Wine Words: Oxidative vs. Reductive Winemaking

Oxidative and Reductive are both wine words often used to describe a style or philosophy of winemaking. Do you know what the two terms mean and how they differ?

Oxidative and reductive are opposites that depend on the relative presence or absence of oxygen during winemaking. Oxidative winemaking means more aerobic winemaking in the presence of oxygen (usually controlled amounts). In contrast reductive winemaking means winemaking in more of an anaerobic environment without oxygen.

Reductive winemaking is all about protecting the grapes, the must (juice) and wine so that the primary fruit aromas and flavors are preserved. Wines made reductively are typically very fresh, more fruit driven and paler in color. The use of more sulfur dioxide and inert gases as well as fermentation at cooler temperatures is all part of the reductive winemaking toolkit.

Oxidative winemaking is less about exclusively preserving the primary fruit aromas and flavors. By allowing some (controlled) oxygen exposure, the wine can develop some non-primary fruit and textural complexity. To illustrate the point: an unoaked New Zealand Sauvignon Blanc is a good example of a reductively made wine and a barrel fermented California Chardonnay is a classic example of a wine that had controlled exposure to oxygen.

Too much oxidation or too much reduction: Oxidative and reductive are two polar ends of an extreme. Wines are rarely made either totally oxidatively or totally reductively because each extreme carries risks.

For oxidative winemaking the risk is oxidation. It is important to point out that wines made using more of an oxidative handling philosophy are not oxidized. Oxidation is what happens when the wine has had too much (uncontrolled) oxygen exposure. The wine turns brown, becomes flat and tastes like a bad sherry!

Similarly an overly zealous reductive philosophy has its own potential risks. Volatile sulfur compounds can develop. These smell like burnt match, garlic, onion, leek or rotten egg. Not something appealing in a wine.

Wines made using more of an oxidative approach tend to be more stable. Some exposure to oxygen early on during winemaking acts almost like a vaccine, rendering the resultant wine less vulnerable to the negative effects of later oxygen exposure.

Most wines lie somewhere in between, with the double aim of safeguarding the fruit character, while at the same time enabling non-fruit and textural or mouth feel complexity.