White wine vinification is the most widely used in Alsace, differing scarcely from that practised in other regions.
After the grapes are picked, they are passed through a “fouloir”, a machine which serves to burst the grapes that will then be pressed in horizontal or pneumatic presses in order to gently extract the juice. After this pressing, the juice is stored in tanks according to grape variety and vine parcel origin.
Next in the vinification process is “debourbage” or “settling of must,” eliminating suspended must particles from the juice by forcing them to the bottom of the tanks. This is done to avoid any sediment from imparting unwanted flavours to the wine.
This is followed by the fermentation phase, which consists of the transformation of grape sugars to alcohol as a result of natural yeast present in the must or by adding cultured yeast.
This process unfolds either in old wooden barrels, or, as is more and more often the case these days, in stainless steel tanks. This phase can generate critical increases in temperatures (up to 88° F) which may be potentially damaging to the quality of the wines. In order to avoid this, systems for controlling and regulating temperatures are systematically used.
After three or four weeks, at the end of fermentation, the wines are racked in order to eliminate the most important lees (sediment and dead yeasts that have exhausted their resources in sugar) and are transferred to storage tanks where they age on fine lees for three to four months. Because of a desire to maintain natural freshness in the wines, winemakers do not want to achieve malolactic fermentation.
Before bottling, it is important to clarify and stabilize the wines. The process aims to eliminate all of the suspended particles in order to ensure perfect clarity and brilliance in the wine. This is done on kieselgur stone or on slabs. In order to regulate levels of tartaric acid in the bottle, the wines may be maintained at low temperature (21 degrees F) for two or three days. The final stabilization is ensured by passing through sterile slabs or membranes at the time of bottling. This takes place quickly compared with other regions, starting in the months of February and March for the wines selected for immediate consumption.
The premium wines intended for ageing are bottled just before the following harvest. The storing and maturation of Alsace wines generally takes place in bottle.