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I have a half ton of Merlot… that seems to be getting some volatile acidity…

TroubleShooting

Luke Chiurco — Santa Rosa, California asks,
Q

I have a half ton of Merlot in my garage in a barrel that seems to be getting some volatile acidity from taste. I’m getting it tested now. What is the best way to fix my wine if this is the case?

A
Short answer (and it might work if your volatile acidity (VA) level is low enough, say, under 0.55 g/L, depending on your sensory threshold) is to bump up your free SO2 and see if the smell goes away. Sometimes what we perceive as “VA character” can actually come from aldehydes, which get bound up with sulfur dioxide. Often that’s all it takes to make the “VA smell” and taste (which are intimately connected in our sensory world) go away or diminish to a point where the wine is acceptable to you.     However, when you get VA or aldehyde in your wine (which can come from many different sources too numerous to recount in this part of the column you should see it as a very large flag of the red persuasion, if you know what I mean. It generally means that you’ve got someone growing in there that you don’t want and it also possibly means that your wine is not as topped up (completely full in the barrel) as it should be. Bacterial infection, oxidation and VA all
Response by Alison Crowe.