Ice container

Ancient refrigerator [Photo/artron.net]

The most commonly used cooling utensil is called "Jian", which is a big container filled with ice. It was made of ceramic in early Chinese history, and was later made of copper. The "Jian" can be seen as an ancient refrigerator, which can be used to make cold drinks. Put the vessel holding food inside the "Jian", close the lid, and the drinks would become cold after a while.