#我来唠家常#
▲ Hairy crabs. Photo/Visual China
-The Legend of the Gentleman of Things-
Crab is delicious
Everybody loves
Infernal north and south
No distinction between elegance and vulgarity
▲ The article is reprinted from China National Geographic BOOK, ID: CNGBOOK360
Ouyang Xiu said, "It's the time when the new autumn crabs are fat", autumn is here, and it's the season to eat crabs again.
There are more than 800 species in mainland China alone, and the most popular of them is hairy crabs.
Today we are going to chat, why hairy crabs?
River crab river crab
Hairy crab, the scientific name of the Chinese mitten crab (Eriocheir sinensis), is also commonly known as "river crab".
The secret of deliciousness is hidden in this "river" word.
▲ The characteristic of hairy crabs in ancient books is the big hairy pincers, "mitten crab", which means crabs with fluffy hairs on their chelicerae. The fluff is a bit like a beard and grows a little more each time it molts. The fluff on the male crab's chelicerae is more developed, and the function has not yet been clarified, and some scholars speculate that it probably has a tactile function. Illustrated by Zheng Qiuyang, Picture by "Notes on the Mistake of the Sea, III"
It is generally believed that there are four kinds of mitten crabs in the world, but the Chinese mitten crab (hairy crab) is the largest and has the most meat.
▲The difference between the dorsal armor of the four types of mitten crabs in the world. They are Chinese mitten crab, Japanese mitten crab, Taiwan mitten crab, and narrow mitten crab. Illustrated by Zheng Qiuyang, Picture by "Notes on the Mistake of the Sea, III"
Hairy crabs live in rivers, and there are often natural or artificial ditches between them, and hairy crabs spread with the help of these rivers. With the Yangtze River and the Huai River as the center, the Pearl River in the south, and the Yalu River in the north, there are hairy crabs.
▲ Japanese mitten crab in "Plum Garden". Painted / Maori Plum Garden
Liang Shiqiu said, "Crab is delicious, everyone loves it, there is no north and south, regardless of elegance and vulgarity." ”
▲ The distribution of hairy crabs in China. Cartography/monk
Hairy crabs live underwater and are larger than their body length, so it is more convenient to walk sideways. When they crawl, one foot is bent and the other is stretched outward, and after grasping the ground with their fingertips, the bent foot immediately pushes the body to the other side.
▲ The muscles of hairy crabs contract quickly and powerfully, and with the sharp knuckles at the front end, it can even climb vertically, so hairy crabs often "escape" accidents. Photo/Visual China
To survive in the river, the rampant hairy crab has developed a well-developed muscle, and the meat is very elastic. The meat is rich in umami substances such as alanine and glycine, and as a crustacean, the muscles of hairy crabs are only striated muscles, and the meat is delicate and has strong water holding capacity. Compared with the compatriots living in the sea, hairy crabs are a little less salty and a little more sweet.
The autumn wind rises, and the crab feet itch
"Sea crabs eat meat, river crabs eat yellow", the hairy crab is the most worthy of mentioning, or the crab roe; "nine females and ten males", especially in September and October of the lunar calendar, the most delicious. And this has to start from 50 million years ago.
Hairy crabs belong to the family of square crabs, and according to the available fossils, their ancestors appeared 50 million years ago, when crabs inhabited the ocean for life.
By the time of the Quaternary Period, the earth entered the glacial and interglacial periods, and there were several cyclic alternating changes such as sea invasion and sea retreat, and the rise and fall of the earth's crust. However, the larvae can still only live in the shallow waters of brackish water estuaries, so the adults must return to the shallow sea to breed.
▲ The Chinese mitten crab in the North Rhine River in Germany, the light-colored hair on the cone indicates that it has just shed its shell. The Chinese mitten crab is a local invasive species. Picture/"Sea Mistake Diagram Notes III"
In nature, reproduction and reproduction are top priorities. In order to migrate long distances and breed offspring, hairy crabs are well prepared.
The ancient name of the crab is "no intestine", in fact, the hairy crab has intestines, but it is very small, Xu is to make up for this defect, the crab has grown a developed midgut gland. The midgut gland is the famous "crab roe", which is equivalent to the liver of the crab and is the organ used by the crab to store nutrients and absorb nutrients, so it is also called the hepatopancreas.
Just like foie gras, most of the "crab roe" is stored in lipids, and it is very fatty. Both male and female crabs have hepatopancreas and begin to store energy in the summer in preparation for the next offspring.
▲ Crab roe and crab paste. Photo/Visual China
"The autumn wind sounds, the crab feet itch", the time of breeding of hairy crabs is the turn of autumn and winter, and the water temperature drops. The lower water temperature is a signal to the hairy crabs, which begin to develop gonads, gather in groups, and migrate down the river to the estuary to have offspring. As the folk saying goes, "If the water is not cold enough, the crab will not be delicious", and it is precisely for this reason.
