1. Copper utensils are prone to patina. According to the requirements of health laws, parts in contact with food must be tin-plated.

2. The reason why tin is used is because of the metal tin The molecular structure is relatively stable, making the soup base in the hot pot less likely to have a metallic taste.

Extended information:

First appeared in the Western Han Dynasty. In November 2015, the earliest copper hotpot discovered in China was unearthed from the tomb of Haihunhou of the Western Han Dynasty in Datangping Township, Xinjian District, Nanchang, Jiangxi. ?

During the Three Kingdoms period, the so-called "five-cooked pot" appeared. A copper pot was divided into five compartments, each with a different flavor of soup for cooking different foods. It was spread throughout the streets. Xiaogang's Yuanyang Hot Pot has different approaches but the same purpose.

In the Southern and Northern Dynasties, a kind of copper hot pot appeared that was "large in mouth, wide in belly, thin and light, and easy to cook". This was a kind of copper hot pot used by the Liao people living in Sichuan and Hunan at that time. .

In the Tang Dynasty, there were already copper "hot pots". In 1984, a mural was unearthed in Aohan Banner in Chifeng City, Inner Mongolia (formerly "Zhaowuda League"), showing Khitan people sitting on the ground around a hot pot in a dome. According to expert research, this painting depicts Khitan people in the early Liao Dynasty. The scene of eating hotpot mutton.

Reference: Baidu Encyclopedia--Copper Hot Pot