Why is Guangdong old tofu sold by the catty?

Guangdong's old tofu is sold by the catty, because pricing by weight is a common sales method and one of the traditional food sales methods. Old tofu is sold by the catty, which can ensure that consumers can buy the required quantity according to the demand and pay the corresponding fees according to the actual weight. Old tofu is a kind of food with tofu as the main raw material. Tofu itself is made of soybean after processing, and the weight of tofu will vary with the water content. Therefore, selling old tofu by weight can more accurately reflect the value of goods and ensure fair trade.