What's a sulfite and what is it doing in my wine?

Sulfites are a compound prevalent in most wines. Together, the sulfur and oxygen in sulfites act as a powerful preservative to keep the wine from oxidizing too quickly, which can change the flavors of the wine for the worse.

"It's really hard to drink a wine without sulfites," Harbertson said.

In fact, yeast actually makes some of these sulfites. Harbertson said that different colonies of yeast in wines will sometimes fight each other by creating sulfites that some strains are more sensitive to. Some people are sensitive to sulfites — which are also found in other foods as a preservative — in which case the best thing to do is avoid them.