideal effect. In a word, the heat is to control the intensity of heat source and the length of heating time according to the nature and shape of different raw materials, different cooking methods and taste requirements, so as to obtain the appropriate temperature for cooking from raw to cooked. It can be seen that heat is a sign of food maturity.
In the traditional cooking operation, the chef grasps the cooking temperature more through the phenomenon, as Yuan Mei said in the "Notes on the Heating Temperature", "The method of cooking is the most important. If you need a useful fire, you should also fry it. If the fire is weak, you will run out of things. If there is a need for slow fire, it should also be slow. If the fire is big, things will dry. People who use strong fire first and then slow fire will get soup, but if they are impatient, they will burn the skin and make the inside uncooked. Some are tender when cooked, such as kidneys and eggs, while others are not tender when slightly cooked, such as fresh fish and clams. The meat rises late, the red turns black, the fish rises late, and the live meat becomes dead. Repeatedly open the lid, the foam is more fragrant and less fragrant. When the fire is extinguished, the oil is gone and the taste is gone. Taoist turned Dan into nine immortals, while Confucianism centered on no fault. Chefs can know the temperature and wait, which is natural. When fish is eaten, its color is as white as jade. Those who coagulate but don't disperse, live meat is as white as powder, and those who don't stick, dead meat is also. It is obviously a fresh fish, and it is not fresh and extremely hateful. " Chefs judge temperature and time by grasping phenomena, such as oil temperature by turning and lampblack, and time by texture of raw materials and color change of blood. This makes the accumulation of experience more important, because rich experience can make the phenomenal temperature and time closer to the essential temperature and time of raw materials. Of course, the accumulation of experience is not built in a day, which brings a lot of inconvenience to beginners. In view of this, in order to grasp the temperature, we need the guidance of cooking theory. Because the research of cooking theory is to reflect the essence of cooking, use scientific data to guide production practice, and then use more scientific heating equipment to control cooking, thus reducing the probability of failure and grasping the true meaning of cooking faster and better.
Second, the nature of temperature
According to traditional experience, people are used to regard temperature as a clever combination of the size of furnace mouth firepower and the length of heating time. In fact, this conventional knowledge does not reflect the essence of temperature, but only the form of temperature (a temperature form that is not fully summarized). So, what is the nature of temperature? The cooking process tells us that the change of raw materials from raw to cooked is that the heat energy released by the heat source is transferred to the raw materials through the heat transfer medium, which makes the raw materials undergo certain physical and chemical changes. Therefore, to reveal the essence of cooking, we must consider the transfer and utilization of heat energy in cooking.
In essence, temperature is the heat that needs to be absorbed when the raw materials change moderately in a certain way during cooking. The "certain way" here refers to the type and quantity of heat transfer media used in cooking, and the change of raw materials from surface to inside to meet the cooking requirements when they are put into heating. "A certain way" determines the heat that the heat transfer medium can provide in cooking, and "moderate change" determines the heat that raw materials need to get from the heat transfer medium in a certain period of time. The true meaning of temperature lies in the latter. Because in the cooking process of dishes, no matter what kind of heat source is used, no matter what form the heat source releases heat, no matter what kind of heat transfer medium is used, no matter how much heat transfer medium is used, no matter how high or low the temperature, the raw materials absorb the required heat in a certain period of time and change with the cooking requirements.
In the cooking process, raw materials change from raw to cooked, which is often accompanied by protein denaturation, starch gelatinization, caramelization action, carbonyl ammonia reaction, and a series of complex physical and chemical changes such as oxidation, hydrolysis, decomposition, esterification, diffusion, infiltration, melting, solidification, evaporation and condensation. Only if this change is "moderate" can the dishes meet the predetermined quality requirements. In cooking practice, mastering cooking temperature means controlling the heat absorbed by raw materials in a certain period of time to make them undergo moderate physical and chemical changes to meet the quality requirements of dishes.
Third, the element of temperature.
If heat is regarded as the heat that needs to be absorbed when raw materials change moderately in a certain period of time, then it can be considered that heat source firepower, heat medium temperature and heating time are the three necessary elements to form heat.
