Winemaking begins with the grapes. It is very important that the grapes reach sufficient maturity. The quality of the grapes is in part a reflection of the quality of the wine. After all, you can make good wine from good grapes, but you can’t make good wine from bad grapes.
3. Hand-pick the grapes and dump them in a half-ton cart.
More and more vineyards are now picking grapes by machine. Machine picking is less expensive. In warmer climates, machine picking can be done in the cool of the night to ensure the quality of the grapes. At night, machine picking is easier than manual picking.
In Bordeaux, the machine can shake the branches of the vine to make the grapes fall off automatically and collect them in a container.
Here are the grapes picked by the machine, while the workers are sorting the grapes.
8. The workers are sorting the grapes picked by hand, removing the rotten, dry grapes, leaves and petioles.
9. After sorting, the grapes go into the destemming machine to be destemmed. When stems are present, they may be slightly or completely squeezed.
10. The remaining stems after destemming.
11. After drying, the grapes are transferred by conveyor belt to storage containers and then to fermentation vessels.
12. For red wines, the grapes are fermented together with the skins. However, in the case of white wines, the grapes are pressed and peeled before fermentation.
The following is a type of fermentation vessel from the Douro region of Portugal – a shallow, open-bottomed barrel made of granite, marble, cement or stainless steel. After the grapes are added to the vessel, workers enter and stomp on the grapes to break them up enough to extract the color, tannins and other flavorful substances from the skins.
13. The picture below shows a traditional winery in the Douro region making wine. After stepping on the skins, the grapes ferment naturally. The workers stir the skins and juice several times a day, which not only helps to extract the substances from the skins, but also prevents the growth of bacteria when the skins float to the surface.
14. Artificial dry yeast can be added to the fermentation process, but some wineries use natural yeast.
Here is what happens when wine is fermented in stainless steel tanks. The fermentation process produces so much carbon dioxide that the vessel cannot be covered. Sometimes the fermentation will take place in a closed vessel with a vent attached to allow the carbon dioxide to escape.
16. During the fermentation process, the skins can be pressed under the liquid using an automatic plunger, i.e. a machine press for the grape wine skins. Sometimes, you can also do this manually with a long lever.
Another method of pressing the skins under the liquid is called “wetting”, where the liquid is extracted from the bottom of the fermenter and sprayed on the surface of the liquid.
18. After a certain level of fermentation, the wines can be released from the container. However, after release, they will be added to the fermentation vessel.
During the release process, the wine can have more contact with oxygen, which is beneficial to the growth of yeast and makes fermentation more complete. In other stages of winemaking, we should try to prevent the wine from coming into contact with oxygen, but at this stage, we don’t need to worry too much about oxidation.
After fermentation, most of the red wines are transferred to oak barrels for maturation. Oak barrels come in a variety of shapes and capacities, the most common being 225-250 liters.
20、Below is a relatively large old oak barrel, it is difficult to bring oak flavor to the wine and can be used to make some special types of wines.
21. After the wine is fermented, the remaining skins, seeds and stems will be pressed to extract the essence. Here is a basket compressor.
22. Below is a bag compressor that can be used to make some red wines and almost all white wines. The compressor’s airbag is filled with air and the grape pomace is pressed in evenly and gently using air pressure. The air pressure in the bladder will gradually increase in intensity.
23、The following is the residue after crushing, which can be used for composting.
24. The following is the material left in the fermentation tank after fermentation of white wine, including dead yeast cells.
25.The following is the maturation process of the wine in oak barrels. The maturation time is from 6 months to 3 years. The barrels are stored in cool underground cellars.
26. During the maturation process, the winemaker checks the condition of the wine periodically, and they also need to rehydrate the wine, as some of it will evaporate.
27.Typically, wine is transferred from one barrel to another or from barrels to stainless steel tanks during the maturation process. The diagram below shows that workers use nitrogen to transfer the wine and try to avoid excessive contact with oxygen.
28. The following is also a transfer of wine from one barrel to another. However, this time, the contact between the wine and oxygen was particularly increased to accelerate the maturation of the wine.
Some wines are not matured in oak barrels, but in stainless steel tanks to maximize the freshness of the fruit.
Once the wine has matured, it is ready to be bottled. However, before bottling, it is often necessary to filter the wine to remove impurities so that the wine looks bright and clear and to avoid the risk of microbial infection. In the picture below, the glass of wine on the left has been filtered, while the glass on the right has not been filtered.