When eating female crabs, if you look closely, you will find two kinds of "crab roe": one is yellow and has a softer texture, and the other is a hard lump with a reddish orange color. The former is also known as the hepatopancreas of male crabs, which is commonly known as "crab roe", and the latter is also known as "red paste", which is actually the gonads of female crabs, that is, the ovaries.
▲ The internal structure of the female crab. Cartography / West Lake Vinegar Fish
Female crabs have to shoulder the heavy responsibility of reproduction, and require more energy, and in the ninth month of the lunar calendar, the nutrients in the liver are slowly transferred to the gonads, and at this time, the two account for about half, which is the most delicious.
The gonads of male crabs are smaller, and the enlarged ones are mainly due to the development of accessory gonads and vas deferens, and when steamed, they are milky white gelatin, which is "white paste". Therefore, the development is slower than that of female crabs, and it is more delicious in the later lunar October.
▲ The internal structure of the male crab. Cartography / West Lake Vinegar Fish
It is said that "nine females and ten males" is this truth. After these two months, the gonads of hairy crabs will become overripe and degenerate, and their size will shrink.
There is also a time when you can also eat crabs, "June Yellow". The crab roe of hairy crabs is mainly used to provide energy for molting and gonad growth, and in June, before the gonads have developed, they can enjoy the fragrance of the liver and pancreas alone. In Jiangnan, hairy crabs have to go through about 20 molts in their lives to fully grow, and in June, they can often eat "double valve crabs", the outer layer is a hard shell, and there is a layer of soft shell that is not fully mature, which tastes unique.
▲ The hairy crab of "June Yellow" has a strong fishy smell and delicate meat, which is more suitable for spicy crabs. Photo/Visual China
How can it be?
Regarding how to pick crabs, "Naturalist" Zhang Chenliang introduced a good method, "top cover fat": the butt of the hairy crab, that is, the place where the lid is lifted, and there is a gap between the umbilicus below, the wider it is, the fatter it is, because there are so many crab roes that it is lifted up. According to him, this was "taught by someone who went to Hongze Lake as an undergraduate and raised hairy crabs, and this method still works, and I still use it." ”
▲ Hairy crabs. Photo/Visual China
In addition, you can also pay attention to the following points when picking crabs:
Color: Hairy crabs with blue back and white belly are best. Crabs are benthic organisms, and hairy crabs that live in waters with a good environment can grow green backs and white bellies.
Weight: Pinch the crab legs, the hard and plump ones are better, and the heavier ones of the same size mean the meat is fuller.
Vitality: The histidine in the body of a dead crab will be broken down into toxic histamine, so you can touch the crab's eyes, and it means that it is still alive.
▲ Hairy crabs in the sea mistake diagram. Illustrated by Nie Huang
Starting from the Liangzhu culture, the history of crab eating in China has been more than 4,000 years. Chinese, who are well versed in the way of cooking, advocate a simple way in the way of cooking crabs, steaming, which is the best way to eat crabs without losing the original taste. Zhou Zuoren said that there is no other good way to eat crab, just boiled and peeled the shell and dipped in ginger vinegar to eat.
Crab is the freshest in the world, but it is also a very "unpalatable" food, not only to carefully pick out the crab gills, crab stomach and crab heart and other parts that can not be eaten, there are two major problems: ugly to eat, unclean to eat.
▲ Hairy crabs. Photo/Visual China
Picky Jiangnan diners used the "Eight Pieces of Crab". Use round-headed scissors to cut off two large claws and eight crab legs one by one, gently knock the waist hammer around the crab shell, and then split the back shell and navel with a long-handled axe, and then take a drill, tweezers, fork, hammer, or pick or fork or knock, take out the golden buttery crab roe or milky white sticky crab paste, and take out the snow-white and tender crab meat.
▲ 蟹八件。 制图/西湖醋鱼
"Eight pieces of crabs" have been popular in Suzhou as early as the Ming Dynasty, and they are elegant items for the boudoir in the south of the Yangtze River, and even used gold and silver as a dowry.
Its original origin is no longer known, and it is likely that people gradually explored it in the practice of eating crabs; according to the need, the day before yesterday he made one, yesterday you made one, and today I made one, and slowly formed the "eight crabs". Today, the "eight pieces of crabs" are already common things, but to really use them, in fact, only scissors, crab claws, and crab needles are very sufficient.
▲ Hairy crabs. Photo/Visual China
Yuan Mei wrote in "Suiyuan Food List": "Crabs should be eaten alone, not with other things." It is best to cook it in a lightly salted soup and eat it yourself. ”
Do-it-yourself, it is indeed a lot of fun, and the Chinese eat crab tricks.
▲ Butterflies spelled out by hairy crabs. Picture/"Sea Mistake Diagram Notes III"
Zhang Chenliang researched an ancient "butterfly fighting" method in "Sea Mistake Diagram Note 3": breaking off the finger that the crab can move (movable forceps finger) will bring out two bone fragments, which are used to attach the muscles of open and closed forceps. The large one is called the "obturator medial process", and the small one is called the "open muscle medial process".