1, heat source firepower. Here, it does not simply refer to "flame intensity", but refers to the heat flow at the mouth of the furnace or in the heating direction when the fuel is burned, including how much electric energy is converted into heat energy per unit time. The size of combustion firepower is influenced by the internal quality of fuel, combustion conditions, flame temperature, heat transfer area and heat transfer distance. Under the condition of constant fuel type and stove composition, the amount of firepower can be changed by changing the fuel combustion in unit time, so as to adjust the combustion conditions, flame temperature, heat transfer area and heat transfer distance. The "firepower" of electric energy is mainly controlled by heating equipment, which can be adjusted by adjusting the components on the equipment. The firepower of the heat source can be accurately measured. For heating with electric energy as heat source, basic data have been measured during equipment design. However, the heating with fuel as heat source in cooking is mainly judged by experience. People usually combine the phenomena of flame color, luminosity, shape and thermal radiation to classify fuel firepower into four categories: strong fire, medium fire, small fire and slight fire. If we refer to the experimental data about firepower (to be determined) and combine with experience, the result will be more accurate.
2. Heat medium temperature. It can also be called heating temperature, which refers to the degree of heat and cold of the heated environment of raw materials during cooking. It is an indispensable element of temperature, which was often overlooked when people expounded temperature in the past. Cooking practice tells us that the energy released by the heat source must be carried by the heat medium before it can directly act on the raw materials, or it can act on the raw materials after conversion. In order to make the raw materials get enough heat and change moderately in a certain period of time, it is generally required that the heat medium must have an appropriate high temperature. For example, the oil temperature of sizing raw materials should be kept at 40% ~ 50%, otherwise it will either "take off the robe" or the surface of raw materials will become hard and the texture will become old. Another example is: cooking, which requires the dishes to taste crisp and tender, and the color is green and bright. It is absolutely impossible to rely solely on the combination of heat source firepower and heating time. It is also necessary to consider whether the heat in the pot is high enough before the raw materials are put into the pot. No matter how much firepower (within the possible range of cooking), short-time heating or appropriate extension of heating time, it is difficult to achieve the expected effect when discharging. It can be seen that without the element of thermal medium temperature, it is difficult to make it a temperature. When microwave heating, the factor is no longer the temperature of the heating medium, but the amount of electron energy carried by the microwave. This is just a special case.
3. Heating time. That is, the long-term effect of heat energy or other energy on raw materials in the cooking process has long been valued by people. The temperature of the heat medium can determine the heat flow between the heat medium and the raw material, but it cannot determine the heat absorbed by the raw material. The heating time is matched with the temperature of the heat medium.
The three elements of heat source firepower, heat medium temperature and heating time always interact and coordinate with each other in thermal power. Changing any of these factors will have a great influence on the efficiency of heat.
Fourth, the control of temperature.
(A) to grasp the meaning of temperature
When a certain heat medium is used to heat raw materials, according to the quality requirements of dishes, the combination form of heat source firepower, heat medium temperature and heating time is determined by comprehensively considering various influencing factors of heat duration. This is to master the temperature.
When learning how to master the cooking temperature, you must follow the following basic principles:
1, taking the food quality requirements as the criterion.
The quality requirements of dishes are sometimes called cooking requirements. Different dishes have different specific requirements. But three are basic, that is: safe to eat, reasonable in nutrition, palatable and beautiful. Meeting these three basic requirements of dishes is the first principle of mastering cooking. That is to say, the combination of the three elements of heat must ensure thorough sterilization, mature raw materials, no harmful substances and less nutritional loss, and at the same time ensure that the dishes are delicious in texture, fresh and pure in color, rich in aroma, full in taste and perfect in shape.
2. According to the characteristics of raw materials
Cooking pays attention to the art of materials, including mastering the temperature according to the characteristics of raw materials. In the process of cooking, the combination of three elements of cooking temperature must be based on the quality requirements of dishes and the nature and form of raw materials. Generally speaking, raw materials with old quality or large shape are heated in the form of low heat source firepower, low heat medium temperature and long heating time, while raw materials with tender quality or small shape are heated in the form of high heat source firepower, high heat medium temperature and short heating time. This is only the most general rule, and we should pay attention to the differences of various raw materials in actual operation.
3. Be flexible.
Although mastering cooking must follow the two basic principles of taking the quality requirements of dishes as the criterion and the characteristics of raw materials as the basis, under the general principle, it should also be flexible, strict but not dead, alive but not chaotic. Because the application of temperature is affected by many factors, and in different situations, the degree of influence of various factors is different. In addition, different regions and ethnic groups have different dietary customs, and the requirements for the temperature of dishes are also different. For example, Guangdong people pay attention to fresh vegetables, while northwest people don't eat crisp cattle and sheep. These all need to change the conventional fire form slightly when mastering fire to adapt to various possible changes. But be strict and not die, and at the same time pay attention to living without chaos. In other words, under the premise of not violating the objective change law of raw materials, the quality requirements of dishes can still be achieved through flexibility.
