Ask Wine Wizard

Should I try using carbon dioxide whenever I rack to expel oxygen. Or should I bottle sooner?

TroubleShooting

Sam Chiodo — via email asks,
Q

I need help to prevent oxidation. I make about 40 gallons (151 L) from California grapes each year, usually finishing quite nice, but last year’s Sangiovese suffers from oxidation. After fermentation and pressing, the wine spends the next ten to eleven months in carboys fitted with airlocks. I rack at least three times throughout the year by the siphon method. Should I try using carbon dioxide whenever I rack to expel oxygen. Or should I bottle sooner?

A
I have to commiserate with you on the Sangiovese and oxidation dance. For some reason, this grape varietal seems to be especially prone to color (and related oxidation) issues. Much like Pinot Noir, Sangiovese lacks some of the colored precursors that help a wine age gracefully. Some of the compounds that form high color are, in themselves, antioxidants, which is part of the reason a Cabernet or Petite Sirah (both pretty dark-colored wines) tend to resist the oxidative ravages of time. Therefore, even though Sangiovese grapes normally come in with nice acidity levels (which helps to set and stabilize color too), many Sangioveses will turn what I call “bricky” (brick-red with tinges of orange) before you would expect some other wines to change color. Let’s address the low-color nature of Sangiovese first. What you can do to help boost the wine’s color is to use a maceration enzyme, which is typically diluted as a 10% solution in water, then added directly to the red grapes before fermentation. Recommended doses differ from product to product, but one I’ve used before has
Response by Alison Crowe.