Put the two movable pliers fingers side by side, fingertips pointing down, one to the left and one to the right, press the wet fluff in the middle, the fluff is tangled with each other, and after drying, it becomes one and becomes a butterfly shape. The elongated open muscle protrusion is the antennae, the wide obturator muscle protrusion is the forewing, and the two fingertips on the back are the tail of the butterfly's hind wings.
Yangcheng Lake?
When it comes to hairy crabs, Yangcheng Lake always comes to mind. During the Republic of China, Zhang Taiyan's wife Tang Guoli personally stamped "It's not good for Yangcheng Lake crabs, why bother in Suzhou in this life".
The three famous crabs in ancient China, Shengfang Crab (native to Baiyangdian), Huajin Crab (native to Ancient Hongze Lake), Yangcheng Crab, only the hairy crab in Yangcheng Lake is the only one. Why Yangcheng Lake?
▲ The main production area of hairy crabs. Cartography/monk
Jiangnan, with gentle terrain, rivers and lakes, abundant aquatic plants and suitable temperature, has always been the main production area of hairy crabs. In fact, Yangcheng Lake was a piece of land before the Song Dynasty, and then it may have been formed due to the blockage of the Loujiang River and flooding.
Therefore, the bottom of the lake is shallow and flat, with an average water depth of only 1.9 meters, which is suitable for the growth of hairy crabs. If the water depth is too shallow, the sun will bask the crab to be precocious, and it is easy to grow small.
Yangcheng Lake is sunny and full of abundant aquatic plants, and slowly, fish, shrimp, snails and zooplankton also gather, which are the favorite and delicious food of hairy crabs.
▲ Fishing boats fishing on Yangcheng Lake. Photo/Visual China
Aquatic plants provide oxygen, purify water and are a great place for hairy crabs to take refuge. Hairy crabs are benthic organisms, all live at the bottom of the lake, crabs can "seclusion" in the grass to live, preying on small fish and shrimp in the meantime, the meat is fresh and tender, green back and white belly.
Yangcheng Lake is the closest grass-shaped lake to the mouth of the Yangtze River, and hairy crabs have "moved" here to settle down. In addition, it is not far from the mouth of the Yangtze River, and the salt content of the lake is high, so the hairy crab meat here is slightly salty, which can stimulate the sweetness of the crab.
▲ Crab farmers on Yangcheng Lake. Photo/Visual China
Therefore, the hairy crabs produced in Yangcheng Lake can be described as green back and white belly, yellow hair and golden claws, fat, fragrant and tender meat, jade fat red paste, and exceptionally delicious.
But a few decades ago, wild hairy crabs in the Yangtze estuary became scarce due to damming, water pollution, river remediation and climate change. Today, the ecology of rivers and seas has changed, and artificial breeding can only be transported instead of migratory.
After the 80s of the last century, the breeding technology of hairy crabs made a breakthrough, and crab farmers began to flock to raise crabs, resulting in the overload of Yangcheng Lake's capacity and the quality of crabs once seriously declined. Later, after scientific breeding, the production was reduced, and the aquatic weeds and small fish snails were replenished, and they were recovered.
▲ After the water quality and environment of Yangcheng Lake have improved in recent years, there are waterfowl inhabiting here. Photo/Visual China
To this day, hairy crabs in Yangcheng Lake are still in short supply. But it is not necessary to only stare at Yangcheng Lake, and Wang Wu, a professor at Shanghai Ocean University who has solved the problem of hairy crab breeding, said frankly, "The best hairy crabs are in East Taihu Lake, Shanghai, Anhui and even Taiwan, there are very good crabs." ”
Hairy crabs have become so popular in recent years that they can be easily eaten even in inland areas, in addition to the maturity of breeding technology and cold chain transportation, and the price drop is more acceptable to the public. There is also a very important reason behind it, hairy crabs can be particularly "carried".
Hairy crab is an amphibian crab that can actively regulate the osmotic pressure in the body, adapt to the external environment, and will not be dehydrated or swelled in freshwater, brackish water or seawater, and can even live out of the water for a short time. The "crab roe" of hairy crabs is well developed and full of nutrients, so it is very hungry and can survive without eating for dozens of days.
▲ Experimental observations show that hairy crabs can even live in the mud for more than 30 days. Photo/Visual China
The low temperature also reduces its metabolism, so it is not a problem to keep it in the refrigerator for a few days, but it is best to cover the hairy crab with a few clean wet rags when preserving it to keep it moist. Experiments have shown that hairy crabs can survive 6-9 days before dying even when exposed to air, and the main reason for death is that the crabs cannot breathe after the gills are dehydrated. Therefore, hairy crabs are often transported with a humidified cloth and a bottle of frozen water, which is also because of this reason.
▲ Crabs, moon cakes, and chrysanthemums have always been symbols of the Mid-Autumn Festival. Photo/Visual China
Now the hairy crabs are full of yellow fat, call your three or five friends, take out the prepared steamer, ginger, cooking wine, perilla, and, has accumulated a whole year's appetite, to a grand hairy crab feast.