Why would a vintner stir a wine while it's fermenting?
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Dear Dr. Vinny,
I heard in Chablis that when the wine is fermenting, some winemakers will stir the barrels in order to get it fermented more quickly. I want to know the difference between the wine that is stirred when in fermentation, and the one that isn’t.
—David W., Shanghai, China
Some winemakers like to stir a wine while it’s fermenting for extra contact with the “lees,” or sediment, which is mostly made up of dead yeast and bits of grapes. This extra contact with the lees is called sur lie in French. To maximize the exposure, a winemaker might also stir the lees, a process the French call battonage. You’ll most likely come across these terms in reference to white wines, to note their unusual nature—red wines are typically fermented with their grape solids, but white wines typically aren’t.
While I don’t doubt that in the right circumstances it might end up with a faster fermentation, battonage is hardly the practice of a winemaker in a hurry. Quite the opposite, in fact, as it’s a time-consuming practice. Most winemakers I’ve spoken with say that it adds a richer, fuller body and more depth of flavors.
That said, it’s not as simple as saying, “This wine has a rich body, so it must have been made with battonage,” as that’s not always the case. Extended lees contact is just one of the many techniques winemakers have in their arsenal to make the wines they want.