Production of potato jam

Frozen spinach can be divided into two types: ordinary frozen storage and ventilated cold storage.

(1) the ordinary frozen storage method chooses a shady and dry place, sets up a shade barrier along the east-west direction, and digs one or more ditches in the shade area on the north side of the barrier. Its specifications vary according to the local climatic conditions. In Beijing, the ditch depth is about 15 cm, and the width is generally about 30 cm depending on the size and number of spinach placed. Then lay a layer of fine sand at the bottom of the ditch. When the temperature is stable below 0 ℃, the spinach is bundled into a bundle. Then cover a layer of fine sand, with the cold weather, cover soil by stages, the thickness and times of soil cover are determined according to the local climatic conditions, Beijing area is divided into 2 to 3 times, the total thickness is 170cm, in the cold season can be covered with grass grass, to ensure that the temperature in the ditch is-6 ℃ 8 cm, so that the leaves freeze, but the roots do not freeze.

(2) the ventilation ditch frozen storage method is basically the same as the ordinary frozen storage method, the difference is that the ditch is 1215cm deep and 100cm 200cm wide, dig 2 to 3 ventilation ducts with a depth of 2cm and a width of 20cm along the direction of the ditch, and frame a single layer of straw on the ventilation duct, on which spinach is covered with a thin layer, and then covered by stages, and the soil covering method is the same as the common frozen storage method. The ventilation duct in the ditch exposed to the ground, should be open at the initial stage to facilitate cooling, so that spinach frozen, and then gradually blocked with the cold weather. After the beginning of spring, the ground temperature rises, and then gradually remove the straw handle from the ventilation duct.

The frozen spinach comes out of the ditch before it is put on the market, put it in the vegetable cellar or the room slightly higher than 0 ℃, thaw naturally for 3 to 5 days, fully recover, and then arrange and sell.