Cheers to Peter Plaehn and Dustin Chabert for your contributions last week on André Tchelistcheff!
This week: Flaws in Burgundy
What wine flaw received widespread attention during the 1990-2000s in Burgundy? Discuss the techniques winemakers have used since to address the flaw.
The wine flaw that has plagued Burgundy for the better part of the past two decades is premature oxidation, wherein the wines (particularly white) are beginning to oxidize very early on in their maturation, causing much panic amongst growers and collectors alike. Many attempts have been made to address the issue, including (but not limited to) cork selection, changing the method of pressing the grapes, decreasing battonage during the elevage, and fully oxidizing the must prior to fermentation.
Ah, good old premox. Batonnage was increased to promote reductive characters and attempt to ward off oxidation, but one of the major style changes involved "macro-oxygenation", where winemakers deliberately let the unfermented must oxidize and brown to eliminate the volatile elements prone to causing problems. Since the flavonoids most prone to oxidation were in the skins and pips, this part of the press juice was often separated from the free run and allowed to brown overnight before being re-integrated to the free run before fermentation. This was a common practice before the advent of the pneumatic press, which protects the juice and skins from air more than the hydraulic presses. Lafon and Roumier use this technique.
Another issue may have been too pristine of a racking into barrel; the absence of no primary lees may have deprived the wine of natural anti-oxidants and caused issues later.
Another school of thought tracks the decrease in sulfur use in Burgundy to a critical point during the 90s and early 2000s, when additions were so low that the SO2 consumed by the bottling process left virtually nothing for the life of the wine.
In short, no one is quite sure why it happened.
I couldn't find the great article that talked about micro ox but here's one by Jasper Morris from World of Fine Wine on the issue.
The great mystery! I do like how the article talks about the effects of premox waning over time. It really demonstrates the concept of wine as being alive.
My understanding is that in general, there are compounds in the must that are prone to oxidation. By exposing your must to oxygen at various points before fermentation you are essentially using those compounds up. Fermentation tidies up any unwanted oxidative qualities, and you are left with wine that is less susceptible to premature oxidation (because there are a finite number of compounds that lead to this, and they have essentially been used up already). The danger is in treating the the wine too cautiously and "protecting" the must and wine from oxygen all the way through the bottling process--it leaves you, counterintuitively, with a wine that is prone to premature oxidation. There is a much more detailed and nuanced description of this in Jamie Goode's The Science of Wine.