Smoke residue leads to high concentrations of volatile phenols when grapes are exposed to smoke, particularly between veraison and harvest, which can result in wines with undesirable sensory characteristics. Smoke-tainted wines display aromas such as ash tray, burnt rubber, bacon, disinfectant, or campfire. Lignin, a phenolic compound present in wood, is responsible for the taint. Free volatile phenols (e.g., guaiacol, 4-methylguaiacol, o-cresol, p-cresol, m-cresol) are released into the atmosphere when lignin is burned. Smoke taint has been found in juice and wine made from grapes, as the glycosylated forms of these phenols tend to accumulate in the skin and pulp of the berry. These volatile compounds are released during alcoholic and malolactic fermentation, causing the aforementioned unpleasant sensory characteristics, and they reduce the varietal fruit aroma. While there is currently no cure to smoke taint, the taint can be diminished through careful handling of the fruit. This article will address the primary measures for mitigating smoke taint effects in wine.
According to Tom Collins, Assistant Professor in the Viticulture and Enology Department of Washington State University, it is not known precisely the amount of smoke required for taint to result, or the amount of time the smoke must be in contact with fruit. However, research by the Australian Wine Research Institute (AWRI) has confirmed that grapes are most susceptible to smoke taint post-veraison and leading up to harvest. Mark Kristic, a researcher with AWRI Victoria, has found that the softer the grape skins, and the further through the ripening process the grapes are, the more susceptible they are to smoke taint appearing during fermentation. The main mode of entry for smoke-related volatile phenols is the waxy cuticle
Correct, and it doesn't liberate the sugar-bound phenols that aren't yet volatile. So, if you have those the wine will still get smoky as those compounds hydrolyze. That's what Glen Andrade from Trinchero explained to me.
There is little research on this. I would imagine that unless the building was on fire or the proximity of the barrels to fire was such that the barrels were actually shrouded in smoke I imagine that little smoke contamination would occur to wine in barrel.
Yes, flash-detente can be used to remove volatile aromas however, as you denature the enzymes and aromas in the wine you can also remove the attractive characters. You would have to ask yourself as a producer if the cost of flash-detente can be incurred by the wine style that you might then be left with.
Can flash-detente be used to fractionate- out the associated compounds?
Great article, one question. How does the impact of smoke affect the wine during aging process whilst the wine is in oak barrels? I.e. If there is smoke in the area during ageing. Does smoke have any effect? I am thinking mainly of California where a lot of the fires were in October, once the majority of the picking had occurred.