by Marco Montez
I'm often asked about what goes on at the winery during Winter. Most think of winemaking as harvesting, crushing and fermenting which all take place in the Fall, but there is in fact much work performed in a winery throughout Winter.
At Travessia, it is for the most part during Winter that white wines (and rosés if necessary) are clarified. Clarifying white wines is a fairly simple process, but one that is necessary before the wine is bottled. The following is my attempt at explaining one of the types of wine clarification, hopefully without getting too nerdy.
Grape berries contain proteins whose solubility decreases with the wine's alcohol content. These proteins often precipitate in the form of a visible haze in the wine especially when the wine is exposed to elevated temperatures (for example when someone buys a bottle of wine in a tasting room and leaves it in the trunk of a car during a hot Summer day - believe me, it happens…) Although this haze is purely an aesthetic problem since it has no taste, most people prefer their wine to look just like it did when they purchased the bottle.
Most white wines at Travessia are fined with Bentonite which is widely used by winemakers all over the world. Bentonite is essentially an impure clay formed by weathering of volcanic ash. When this Bentonite clay is hydrated in water, the minerals in it become positively charged. Mixed with wine, these positive ions in the clay bond with negatively charged particles (such as proteins) which are floating around in the wine and both sink to the bottom of the tank. Once on the bottom of the tank, the winemaker can then transfer the now clear wine off of the sediment. No Bentonite actually makes it to the final bottle of wine.
There are some drawbacks to fining, the most problematic being the stripping of aromas, flavors and color especially when too much Bentonite is used. So the goal of every winemaker is really to use the least amount of Bentonite necessary to accomplish the goal of clarifying the wine just enough. As a winemaker friend of mine puts it… if someone leaves their fresh milk in a hot car, it's their fault that the milk goes bad, not the cow's. At Travessia I've never used more than 0.4 grams of Bentonite for a volume that would be equivalent to the usual bottle of wine.
And that's Bentonite fining. If you have any questions about this, don't hesitate to ask which you can do by leaving a comment below.