This is the flipside of my previous entry on the role of the grape skin, in which we learned that leaving the skins in contact with the must will allow them to impart characteristics like flavour (in addition to colour). Part of the reason that I got so motivated to start this topic was that I felt the need to expand the simple refrain I repeatedly hear -- that "red wine is only red because of its skin" -- and delve into what gives white wine its different shades. Last time I mentioned that sparkling wines are mostly produced from free run juice, meaning that skins have very little influence on the finished product. Whites, as well as reds, can be free run too but for the most part skin plays a larger role in white wine than in sparkling wines. But exactly what?
Routinely, white wine production processes do not enlist the skins as much as red wine's would. Why? Skins on all grapes have tannins which is a useful ingredient in some cases and one you opt to leave out in others. Tannins are beneficial components of red wine because they promote ageability while adding structure; they are detrimental to white wine where their astringency can frequently mask gentle aromatic nuances naturally occurring in white grapes. Temper that basic idea with the knowledge that white wines can achieve some extra zing when skins are exposed to the must. This exposure can be quite desirable as long as it happens before fermentation. Should you ferment the skins, you won't get any of the winning benefits that the skin-in red wine enjoys. So the skin isn't particularly the thing when it comes to white wine.
That said, I still am left to wonder. If we can say that red wine is red in colour because skin pigments seep through the must during winemaking, how do we tell whether a white wine exhibits a hue that is due to its grape skin? Maybe there is no way to say for sure. Maybe one has to ask. Does a white wine's light colour result from its skins' light pigment? Or rather does it simply mean the light colour you see is the absence of colour -- that the skin has had less time to mingle with the must and therefore has not offered much in the way of pigment? And what shade-shaping container was the wine stored in prior to bottling? And also, how has age affected the colour? I guess it's hard to make a general statement just by looking at the colour of the finished product. In many cases, it could be a little of everything -- that is, some colour extracted from the skins, some colour leached from oak barrels, and even some colour produced just from the light colour of the grape's flesh. In an extreme example, Pinot Gris (or Tokay) often creates a white wine varietal that possesses a light blush tone due to prolonged exposure to its pinkish skins during vinification. Then to this distinctive shade additional pigment from its greyish-pink flesh and potential colouring from barrel storage as well as the passage of time. In the end it can look nearly like a a rosé, but it is not since no red grapes are added (but I'll have to save rosé wines for an upcoming post).
Backwash
This is a Backwash backwash. I implied a connotation of noble rot that was misleading when I wrote about Sauternes. I may have suggested that the fungus-spawning vine disease called noble rot was noble because of its Bordeaux provenance. While noble rot is indeed essential in Bordeaux's production of Sauternes -- the world's finest sweet wines -- the use of the term "noble" really serves more of a reference to the Botrytis Bunch Rot than Bordeaux in general. Botrytis Bunch Rot is a non-benevolent form of the same disease that sets noble rot into motion. Noble rot was coined more to distinguish it from the bunch rot to lay praise on the Bordelais areas that champion their Sauternes.