Why use cold water instead of hot water when thawing pears

Do not use hot water because frozen meat, frozen pears.

The iso temperature is at 0 degrees Celsius.

Below, if it is thawed in hot water, the frozen meat absorbs heat from the hot water, and its outer layer quickly thaws and the temperature quickly rises to more than 0 degrees Celsius, and there is a gap between the meat layers, and the ability to transfer heat is reduced, so that the frozen meat inside is not easy to absorb heat and thaw and form a hard core.

Use cold water: If the frozen meat is placed in cold water, the temperature of the cold water will quickly drop to 0 degrees Celsius and part of the water will freeze due to the heat absorption of frozen meat and frozen chicken, because 1 gram of water can release 80 calories of ice, and 1 gram of water can be reduced by 1 degree Celsius and only release 1 calorie of heat, so much heat is absorbed by the frozen meat, so that the temperature of the outer layer of the meat rises quickly, and the inner layer is easy to absorb heat, and the temperature of the whole meat rises to 0 degrees Celsius quickly, so repeated several times, the frozen meat can be thawed.

When the frozen food is placed in cold water, because the temperature of the food is lower than the water, the food absorbs heat, the water releases heat, and the cold water turns itself into ice due to the release of heat, when the thickness of the ice no longer increases, it means that the food and water have reached 0, and the food has dissolved; If soaked in hot water, hot water can easily cook the surface of the food, and the hot surface is a poor conductor of heat, and it is not easy to transfer heat, so hot water cannot be used

The smaller the temperature difference between cold water and frozen pears, the more heat exchange will take place. It can be thoroughly dissolved inside and out.

If you use hot water to thaw pears, because the temperature difference between hot water and frozen pears is too large, the outer layer of frozen pears is often scalded and soft, and a frozen core is retained inside. It is not easy to dissolve.

Frozen pears are bound to be a must-have fruit in winter for friends in the north, but for southerners, they are very fresh, so when frozen pears are thawed, should they be defrosted with hot or cold water? Can frozen pears be thawed with hot water?

Defrost frozen pears with hot or cold water.

Cold water is recommended. Because the temperature of frozen pears is below 0 degrees Celsius, if they are thawed in hot water, the outer layer of ice will quickly dissolve and reach a temperature of more than 0 degrees Celsius, but the internal ice has not yet thawed, so a temperature difference will form between the inner and outer sides, resulting in a decrease in the heat transfer rate. Therefore, it is generally defrosted with cold water to thaw frozen pears, so that the outside and inside of frozen pears can be slowly thawed together with the increase in temperature, and the taste will be better.

Can frozen pears be thawed with hot water.

Not recommended. If you put the frozen pear in hot water to thaw, because the temperature of the frozen pear is below 0, then the ice cubes on the outer layer will be quickly thawed by the hot water, but at this time, the ice cubes in the frozen pears have not been melted, and if you eat them, you will not be able to bite inside. If you continue to soak until the ice cubes melt, the outer layer will be blanched, so it will not taste good, so it is not recommended to soak frozen pears in hot water.

Why are frozen pears thawed faster with cold water.

When the frozen pear is placed in cold water, because the temperature of the frozen pear is lower than the water, it will absorb the heat in the water, and the cold water will automatically freeze on the surface of the frozen pear after releasing the heat, when the thickness of the ice no longer increases, it proves that the temperature of the frozen pear and the water has reached 0 at this time, then the frozen pear will be thawed at this time. In the case of hot water thawing, the outer layer of the frozen pear is a poor conductor of heat energy transfer, so the heat transfer rate is reduced, which will prolong the thawing time of the frozen pear.

How long should frozen pears be soaked in cold water.

The thawing time of frozen pears is uncertain, when thawing, they need to be soaked in cold water, and after a layer of ice has formed on the surface of frozen pears, they can be taken out to take out the shell and eat, generally speaking, it can be soaked for about 30 minutes. This is because the moisture of frozen pears is sugary, so its melting point is below zero, and when the temperature around frozen pears is below zero, the surface will freeze, but in fact, the inside has been thawed, so the ice can be eaten after crushing.

Soak frozen pears in cold water. If you thaw frozen pears with hot water, the scalded outer layer is a poor conductor of heat energy transfer, which leads to a decrease in the heat transfer rate, which will prolong the thawing time of frozen pears. Therefore, it is generally defrosted with cold water to thaw frozen pears, so that the outside and inside of frozen pears can be slowly thawed with the increase in temperature, and the taste will be better.

Soak the frozen pears in cold water. If you thaw frozen pears with hot water, the scalded outer layer is a poor conductor of heat energy transfer, which leads to a decrease in the heat transfer rate, which will prolong the thawing time of frozen pears. Therefore, it is generally necessary to thaw frozen pears with cold water, so that the outside and inside of the frozen pears can be slowly thawed together with the increase of temperature, and the taste will be better.

