After the harvest, the grapes pass through a crusher to burst the berries which are then pressed in horizontal or bladder presses to carefully extract the juice. After pressing the grapes, the juice (must) is stored in vats depending on the grape varieties and initial parcels.
Immediately after having been picked, the grapes are quickly brought to the estate. Before being pressed, they can be crushed and stripped. Stripping consists of separating the berries from the stems, limiting the must contact with the stems and preventing any saturation by phenolic substances.
Crushing consists of splitting the grape skin allowing the inner flesh to be removed and liberating the juice called free-run wine.
The grapes are pressed in horizontal or bladder presses to carefully extract the juice.
There are two types of pressing:
After the pressing of the grapes, the juice, called must is stored in the vat depending on the varieties and initial parcels.
After a period of 12 to 14 months, the impurities (stems, berry skins, seeds) called bourbe lie at the bottom of the vat. Then there is the settling of the must process which consists of removing these impurities, either in a static or mechanical manner. The must is then pumped towards the fermentation vat.
Thanks to the natural yeasts or from adding specific yeasts, the grape sugars will change into alcohol and transform the must into wine.
This operation, called alcoholic fermentation, can generate impressive temperature rises (up to 30° C) and can damage the aromatic quality of wines. To prevent the latter, temperature control and regulation systems are systematically present in wine cellars.
It is carried out in ancient wood barrels or stainless steel vats.
Three to four weeks after fermentation, the vines are clarified to remove the largest lees (yeast having depleted it resources in sugar). They are pumped towards storage vats, or barrels, and aged on lees for three to four months.
Filtration of wine is a stabilizing and clarifying technique to remove any floating elements, allowing it have its natural brilliance and clarity before being bottled.
Filtration can be done using filters made of diatome-type earth (Kieselguhr-type filters) or cellulose fibres.
Tangential filtration, or micro-filtration, allows to clarify and stabilise wines in a sole operation without affecting the analytic components the wine.
Before being bottled, it’s necessary to undertake a last organoleptic and analytical characteristic check of the wine by tasting and a final test. Depending on the results, it’s possible that a fining agent s added or a final filtering is undertaken. Bottling generally requires a sterilising filtration carried out on plates or membranes.
Bottling requires using perfectly clean equipment and respecting very rigorous hygiene conditions.
Bottling was made obligatory in the Alsace wine production areas by a law dating from 1972. In addition, all still wines have to be bottled in Flutes of Alsace bottles.