In the specific operation of mastering the cooking temperature, it is very important to understand the physical and chemical changes in raw materials and their relationship with the quality of dishes through the surface changes of raw materials during heating. Most of the physical and chemical changes that occur when raw materials are heated will be reflected by the changes in the shape and color of raw materials. These changes are caused by the absorption of a certain amount of heat by raw materials in a certain period of time. Judging from the exterior and interior is an effective means to master the temperature in cooking. If you want to skillfully use this method, you must understand the changing law of various raw materials under various heating conditions and accumulate practical experience in burning, watching water and using fire.
(2) Factors affecting temperature
It is very necessary to master and use temperature and understand its influencing factors. There are many factors that affect the temperature, including the nature of raw materials, the amount of heat medium, the amount of raw materials, seasonal changes and so on. They affect one or several elements of temperature, thus limiting the composition of temperature.
1, the influence of raw material properties
The characteristics of raw materials refer to the nature and shape of raw materials. The so-called attributes include hardness, density, maturity and freshness of raw materials. Different raw materials, due to their different chemical composition and structure, will bring about differences in performance. The same raw materials have different growth (or feeding) time, harvesting (or fishing and slaughtering) time and storage period. , it will also bring about differences in nature. These differences in properties will inevitably lead to differences in thermal conductivity and heat resistance of raw materials. Therefore, under the premise of meeting the cooking requirements, we must choose the heat transfer medium and cooking temperature according to the properties of raw materials.
The so-called shape includes the size of raw materials, the thickness of blocks and so on. Generally speaking, under the condition that the nature of the raw materials needed for cooking is certain, people with large and thick bodies need to absorb more calories when they change moderately, while people with small and thin bodies need to absorb less calories. This point can not be ignored in the application of heat.
Because the properties of raw materials have a great influence on the application of heat. When cooking dishes composed of various raw materials, the distribution order should be arranged reasonably according to the different properties and forms of various raw materials to meet the different cooking requirements of various raw materials.
2, the influence of heat medium dosage
The amount of heat medium is related to the capacity of heat medium, and the capacity of heat medium has certain influence on the temperature of heat medium. When the consumption of a certain type of heat medium is large, more heat needs to be obtained from the heat source to reach a certain temperature, that is, the heat capacity of the heat medium is large. At this time, the temperature stability of the heat medium is good, and a small amount of raw materials will not cause significant changes in temperature. When the dosage is small, the heat source can reach the same high temperature by transferring less heat. At this time, the heat capacity of the heat medium is small, and the temperature will drop sharply with the input of raw materials. To maintain a certain cooking temperature, it is necessary to increase the heat source firepower appropriately. It can be seen that the amount of heat medium will affect the temperature stability of heat medium. Thereby changing the combination form of fire elements.
3, the influence of raw material consumption
The input of raw materials affects the temperature of heat medium. When a certain raw material is cooked into a certain dish, it needs to be heated at a certain temperature for a long time. After the raw material is input, it will absorb heat from the heat transfer medium, which will lead to the temperature reduction of the heat transfer medium. To maintain a certain temperature, there must be a large enough heat source to match the firepower. As soon as there is trouble, the temperature will drop, and only by extending the heating time can the raw materials mature. The amount of raw material input has different effects. If the investment is large, the impact will be great, and if the investment is small, the impact will be small.
When it comes to the influence of raw material consumption on the temperature of heat medium, the ratio of raw material consumption to heat medium consumption needs to be considered. The influence of heat medium dosage on the temperature of hot coal is just the opposite to that of raw materials. So the influence of some raw materials can be offset by increasing the amount of heat medium. In cooking practice, it is generally required to keep a certain proportion between some cooking methods.
4, the influence of seasonal changes
There is a big contrast between winter and summer all year round, and the ambient temperature generally differs by tens of degrees Celsius. This will inevitably affect the cooking temperature. When the temperature is low in winter, part of the energy released by the heat source will be reduced, and the heat carried by the heat medium will be lost in the environment. When the temperature is high in summer, the heat released by the heat source and the heat carried by the heat medium are much less than in winter. Therefore, when cooking the same dish with the same quantity, it is necessary to appropriately increase the heat source firepower, increase the temperature of the heat medium or extend the heating time in winter, and appropriately weaken the heat source firepower, reduce the temperature of the heat medium or shorten the heating time in summer. Although the seasonal change has little effect on the temperature, it can't be ignored.
In addition to the above factors, there are also the properties of heat medium, heat source, cooker performance and kitchen environment. This also has a certain influence on the temperature. The nature of the heat source, the performance of the cooker and the kitchen environment can be regarded as constant factors in a certain cooking environment, and their influence is only considered in the kitchen design.