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We are glad to provide you with an answer: the state and phenomenon of cold water frozen pears are as follows: the temperature of frozen pears is below zero, and the temperature of cold water is above 0, so if you put frozen pears into cold water to soak, frozen pears and water can continue to exchange heat, so that their own freezing point is converted into water, then when the surface of the pear is covered with a thick layer of ice shell, it proves that the thawing has been completed, and the ice shell can be eaten after being crushed.

It should be noted that frozen pears cannot be soaked in hot water, otherwise the outer layer of frozen pears will be thawed, but the inner layer is still hard. Hope the above can help you <

Cold water has good heat transfer and fast thawing There is a formula in heat transfer that calculates the relationship between temperature difference and heat transfer rate and the "thermal stable state".

The "thermostable state" is the temperature of the object when it is no longer absorbing or dissipating

But the formula involves the knowledge of calculus, so I won't take it out here.

However, the formula can be explained in layman's terms.

Suppose there is a cube object, take two faces that are directly opposite each other, such as the top and bottom of an iron block, and analyze them.

First of all, there is a clear premise:

The medium is heated as the heat is conducted in the medium.

Assuming that the top surface is a high temperature area, the temperature is controlled at 100 degrees; The bottom surface is a low temperature zone, 60 degrees Celsius.

The average temperature of this iron block must be somewhere between 60 and 100.

And the temperature of each independent plane is different.

The scientist's measurement results show that the temperature of the measurement point varies depending on the location of the measurement point.

In other words, we can draw a function curve, the variable is the distance from the plane where the point is located to the top surface (the bottom surface, the two are the same), and the function value is the temperature of the plane.

And this function image is not a straight line, it is a curve. The meaning of the graph line is that the closer to the top surface, the slower the temperature drops; The closer you get to the bottom, the slower the temperature rises.

For different top and bottom temperatures, as well as for different materials, we can draw different images.

Based on the experimental data, the following conclusion is obtained:

The better the thermal conductivity of the substance, the more the temperature-distance image from the lowest temperature plane to the highest temperature plane will resemble a straight line; The worse the thermal conductivity, the more the image resembles an English letter"s"。

The smaller the temperature difference in the high and low temperature regions, the more the temperature-distance image from the lowest temperature plane to the highest temperature plane will be like a straight line. The greater the temperature difference between high and low temperatures, the more the image resembles an English letter"s"。

The thermal conductivity of tofu is definitely very poor.

Suppose there are two pieces of frozen tofu in a container with water all around. A soaked in hot water (60 degrees) and B soaked in cold water. (5 degrees.)

The high temperature zone in our ideal experiment is the six outer surfaces of the tofu, and the low temperature zone is the geometric center of the tofu.

A conclusion I gave above can be made for both pieces of tofu"s"shape image.

We should pay attention to the fact that the temperature difference between the high and low temperature of a tofu is large, so there is a place near the center area where the temperature is close to the lowest point and it is difficult to heat up, and this piece is not melted at all in actual life, and it is still frozen; B tofu also has such an area, but due to the small temperature difference between high and low temperature areas, the internal temperature of tofu is basically uniform (the graph is similar to a straight line), so there will be no embarrassing phenomenon that the outside is thawed and the inside is still frozen.

Since A tofu is not completely thawed after all, it is natural that B tofu with cold water is eaten by us first. Hahahaha!

As for the frozen pears in the Northeast, thaw them with ice water; When people suffer from frostbite, don't bake the fire, don't use hot compresses, but use cold water to heal the injury, all of which are the same truth.

Because the temperature of frozen meat and frozen pears is below 0, if it is thawed in hot water, the frozen meat absorbs heat from the hot water, and its outer layer is quickly thawed and the temperature rises to more than 0, and there is a gap between the meat layers, and the ability to transfer heat is also reduced, so that the frozen meat inside is not easy to absorb heat and thaw and form a hard core.

If the frozen meat is placed in cold water, the cold water temperature will quickly drop to 0 due to the heat absorption of the frozen meat and frozen chicken, and some of the water will freeze. Because 1 gram of water freezes into ice, 80 calories can be released (and 1 gram of water is reduced by 1 calorie only), so much heat is absorbed by the frozen meat, so that the temperature of the outer layer of the meat rises quickly, and the inner layer is easy to absorb heat, so that the temperature of the whole meat rises to 0 quickly. This is repeated several times for the frozen meat to be thawed.

From a nutritional point of view, this method of uniform and slow heating is also scientific.

However, it is not recommended to thaw with water. The most suitable method is to use two metal containers to put the thawed product in contact with the flat surface (basin floor) and let it stand in the air, quickly and without destroying the internal cell tissue.

This is because during the quick-freezing process of meat food, its intracellular fluid and extracellular fluid are quickly frozen into ice, forming crystals between meat fibers and cells. The crystals of this juice are one of the most valuable proteins and delicious substances. If thawed with hot water, not only will it lose part of its protein and its aroma, but more importantly, it will form a strong carcinogen called propionaldehyde.

Therefore, frozen meat must be thawed with cold water or allowed to dissolve slowly and naturally.