In the middle of winter, what can make you feel warm instantly? Is it an electric heater, a hot pot, or a hug?
For me, in the small restaurant across the street from my home, steaming vermicelli pots, claypot rice, and lean porridge are the most irreplaceable. After getting off work, I dragged my nose in, and saw a few gurgling casseroles on the fire, as if I had come to the warm Guangdong.
It can't be unpalatable
It's just that why is every casserole tied up with wire?
The boss said that if you don't tie them, you won't be able to drink this pot of porridge!
My baby sand
If we want to talk about a casserole, we have to rewind time a little bit - not much, just 10,000 years.
At that time, human beings already had socialized behaviors and the rudiments of agriculture, and various stone blades made hunting and cutting convenient. At this time, a clever man suggested that if there was a bowl, it would be much more elegant to eat.
Stone bowls are too difficult to make, wooden bowls love to be bad. It's easy to dry it with mud, but it's just to drink it and drink it into muddy soup. It was found that some of the clay pots that had been burned by fire would no longer melt into the water, and this was the original earthenware. Thus, the Neolithic Age came in great stride.
Earthenware is really good, but there are also many problems, such as being too dense. Although the water will not turn into muddy soup, you have to drink it quickly, and it will seep out after a while. So everyone used their brains to find the right clay and sinter it at a higher temperature, which is pottery. Pottery has greatly reduced water permeability and is relatively durable, which is very popular with ancient humans.
Soon, everyone rolled up, the material became more and more delicate, and the pots and bowls made in this way were very light and thin, and the feel was good, which was the most popular home good. This delicate pottery we call "clay pottery".
Songze culture unearthed clay pottery beans
Lao Xin was photographed at the Suzhou Museum
I don't have to say that clay pottery makes a bowl, but it's over when I make a pot. The heat conduction of clay is relatively slow, the expansion coefficient is large, the outside is hot, the inside is not hot, the outside is vigorously expanded, and the inside is dead and alive -
Quack, broken.
The picture comes from the screenshot of the variety show
There are also some more shoddy products, which seem to be less broken. When the ancients experimented, this was really the case! So they began to "drive backwards" and mix some gravel, clay residue, plant and wood ash, and so on into the delicate clay, and this was the "sand-filled pottery."
Nowadays, we can see through the microscope that the cracking of pottery does not happen overnight, but erupts from all over the place, with small cracks forming medium cracks, middle cracks forming large cracks, and finally completely sparse. The sand pottery is different, the small crack does not take a few steps, it encounters a sand grain or pore, and the crack can't go down, so you have to stop or turn a corner. In this way, small cracks are difficult to aggregate and intensify, and the proportion of appliances burned is much lower.
The casserole is the ancient sand pottery.
The representative of traditional sand pottery - Shanxi Pingding casserole
Fragile but really fragrant
Sand pottery is a good thing that the ancients found in their long-term life, and even if the metal pot appeared later, it is still the main force of cooking utensils.
You must know that before the Song Dynasty, the iron pot was an absolute luxury, and non-princes could not have it. Moreover, the early iron pots were pig iron, which was also prone to breaking. The casserole is cheap and sufficient, anyway, the ancients didn't have so much need for frying and stir-frying, even if there is an iron pot, who has so much oil!
The "bear pressure cooker" unearthed from the Han tomb in Mancheng
Once again, the casserole has fallen out of favor and is contemporary. Modern gas stoves can instantly heat the pot to hundreds or even 2,000 degrees, and even if sand is added, the casserole still can't stand such a rapid temperature change. Putting some room temperature water and soy sauce into a hot casserole is enough to make it collapse. It can't be helped, that's when someone came up with the idea of putting a wire hoop on a casserole.
Cantonese people call this craft "hoop pot", which is a technical job. This loop of wire should be both tight and even. Anyway, the casserole is always going from small cracks to large cracks, and what the hoop has to do is not to prevent it from cracking, but to prevent it from "disintegrating".
箍煲
Even if it is completely split in half, as long as the hoop is good enough, the casserole can still maintain the original and will not spoil the pot of ingredients. The cracks are "reinforced" with rice broth or egg whites, and they can even be used repeatedly.
The word hoop pot can also be expanded to interpersonal relationships - they are about to break up and block each other, and persuasion and persuasion can make do with each other again, which is called "hoop pot" in Cantonese. The Marriage Mediation Office is probably a professional pot.
A craftsman who specializes in hoop cooking
Image from: Xijiang Daily
You may ask, since there are so many problems with casseroles, and iron pots are so cheap, why don't they all use iron pots?
No rut, casserole cooking is really fragrant!
The picture comes from the Internet
The casserole conducts heat slowly, is not resistant to high temperatures, consumes fire, and loves to break, which is from our point of view. From an ingredient point of view, these are even advantages. For dishes such as stewing and stewing, metal cookware is not good at it - the temperature of the part of the fire below is particularly high, and the ingredients are tormented, but the wall of the pot that does not get on the fire is equivalent to a large heat sink, which quickly disperses the heat into the air, making the ingredients on it feel desolate. As a result, the flavor amino acids below have been decomposed, and the top ones have not yet been stewed.
The casserole can keep the heat in the pot uniform and stable for a long time, so that the meat and spices can give full play to their strength.
The pan gas overflowed the screen
Technology changes casseroles
After talking about it for a long time, it seems that there is no popular science. Don't worry, the dry goods are coming.
The above content is not difficult to understand, but have you ever thought to the root - why clay loves to expand so much when heated, and why is the mud pot before firing so different from the mud pot after firing?
Clay pot for side stoves
Pottery is made of clay, and the source of clay is many and complex, and it is generally clay composed of oxides of silicon and aluminum, and there are many crystals inside. During the high-temperature firing process, a part of the material is dissolved, recrystallized or vitrified. While the things are still those things, and the elements are still those elements, the structure has changed. Just like charcoal can cause diamonds under high temperature and pressure.
Some crystals in kaolin
These crystals have different crystal forms, different arrangements, and different coefficients of expansion, which causes them to change differently when heated.
For example, quartz is the most abundant crystal in china clay and the most varied. Sand, crystal, and agate are all quartz, high-temperature quartz, low-temperature quartz, cristobalite quartz, and kequartz...... The various crystals of quartz have completely different physical properties, and the coefficient of thermal expansion of cristobalite is much greater than that of high-temperature quartz.
Crystal crystals
With this modern knowledge, there is no need to blindly touch the elephant to make a casserole. For example, adding spodumene and other ores containing lithium oxide to the original soil can greatly reduce the highly expanded crystals in the porcelain clay, and make a heat-resistant casserole that is not afraid of dry firing. This pot will not crack if thrown directly into the water from a dry 800-degree fire.
Many of our new casseroles today are labeled "Add spodumene imported from Africa", which is this kind of product. In fact, the so-called African spodumene is not very rare, and such a casserole is not much more money.
A very artistic-looking spodumene
Of course, you should also pay attention to the use of casseroles at home, such as trying to avoid dry boiling over high heat, avoiding cold water hitting the hot pot or placing the hot pot directly on the cold tiles, etc.
If you love cooking, why don't you buy a casserole to cook quickly and warm up all winter?