Ask Wine Wizard

Do you know why my blackberry wine’s color precipitates out?

TroubleShooting

Dan Derrick — Irmo, S.C. asks,
Q

Dear Wine Wizard,

I have been making wine for 30-plus years and have had reasonable success with most recipes. One exception is blackberry wine. The wine is quite good, but six months to a year after bottling, the color precipitates out. The flavor is still okay, but the sediment is easily stirred up. I have always thought it was probably something to do with pH. However, I religiously use an acid test kit. I have even changed acid test kits, but the problem still exists. I have tried using bottle caps instead of corks, trying to rule out oxidation. Recently, I have begun to purge the carboy into which I am racking the wine with carbon dioxide gas to eliminate oxidation. Any suggestions?

A
Wine Wizard replies: Even though I’d have to see the recipe and an outline of what you do every step of the way to truly diagnose the cause, I can, however, tell you the problem. What we’re looking at here is a classic example of what happens to all wine eventually, precipitation of solids. Even the best Grand Crus Bordeaux suffer a loss of color, tannin, and other goodies over time as the chemical equilibrium of the wine forces these compounds and others out of solution (and turns them into an unsightly glop that collects at the bottom of the bottle). Your situation seems a little bit different, however, because you’re losing a lot of precipitate in what seems a fairly short time. The problem is most likely not one of acidity or oxidation, though both of these things are certainly important parameters in winemaking. Mentally search through your winemaking procedure for a possible culprit, one that might affect or completely upset the chemical equilibrium in the bottle and cause these colored compounds to drop to the bottom like so
Response by Alison Crowe.