This is specific to white wine making. Between the press-stage and alcoholic fermentation, the juice of the white wine grapes can be clarified. The goal: reduce the amount of suspended solids, produced from grape skins, seeds, and even stems.
This is an optional winemaking technique, as some winemakers may choose to retain all (or a higher percentage of) solids to increase the wine’s texture, astringency, and even add some flavors/aromas. The higher the level of solids, however, the less of the more fruity aromas will be available in the resulting wine. As such, the technique of lees aging is more commonly used on non-aromatic grape varieties, like Chardonnay. Although, some aromatic grape varieties may see some lees aging, just with a smaller percentage of said lees.
Typically, however, when we think of our more aromatic varieties, like Sauvignon Blanc, or the more subtle-fruited varieties, like Pinot Grigio, it’s a more common winemaking technique to clarify the must. NOTE: Some level of solids are needed, as those skins, seeds, stems provide needed nutrients required by yeast for the fermentation process. (See Nutrients Needed.) Do not over-clarify.
Here are the key ways in which to clarify grape must…