Our aim is to allow as much of the must as possible to start fermenting on its own, with its own natural yeasts. We do not use any anti-botrytis on our vines, which significantly helps to establish a viable yeast life on the skins of the grapes. In cases where there are problems or specific risks, or when the fermenting process does not begin of its own accord, we carry out the yeasting using stocks of yeast species specific to the Alsace winefield.
The temperatures at fermentation are carefully managed so as to avoid extremes. We have a "natural" method of doing so, a method used since time immemorial, consisting of choosing the type of vat, its positioning and its surroundings in the cellars according to the grape variety and the type of wine desired.
Thus a wine which is likely to rise in temperature will be placed in a draughty part of the cellars where the heating will be tempered. The temperature of grape varieties with subtle, floral or fruity aromas (such as the Sylvaner, Pinot Blanc, Pinot, Auxerrois, Riesling or Muscat) is regulated by the circulation of cold water through trailling devices in the vats. The aim is simply to avoid over-high temperatures which can damage a wine by reducing its fruity or floral characteristics. The only additive which oenological science will not allow us to do without is SO2.
The question of eliminating SO2 is a difficult one. We do, however, carefully calculate the amounts used, and make sure they are well under the maximum doses permitted. The fact that our wines are made of grapes which come from relatively deep and partially calcareous soils means that they need time to fully express themselves. The expression of a soil only comes about several years. In order to reach such a stage of development it is necessary to ensure that the wine will keep well.
Today the addition of sulphur dioxide is the only efficient way of conserving wines, and therefore of reaching an expression of their soil.
Our internal laboratory is able to carry out an accurate and advanced running analysis of the vats. This allows us to monitor the chemical balances achieved by the wines over the courses of the different stages of fermentation, and above all allows us to avoid them developing in a direction we do not wish for.
Hundred year-old oak casks are employed as tools for wine processing and creation. The casks, each with their own personality, are chosen according to the grape variety and the intended wine. Using them is never a question of wishing to add a woody flavour to the wines. Casks are merely vessels which are less water-tight and more air-permeable than vats. Casks also have properties of thermal conductivity which can be interesting for certain wine-making processes.
There is a technique of clearing a wine of the cloudiness which can appear under certain conditions, based on the powerful absorbing properties of the clay bentonite. It is not used systematically in every case, but an analysis of each vat is carried out to determine if it is needed.
If there is a need, we carry out the clearing process using limited doses of clay. We have, however, observed that a very large number of wines never need clearing by adsorption, and the stability of the wine is never adversely affected by missing it. Each year we carry out tests to improve our knowledge of this subject. The aim is only to carry out clearing by adsorption on wines which really need it, and even then to do it with a minimal dose of clay, so as not to spoil the developing fragrances.
After resting on the fine sediment for 8 to 11 months the wines are filtered in the springtime, and then are either bottled straight away or are stocked in vats or oak casks ready for their eventual bottling in our storehouses.
The bottled wines are then left to mature in our storehouse, until they reach their optimum potential, and are put on the market.