What's the difference between a smoky wine and a smoke-tainted wine?

Hello there! I'm Dr. Vinifera, but you can call me Vinny. Ask me your toughest wine questions, from the fine points of etiquette to the science of winemaking. And don't worry, I'm no wine snob—you can also ask me those "dumb questions" you're too embarrased to ask your wine geek friends! I hope you find my answers educational, empowering and even amusing. And don't forget to check out my most asked questions and my full archives for all my Q&A classics.
Dear Dr. Vinny,
Concerns over smoke-tainted grapes and wine have recently been making news. But some wines are praised for their smoky aromas, so what is the difference between the quality of smokiness and the flaw of smoke taint?
—Jocelyn, Pennsylvania
Dear Jocelyn,
That's a great question! You’re right that some wines have a pronounced smokiness that some people like. A lot of that can be credited to the amount of toasting an oak barrel receives before the wine is aged in it. The sensations that are created by aging a wine in a toasted barrel are quite different from those of a grape that has been hanging in smoky air for an extended period of time (although some people like that, too!).
We’ve written extensively about the science behind smoke taint, so I’m not going to go into that here, but smoke-tainted wines can taste acrid or even ashy. As you might imagine, those aren't particularly prized qualities, and research has shown that consumers are more likely to react negatively to smoke-tainted wine.
Brand loyalty is built on consistency, and if you buy Dr. Vinny’s Reserve year after year, you might not like it when Dr. Vinny’s Reserve suddenly tastes like a campfire. You might look for other wines instead, so many winemakers are wary of risking their reputation on smoke-tainted grapes.
That said, I’m sure there are some wine lovers who would get a kick out of trying a smoky wine, knowing the grapes were affected by nearby fires. A vintner in California's Anderson Valley told me that his customers loved the smoky notes in his 2008 vintage, a year in which Northern California was plagued by wildfires. It's not surprising that someone might feel more emotionally connected with wines from vineyards that have survived wildfires.
While a little smoke taint might be a fun novelty in a $15 bottle of wine, you might feel a little differently if it was a $200 bottle of Napa Valley Cabernet. I think one of the most worrisome things about smoke taint is that it’s so unpredictable. You can test to see if some markers are there, but it might not show itself for years. There are things you can do to mitigate its effects, but there are no guarantees.
—Dr. Vinny