Pressing of white grapes

the slightly colored wines

If you have the chance to participate the grape harvest the following information will be useful.

The slightly colored white wines, are produced by pressing directly the grapes before fermentation at low temperature. The direct pressing avoids leaving the molecules of the skins diffuse into the juice.
But if the grapes are white why pressing the grapes before fermentation? Indeed, white grapes does not mean colorless. Thus, the skin give a color green-yellow to the wine for the grapes harvested early (such as for the Sauvignon variety), and in yellow-brown for the grapes harvested to their full maturity (such as for the Chardonnay variety). For now, many customers prefer the slightly colored wines (also called low oxidation), so we use the direct pressing to prevent staining of the skin.

The following points outline the seriousness of the producer

The filling time of the winepress

This filling time is critical. If the winepress is too long to be filled (4-5 hours) the juice will be in prolonged contact with the skins and there will be a beginning of maceration, therefore diffusion of the molecules of the grape skin to the juice and more oxydation. This will force the cellar master to increase the dosage of SO2 to reduce oxidation (and this is not a sign of quality). A slow filling may come from a failure of the harvesting machine or trailer that brings the grape, we can not do anything and sometimes it happens. A slow filling may also come from poor communication between the cellar and the vinegrowers. This last point may recur often during the harvest and affect the quality. This is a simple thing to observe from the outside and very revealing.

Keep whole berries

To reduce the oxidation of the grape it requires whole berries. See if the berries are whole is very easy to observe inside the trailers arriving at the winery. Whole berries are synonymous with good quality for further operations. Note: Trailers are often small but sometimes not: large trailers (3-5 tons) flat-bottomed crush too much grapes below and decreases the quality.

Avoid heat and sunlight to reduce oxidation

If you made an apple juice it will brown quickly, this is the phenomenon of oxidation that is to be avoided during the grape harvest. A simple way to reduce this phenomenon is harvesting at night to avoid heatand sunlight. Growers who agree to harvest at night show a great commitment to quality. It is also the sign of good relations because harvesting at night is quickly tiring and this create some mood swings that must be manage.

Two types of juice

The juice flowing by gravity progressively when the winepress is filled is called the free-run juice. There is normally slightly colored. Then pressing the grapes that remain in the winepress: this juice is called the press juice. This one is often more colorful, almost brown. This press juice will release a more aromatic wine but with a color that does not suit the consumer. These two types of juice will be assembled in the proportion best suited to taste.

Below the grapes after a complete cycle of pressing.

Once the juice is removed, the remaining part is the pomace. It can be used in the food industry as livestock feed.