First, material selection

We should choose high-quality pollution-free soybeans without heat treatment, and the new soybeans with bright color, full seeds and no moth and mouse bites are better. The newly harvested soybeans are not suitable for use and should be stored for 3 months before use.

Note: The soaking time of soybean is related to the season.

Water quantity: the soaking volume is generally 2-2.5 times of the soybean volume, and it is best not to add enough soaking water at one time. For the first time, it is appropriate to soak the material surface 15cm. When the soaking water level drops to 5-7cm below the material level. That is, the soaked soybean meets the following requirements: the water absorption of soybean is about 120%, and the weight gain of soybean is 1.5- 1.8 times. The surface of soybean is smooth, without wrinkled skin, the skin of soybean does not fall off easily, and it feels loose when touched by hand. The inner surface of watercress collapses slightly, and it is easy to break with fingers, and the section is not hard.

Second, refining

The purpose of pulping is to extract protein from soaked soybeans to the maximum extent, and it is important to master the thickness of soybean milk. Too thick will affect the over-pulping rate, while too fine fiber will enter the bean dregs with protein, which will on the one hand cause the screen to be blocked and affect the filtration, and on the other hand, make the bean quality rough and the color dark. When grinding, we should also pay attention to adjusting the gap between grinding wheels, and add appropriate amount of water while grinding.

Third, boiling pulp

The boiling temperature should be controlled above 97 degrees Celsius for about 3 minutes, 3% defoamer should be added, and the heating should be uniform. When the temperature of the slurry reaches 75 degrees Celsius, the slurry can be ordered.

Fourth, order the pulp

Common coagulants

1, gypsum

The chemical name of gypsum is calcium sulfate (CaSO4), and it is appropriate to use gypsum powder on the market to paste. Generally, 5KG of soybean requires about 0. 15-0.2kg of gypsum powder. Add 400g of water to mix and evenly pour in soybean milk, and stir quickly. Stop stirring when beancurd flowers appear.

2. Brine

Using brine as coagulant, protein has a fast solidification speed, so it is not easy to master the operation. Take 5kg of dried beans as an example. Before discharging the slurry, sprinkle about 60g of salt on the bottom of the pulp barrel. When the temperature drops to 85 degrees Celsius, pour the soaked brine in 2-3 times. The amount of brine is 50-70g, and 50g of dried brine slices are soaked in warm water. Add a little tofu (about 35g).

3. Gluconic acid-lactone

The substance is a white crystal, which is easily soluble in water. The dosage is generally 0.25-%0.5% of soybean milk. Before ordering the slurry, the temperature of the hot slurry above 90 degrees Celsius is reduced to 75-85 degrees Celsius, and then the coagulant is added.

Five, powder brain

Put the bean curd into the brain barrel, clean up the sundries on the wrapped cloth, install the wrapped cloth on the workbench, then turn on the power switch and turn on the powder curd switch. (The voltage cannot be lower than 220V)

Sixth, suppression

Put the bean brain receiving tray on the first layer of cloth, open the meningitis valve, start the operation, and adjust the rolling gap to make the thickness uniform. After the first batch of wrapping cloth is connected, close the meningitis mouth and move the wrapped cloth after meningitis to the manual hydraulic press (at this time, the second batch of wrapping cloth can be installed to continue the meningitis work), press the pressure bar of the hydraulic press to the third to fourth pressure, then stop the flow for 3-5 minutes, and lift the manual hydraulic mechanism to expose the finished product. The bean skin produced by using it is not only hygienic, but also delicious, well-preserved in texture and even in thickness.

Note: Wash the wrapped cloth with clean water after use, and take it to the chartered flight for wrapping. The wrapped cloth should not be too tight or too loose. Gently step on the lower pedal for wrapping, and remember to turn off the power switch after wrapping (this step uses Yuxing tofu skin machine).

Then it is to save the tofu skin. As long as you follow the above steps, you can keep tofu skin for 4-6 days without adding any preservatives. Of course, you still need to buy a refrigerator at home. Because our fresh-keeping mode is in the refrigerator.

After peeling, the tofu skin should be cooled on a bamboo pole before storage! Put the cold bean curd skin in neat yards, then put it in disposable food bags and put it in the refrigerator for fresh-keeping mode. The fresh-keeping temperature is: 5- 15℃, below which tofu skin is easy to freeze, above which tofu skin is easy to deteriorate and rot, and the storage period of tofu skin in such an environment can definitely reach 4-6 days ~