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Using Tartaric Acid

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Mike Donabedian — Vancouver, Washington asks,
Q

My wine’s pH is around 4.0 and it is currently undergoing a very strong malolactic fermentation (MLF). I know this will reduce the titratable acidity (TA) to some degree (already at around 6.5 g/L), which could result in a further elevated pH. My question is: Can I safely reduce pH after MLF is complete by adding tartaric acid? Could this help with aging and color stability? Also, do you recommend the use of any sorbate product post-MLF? I have heard that if the MLF is not fully complete, the sorbate can interact and cause odors.

A
I absolutely recommend that you bring your TA up and your pH down after MLF is complete. This is best accomplished by tartaric acid, because wine bacteria will not consume tartaric acid; what you put in your wine will stay in your wine. This will certainly help with aging and color stability because both of these things are compromised by wines that have too high of a pH. I am a big advocate of bench trials before you do a major adjustment to your wine like this. This will help you get the kind of numbers you need (probably at least a 1 g/L addition) without compromising the flavor. Or at least you will reach a “flavor compromise.” My ideal red wine pH post-MLF is around 3.50-3.75 depending on wine style goals and if you add too much acid your wine will taste tart with pronounced tannins. Regarding potassium sorbate as a wine adjunct, I have to tell you I am not really a fan of it and rarely use it in my winemaking products. In fact, I only ever
Response by Alison Crowe.