C.

In the Champagne region, oak barrels can be used at the producer’s discretion. Neutral oak barrels in particular are sometimes used for some of the still base wines (vins clairs) that make up a blend. Importantly, neutral barrels (which have been used previously several times) do not impart oaky flavors. Rather, by virtue of minute amounts of oxygen, time spent in neutral barrels can open up a wine and enhance the perception of roundness. And that’s the goal of Champagne producers who use barrels.