I. Preparation before making wine;
1. Vessels and tools: large-mouthed bottles; wine bottles; cork or rubber stoppers. Glass bends; rubber tubes; or plastic tubes; gauze, glass rods.
2. Winemaking tools must be ceramic, non-toxic plastic, glassware, etc.; do not use iron and other metal products. Because after the wine and iron contact, the wine will become black and tasteless; lead and zinc toxic will damage human health.
3. Disinfection of containers: all utensils should be washed with boiling water.
4. Selection of raw materials: the grapes used for winemaking must be fully ripe, and green fruit, diseased fruit and rotten fruit should be eliminated.
Two. Fermentation
1. Principle of the juice of glucose and fructose through fermentation, to produce ethanol and carbon dioxide.
2. Procedure: grapes - de-stemmed ----- crushed - pre-fermentation ----- post-fermentation.
3. De-stemming: remove the grape berries from the clusters, because the stems contain more tannins, and if fermented with the stems, it will bring astringent flavor to the wine.
4. Crushing: Place the de-stemmed grapes in a double layer of clean gauze and squeeze them by hand to rupture the skin layer of the grapes and let the juice flow out. When brewing white wine, only take the juice fermentation, peel residue discarded, brewing red wine, the juice can be fermented together with the peel.
5. Fermentation is the key to winemaking, and whether it is good or bad will determine the success or failure of winemaking. Fermentation can be divided into pre-fermentation and post-fermentation. Pre-fermentation, also known as the main fermentation, is to make glucose and fructose into alcohol, from the beginning of fermentation to the liquid surface scum sinking, no longer occurring bubbles, there is a smell of wine that is considered complete. There are two types of pre-fermentation: open and sealed.
The most common type of fermentation for home use is open fermentation. In the fermentation container mouth covered with a layer of gauze, the fermentation of carbon dioxide can be directly from the gauze gap in the overflow, the liquid temperature is regulated by the temperature is not easy to rise very high. But the disadvantage is that alcohol and aromatics volatile.
The other is sealed fermentation: in the container mouth on the upper end of the fermentation plug, so that the fermentation of carbon dioxide through the fermentation plugs scattered. The advantage of sealed fermentation is that the alcohol and aromatics are less volatile.
It is important to note that when the grapes are crushed and placed in the fermentation vessel, 1/3 to 1/4 of the space should be left so that the fermentation liquid does not expand and spill out. In addition, the dominant factor affecting fermentation is the reproductive activity of the yeast.
For home brewing, there are 2 main factors that affect fermentation: sugar content and temperature. First of all, you should choose raw grapes with high sugar content; if the grapes have low sugar content, you can add some sucrose after 2~3 days of fermentation when the sugar has been mostly consumed. To increase the nutrition of yeast, and at the same time can increase the alcohol. The higher the alcohol content, the more unfavorable it is to the occurrence of stray bacteria. The temperature of 25~30 degrees Celsius is the most suitable temperature for yeast activity. After the crushed grapes are placed in the container for 24 hours, foam occurs on the liquid surface and fermentation becomes started,. If fermentation with skin, the skin residue floats on the liquid surface. When the temperature exceeds 30 degrees, the alcohol is easy to volatilize, must be immediately placed in the shade to cool down the fermentation.
The fermentation of the liquid surface produces a thick scum, isolating the discharge of carbon dioxide and oxygen into; not conducive to the dissemination of heat, but also harmful to the propagation of bacteria, affecting the normal fermentation. Therefore, it should be stirred several times a day with a glass rod.
Post-fermentation: After the fermentation is completed, the original wine is filtered through gauze to remove the dregs, and the original liquid is bottled for post-fermentation. The purpose of post-fermentation is to make the raw grape flavor of the original wine disappear. The purpose of post-fermentation is to make the raw grape flavor of the original wine disappear, and the wine has a mellow and rich aroma. And gradually clarify and transparent.
After the post-fermentation wine in the fall, the bottle should be changed in the winter of that year, and the bottle should be changed in the following spring, fall and winter. The method of changing bottles is; firstly, the empty bottle is sterilized by practical alcohol; or put in boiling water and soak for 20 minutes. With a siphon tube to the original bottle of wine inhaled into the empty bottle; to be the original bottom of the bottle when the dregs of the movement of the siphon immediately stop, so as not to bring the dregs into the empty bottle.
Also note; the empty bottle must be filled to the brim with wine, leaving no empty space, so as not to bring in airborne stray bacteria into the bottle. Then cork the bottle with a cork. Seal.
Three. Calculation of sugar and alcohol addition:
1 Sugar addition: home winemaking should try to increase the alcohol content of the original pre-fermented wine to avoid the occurrence of wine disease. Due to the limitations of yeast activity, the alcohol content of home wines generally only reaches 12 to 13 degrees. To achieve this level of alcohol content, the sugar content of the grape must reach 22 degrees. If the sugar content of the grapes is less than 22 degrees, it is necessary to add sucrose fermentation, the basis and calculation of sugar:
Where 17 grams of sugar per kilogram of grape juice, after fermentation can increase the alcohol content by 1 degree. If, the need for grapes in the original juice of alcohol to 13 degrees, it is required per kilogram of grape juice containing sugar 13 X 17 = 221 grams. This value is equivalent to 22 degrees of sugar in the original juice of grapes, in practice, most of the grapes do not reach this level of sugar, so the need to add sugar fermentation.
Home brewing is not possible to use instruments to determine the amount of sugar, only by experience, the general sugar content of about 14 degrees of grapes to eat when feeling the sweetness of the class is still available. To the feeling of the fingers, grape juice sticky hands of grapes; sugar content in about 17 degrees. These cases are required to add sugar.
So a kilogram of grape juice with sugar = 221 - grape juice sugar rate X 1000
Example: If the grape juice contains 14 degrees of sugar (14 grams / 100 milliliters), to be fermented after the alcohol of 13 degrees, should be added to the fermentation of how much sugar? 221-14/100 X 1000 = 81 grams
That is to say: 14 degrees of sugar content of grape juice, add 81 grams of granulated sugar to participate in the fermentation of grape juice. Add 81 grams of sugar to the fermentation to get a raisin wine with 13 degrees of alcohol.
2. Calculation of adding alcohol
Because the raisin wine with 13 degree alcohol is still not easy to keep, so we add food or medicinal alcohol after the pre-fermentation. It is adjusted to 16 degrees. The formula for adding alcohol is as follows:
The amount of alcohol to be added = the amount of original alcohol to be added X the volume of original wine (liters) / the number of alcohol used - the number of alcohol in the finished product
Example: the existing 13-degree grape juice, 10 liters; to make 16-degree wine, how many liters of 96-degree alcohol need to be added?
Alcohol to be added = (16-13) X 10 liters / (96-16) = 0.375 liters
Blending of wine;
After a period of storage; it has been clarified and matured, and is ready to be blended, which can be done according to your own style of preference. Blending can be done by pouring out a small amount of the original juice to dissolve the sucrose, and then introducing this sugar solution into the original container, never using water to dissolve the sugar. Whether you add sugar or alcohol blending, blending must be filtered before bottling and sealing,