It has a lot to do with local food customs.

Ningshao has a long history of being addicted to odor. There is a relevant record in "Yue Proverbs" written by Fan Xuan of the Qing Dynasty: "As seen in the Yi Fu Gua, the stalks are like sugarcane segments. The smell of pickling is good, and it is best eaten with rice." Zhejiang faces the sea to the east and has a humid climate, especially in the During the rainy season, food is most likely to become moldy. In order to facilitate storage, smart people used various methods to pickle food. Over time, they developed perfect fermentation technology.

Food that smells bad but tastes delicious is actually related to the structure of the human body. The odor molecules of the food diffuse from the mouth to the back of the nasal cavity, and the brain’s perception of this is different from smelling it directly with the nose. What arrived was completely different. During the pickling process, microorganisms in the brine break down proteins and convert them into amino acids, which are the main substances that make up the umami flavor. Therefore, the smell and umami of "stinky vegetables" have the same origin.

What are Ningbo’s three odors?

Ningbo’s three odors are traditional famous dishes in Ningbo, Zhejiang. They refer to stinky winter melon, stinky amaranth tubes, and stinky cabbage hearts (stinky taro and yam). The biggest characteristic is the smell. It smells bad, but tastes delicious. Marinate tofu, cabbage sum, and zucchini in stinky vegetable juice, pour in fresh rapeseed oil, steam and serve. It's loose, fragrant and waxy, the cabbage heart is emerald green, salty and not greasy.

The key to making stinky brine is to seal it, otherwise the stinky smell is the favorite place for flies to breed their offspring. Good stinky brine is not only clear but also has a peculiar smell. It can be used for several years if kept well. In rural areas, there are many home-grown vegetables, such as winter melon, amaranth, taro, wild rice, etc., which can be used as "stinky" objects.

The above content refers to Baidu Encyclopedia-Ningbo Three Odors