Make full use of grape resources and diversify your products to meet the market. Grapes can be processed into preserved fruits, juices, fruit wines and other products.
1. Processing of raisins
(1) Select seedless varieties with high solids content, good flavor color, not serious enzyme browning, suitable maturity, thin fruit skin, soft flesh, and sugar content of more than 20%.
(2) Wash with 1.5-4.0% sodium hydroxide solution, wash away the waxy and harmful microorganisms attached to the peel, and at the same time can be disinfected, and make the peel appear fine cracks to facilitate water evaporation and promote drying.
(3) There are natural drying and artificial drying. Natural drying: the raw materials for processing and washing, put into the tanning plate for 3-5 days, then flip, continue to dry for 2-3 days, and then put the tanning tray in the ventilation room to be stacked in the shade to dry, about 30 days, the mouth color is bright green, the quality is excellent. Then store back soft for more than 3 weeks, threshing and destemming, packaging. Manual drying must have good heating and heat preservation, ventilation and water dispersion equipment.
2. Processing of grape juice
(1) Select varieties with good flavor and juicy. The fruit should be fresh and fully ripe, and the underripe, overripe and mechanical wounds should be removed.
(2) The fruit is soaked in 0.03% potassium permanganate solution for 3 minutes, and then rinsed in flowing water until the water does not have red color.
(3) Remove the stem. The fruit is crushed with a crusher or crushed by hand. Heat the crushed fruit to 60-70 ° C for 15 minutes to allow the pigment of the grapes to penetrate sufficiently into the juice. Pressed by a press or hand, the broken fruit is juiced, and filtered and removed from the slag with a flannel bag, and the juice is moved into the storage bucket.
(4) Use the sugar liquid with a concentration of 20% to adjust the sugar content of the juice to 16%, and then add metatartaric acid to the juice, generally adding 2% of the metatartartaric acid solution to every 100 kg of fruit juice 3 kg. The preparation method of 2% metataric acid solution is: weigh 1 kg of metatartartaric acid, add 49 kg of water, soak for 2 hours and cook for 5 minutes, stop heating and stir thoroughly, so that it dissolves rapidly and immediately filtered with flannel, add water to 50 kg, and quickly cool and set aside.
(4) Add 4-6 grams of tannins to 100 kg of juice, and add 6-10 grams of gelatin after 8 hours. The clarification temperature should be 8-12 ° C. When the juice flocculents are all sinking to the bottom, after aspirating the clarifier with a siphon, heat the juice to 80-85 ° C with a sandwich pot.
(5) Put the juice into a sterilized glass jar, cover and seal in hot water at 85 ° C for sterilization for 15 minutes. During the processing of grape juice, it is necessary to strictly prevent contact with iron, copper and other metals, and the juice squeezed out is bottled at room temperature and sterilized in 85 ° C water for 15-20 minutes.
3. Processing of wine
(1) Select fresh, fragrant and fully ripe fruits, and remove rotten fruits and green fruits. The fruit is destempered, soaked in 0.33% potassium permanganate solution for 20 minutes, and rinsed with running water until there is no red in the water. It is then crushed with a crusher, but the seeds cannot be pressed, and the fruit should not be in contact with copper and iron containers during the crushing process.
(2) To brew white wine, green varieties should be selected, and the juice and slag of the broken fruit should be placed in a water tank, a jar or a glass bottle for fermentation. It usually takes about 5 days.
(3) The skin residue after full fermentation should be separated in time. The separation method is: using a bamboo sieve coarse filter, pressing with a manual or small screw press, the juice is loaded into a disinfected glazed small mouth jar, the amount is 95% of the jar capacity; then add sulfur dioxide, the dosage of 100 liters of grape juice or 100 kg of grape skin residue added 6% sulfurous acid 100-150 ml, evenly stirred.
(4) The general grape sugar content is about 14-20 grams / 100 ml, so it can only produce about 8-11.7 degrees of wine, and the alcohol concentration of the finished product requires 13-18 degrees, so it is possible to generate 1 degree of alcohol according to the need for 107 grams of granulated sugar, calculate the amount of sugar required, and add to the original wine.
(5) After the fermentation of the original wine is added to the granulated sugar, it is slowly carried out at 15-18 ° C and fermented for 1 month. The wine is sucked into the barrel with a siphon and stored at a temperature of 8-12 ° C to allow it to mature. The storage time takes about 1 year.
(6) Clarification and filtration with aspergillus niger extracted fermentation preparation for clarification (also can use egg white, pectinase, etc.), filtered to remove the fine residue in the wine, to obtain a clear liquor. The wine is placed in sterilized glass bottles, sterilized in water at 70-72 ° C for 20 minutes, and then cooled.