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Properly Adding Acid to a Barrel


Robert Masiello — Haverstraw, New York asks,

We are making approximately 60 gallons (227 L) of red wine. Currently we are trying to reduce the pH from 3.9 down to at least 3.6. According to some books, doing this in half cycles is better by calculating ppm for SO2 and adding half of the recommended total acidity (TA) to reduce the wine while racking out the lees. This is done all at the same time to reduce the wine’s exposure. Then a couple of days later, reducing pH IN the other half by putting the rest of the recommended TA in and stirring.

Of course we only have an inexpensive pH meter and we cannot measure TA at all. I am not even convinced that we can effectively stir the TA throughout a demijohn or carboy with just a rod in the second phase of lowering the pH. At least not nearly as well as when we pumped wine from one vessel to another allowing the chemicals to swirl throughout.

Please let me know if there are any other techniques that you can offer for reducing pH and effectively mixing.

A I agree with you in that acid adjustments, especially big ones, can best be made in two steps. That way you can see if you like the result as you go along. However, since you do have a pH meter, as well as a pH target, you can do a little bench trial first. Take, say, a 100 mL sample of wine from your fermenter (barrel, I assume) and add 1 g/L to it by measuring out 0.1 g tartaric acid on your gram scale. (As an aside — every home winemaker should own a 500 g x 0.01 g scale so you can measure little amounts of additives for bench trials.) Stir the acid into your 100 mL sample and measure the pH. Give it a taste. Do you like it? Do you want to add more? Since you’re starting at a pH of 3.9 and want to target around 3.6, depending on the buffering capacity of your wine, you’ll most likely end up adding around 2 g/L. I would say you’re even better served just having a
Response by Alison Crowe.