Because the scale of sweet potato cultivation was relatively large at that time, not only people had to eat it, but also livestock had to eat it, and a large part of sweet potatoes were also processed into agricultural and sideline products for sale, such as sweet potato powder and sweet potato vermicelli. Now there are few races of sweet potatoes in the village, and fewer people make sweet potato vermicelli every year. Farmers' families make some every year. More than 200 kilograms of sweet potato vermicelli were made the year before last, and nearly 400 kilograms were made last year. These basically didn't sell in the market, all of them were 12 yuan a catty, so the villagers' relatives and friends bought them.

Making sweet potato powder is very complicated, and its main raw material is sweet potato. First, clean the sweet potatoes one by one, then crush them by 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 we make 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 yield of the sweet potato grown here is close to 20%. General production of 1 kg sweet potato powder requires six or seven kilograms of sweet potatoes. And a catty of sweet potato powder is definitely not a catty of vermicelli. Even if it is 100% calculation. The price of a catty of sweet potato in our local area will be 70 to 80 cents, so the cost of sweet potato alone will be more than 4 yuan, not counting the loss, machine cost, electricity cost, labor cost and so on. So the cost of sweet potato vermicelli is at least more than 6 yuan. Then why are the sweet potato vermicelli in the supermarket so cheap?

In fact, there are two main reasons. They cut costs to a minimum. One is the material. In fact, the main material of sweet potato vermicelli in the supermarket is cassava flour and 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 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 about 2 yuan, so buying 3 yuan a catty is actually more profitable.