This paper introduces the specific brewing technology of wine in detail.
1, grape picking
Grape picking wineries usually pick white grape varieties first and then red grape varieties. Especially in the black period, the winery will focus on monitoring and grasping the best picking opportunity.
There are also two kinds of picking methods, manual picking and machine picking.
If you pick the grapes by hand, you will cut them off one by one with special scissors. Although this method is slow and consumes a lot of manpower, you can choose the grapes and do less damage to them.
The principle of machine picking is that the machine shakes the grape trunk and shakes the grapes down. This way, you can't pick grapes. What you want is speed and less manpower.
Because of the hot weather, some wineries will choose to pick the grapes at night, which reduces the oxidation of the grapes. After picking, they will be packed and sent to the brewery.
2. Sorting
After the grape fruit is sent to the brewery, if it is to brew high-quality wine, the grapes will be placed on the sorting table for selection, and the immature or rotten grapes will be selected.
3, stem removal and crushing
Only those fruits that have been picked by hand have fruit stalks, so it is necessary to remove them. The treatment method is to treat them together with the crusher. The crusher breaks the grape skin, and a small amount of juice will flow out at this time, so the crusher should be as gentle as possible to avoid damaging the grape seeds, otherwise bitter oil and tannin will flow out.
4. Cold impregnation
After the grape skin is broken, it will make the skin and juice contact at low temperature for a period of time. This process is called cold impregnation. The temperature is generally 4- 15℃, and the duration varies from hours to days to weeks.
Cold soaking can enhance the fruit flavor and texture of wine, especially white wine varieties. Cold soaking of red wine can enhance the aroma of fruit and deepen the color of wine, but tannin will not be extracted during this process.
5. Squeeze
Squeezing is the process of separating grape juice from pulp and peel, which is carried out before fermentation for white wine and after fermentation for red wine.
The first and last pressed grape juice will be very different in texture and taste. As far as red wine is concerned, as the pressing continues, the color of the wine liquid will be deeper and deeper, and the tannin content will be higher and higher.
After pressing, the white grape juice will stand still for a period of time, allowing the impurities in the liquid to deposit on the bottom, and taking out the clarified grape juice for fermentation.
6. Fermentation
The process of fermentation is to convert the sugar in grape juice into alcohol and carbon dioxide, but the grape juice gradually becomes wine.
The fermentation temperature of white wine is generally between 12-22℃. Bottom fermentation temperature can slow down the fermentation process and make wine produce more subtle flavor. Fermentation is usually completed in a few weeks.
The fermentation temperature of red wine is generally between 20-32℃. Higher temperature is beneficial to the extraction of tannin and color.
After alcohol fermentation, red wine will undergo malic acid-lactic acid fermentation, while white wine will avoid this step.
7. Curing
Generally, cheap wines will not be aged, but for those high-quality wines, this process is very important, which can help wines to present more delicate and complex tannins and flavors. If the brewed wine requires more fruity flavor, the winemaker will store the wine in an inert container for several months, then filter and bottle it. However, for wines with high tannin, high acidity, high alcohol content and development potential, especially red wine, it is likely to be aged for several years, and the aging process is mostly completed in oak barrels.
8. Bottle
When the winemaker thinks that the wine is old enough, he will consider bottling. Before bottling, he should glue and worry about the wine as needed to get a clearer liquor. However, some winemakers think that this will affect the negative effects of wine flavor and texture, so they don't glue and filter, and bottle directly.
As for sealing, except Australian and New Zealand wines are sealed with screw caps, other wines are basically sealed with oak plugs.