First, clean the sweet potatoes one by one, then crush them with a machine, then rinse and filter them with water, and after many times of precipitation, clean sweet potato powder can be obtained. After that, there are many processes such as boiling, powder leakage and drying. Every year, when making sweet potato vermicelli at home, the whole family comes to help. Last year, nearly 400 sweet potato vermicelli were made, and the family was busy for a week. It is said that the cost of sweet potato powder is five or six yuan a catty, which is actually a bit low.

Here, let's calculate the cost first. The flour yield of the sweet potatoes we grow here is close to 20%. Generally, it takes six or seven kilograms of sweet potatoes to produce 1 kilogram of sweet potato flour. And a catty of sweet potato powder is definitely not a catty of vermicelli. Even if it is calculated by 100%. The price of a kilo of sweet potato in our local area will be 70 cents to 80 cents, so the cost of sweet potato alone will be more than that of 4 yuan, which is not to mention the loss, machine cost, electricity cost, labor cost, etc., so the cost of sweet potato vermicelli is at least more than that of 6 yuan.

There are two main reasons for this. They minimize the cost. One is the material. In fact, the main material of the sweet potato vermicelli in the supermarket is cassava flour with a small amount of sweet potato flour, which is why these vermicelli are not resistant to cooking, not smooth, and not bright or smooth when cooked. Another reason is that the sweet potato vermicelli in supermarkets are generally produced in batches by mechanization, which greatly reduces the production cost. In addition, the sweet potato powder sold in the supermarket, like the sweet potato vermicelli made by farmers, is unpacked, further reducing the cost. As a result, the cost of sweet potato vermicelli in these supermarkets is around 2 yuan's money, so they buy three yuan a catty, in fact, the profit is relatively high.