The grape juice is led into the Qvevri for fermentation. After pressing, the drained mash rests for a night in the Sacnakheli. Only the next morning, a third, a quarter or half of the mash – depending on the sort of grapes, their acid and sugar content – is added to the must. Quite often it happens that the mash of aromatic grapes is being mixed with that of less aromatic grapes. At a maximum of 5 % peels of the grapes are added to extremely acescent grape juice. Less acescent, early harvested grapes, like the ones in East Georgia, which are harvested in mid-summer, are added with red and white mash as well as the crest.
Qvevris are filled up to ¾ with mash and must. Usually the fermentation starts immediately. The skin is stirred three or four times a day. After the active fermentation, the Qvevris are covered with a piece of wood or shale. Leaves are put between the lid and the edge of the Qvevri and sealed with wet clay and in it is the tube so the CO2 can escape.
Once the alcoholic fermentation and optionally also the biological degradation of acids are completed, the Qvevris are being refilled. New wine from one Qvevri is normally enough to refill two other Qvevris. However, the mash from the red wine is being pressed out immediately after fermentation. Qvevris are being sealed and let alone for purification until the end of February or mid March. The then purified wine is being tapped off and pressed through the mash which settles on the ground of the Qvevri. The yeast wine is blended in at a 50:50 ratio after purification. Then one leaves the wine for a few months for further purification. Before the next grape harvest, the wine is divided up in various little Qvevris and sealed – sometimes for many years. Occasionally a Qvevri is filled at the birth of a son and not opened and drunk before his wedding day.
Empty Qvevris are immediately rinsed and cleaned out with warm water and afterwards rinsed out again with water. Antiseptic herbs are being used as a brush to clean the insides. Qvevris are rinsed out until the water is colorless and odorless. Ashes are being spread over the insides and later Qvevris are being used to burn sulphur. Aging is a quality characteristic for dry wines. Whereas sweet red wine or sparkling wine from West Georgia are not stored for long in Qvevris. Sweet red wines are only produced in certain layers; instead of decomposition raisining defines the aroma of the wine.
From time to time, harvest was in December. After the active fermentation the mash is being pressed and the young wine set aside in the cold. These wines are to be kept cool in summer as well. In some special wine cellars it is possible to produce sparkling wine with residual sugar, due to endothermic reaction between water and certain salts, which composes a natural cooling effect.
It needs getting used to traditional Qvevri wines as well as Sherry or Retsina. Nowadays producing wine in Qvevris is more common in Georgia. However, not all producers stick to the tradition a 100%. There are also linked productions, where Qvevris are used alongside modern devices. Practice shows us, that traditionally pressed and produced wines develop a more harmonic structure and a better aroma then machine-made ones. However, the chances are higher, that a dangerous acescence and fleshly aroma occurs. Stripped Qvevri grapes are lacking a specific nuance which is given to them by the wooden crest of more ripe grapes. However, grapes which are pressed through a roll get an unwelcome vegetable aroma.
In Germany, Charlemagne banned pressing grapes with feet. If, however you can obey that rule depends on the ripeness and the health of the grapes. The period for the mash standing can only be defined in relation to the health of the grapes. If the mash is infected with putrefaction, acetic acid bacteria are being reproduced and act as oxidants for botrytis. In healthy vintage, besides saccharomyces cerevisiae, natural yeast is also being reproduced resulting in interesting aroma shades. Due to the increasing amount of alcohol units during fermentation, the ratio between the different yeast will always be affected in advantage of the saccharomyces cerevisiae. The oxidation before the alcoholic fermentation creates the aroma of dried fruits without any negative traces of acetaldehyde.
The color of red wine fades slightly after fermentation and also the young wine shows a slightly brown shade rather than a purple shade, but this also changes after a while. Employing selected yeast is not sensible with Qvevri wine. Through regulating the time of ripening clear wines can be produced and there are no difficulties in fermentation, even with high quality vintage of 105-110 OE°.
Big Qvevri regulate the temperature for fermentation. For an ideal fermentation at a temperature between 20-28 °C, Qvevris with a holding capacity of 1.000-1.500 liters are best suited. This is also the most common size. Using Qvevri with a holding capacity of 4.000 liters is more the exception. There are even archaeological finds of Qvevris with a double wall, a system to cool the water and a holding capacity with up to 10.000 liters. This however, was probably the leftovers of failed experiments.
The walls of Qvevris are diaphanous for water and air. To close the bigger pores, the insides are palmed off with hydrophobic bees wax. This makes it easier to clean the inside and bacteria are not likely to be able to survive on that surface. Moreover, it is not possible for any liquids to diffuse from the outside. However, the smallest pores are free and therefore enable the wine to breathe. Researching the micro – oxygenation in Qvevris is not very much advanced yet, put plays in theory an important role.
The maceration after the fermentation is important for obtaining harmonic wines. During this time, the wine remains on the lees at a temperature of 12-14 °C. Although the whole wine is in contact with the yeast, they taste better than the once already harvested in December. The yeast cells absorb the bitter tasting phenols of the wine. Autolysis of yeast plays a positive role in this process. Despite of the reductive production of wine, there is no Qvevri wine with sulfated aroma, because the wine is not sulphured and features no deficit in nutrients. The first cutting is done before the first warmth of spring, during summer the wine is being cut again and stored till consumption in smaller Qvevris with a holding capacity of 50 - 300 liters. Afterwards the wine ages aerobic, this process is similar to the long aging of champagne in a bottle.