The secret for some wines is the oak

Ten years ago, the words "oaky" and "buttery" were rarely if ever uttered in a wine store or restaurant. Today it is not at all uncommon to have consumers inquire about "oaky" (or in more cases, "not so oaky") wines, and there even are popular brands called Butter and Buttercream.

But what are we talking about here? Are these true flavors, textures or something else?

As with all wine-related topics, the answers are simple — except when they're not.

We'll start with the easy part. "Buttery" wines, unless they have been manipulated by a mad scientist, don't taste like butter at all; otherwise they would be all that any of us drink, as would be the case with wines that taste like bacon.

No, this is about mouthfeel, weight and texture, and it's generally the result of one thing only: a process called malolactic fermentation, in which harsher, naturally occurring malic acids are converted to soft lactic acids (think milk). More prevalent with white wines, the resulting juice is often called "creamy" or "butterscotchy," and it evokes, rather than reflects, butter in the wine.

Which is not to be confused with wines that prompt the descriptor "vanilla." These crop up with wines that have been fermented and/or stored in oak barrels. The wood includes a compound called vanillin, which is one of the primary components of actual vanilla, so this is a flavor that has been imparted to the wine.

And that's one of countless tastes that can come directly from the barrel itself — or the "toast" that has been burnished into it. For starters, if a wine tastes smoky to you, it probably has gotten a stronger toast treatment than you prefer. Because all palates are different, some people who smoke a lot of cigarettes or recently have quit smoking love this element, the smokier the better.

Nowadays, scores of toasting options are available from cooperages, said Dave Ready Jr., winemaker at Sonoma County-based Murphy-Goode.

"We call them toasting profiles and have gotten away from just light, medium and heavy," Ready said. "We're buying 50 different toast profiles from World Cooperage, more than a dozen of which might be considered medium toast, based on the temperature and amount of time they were toasted. It's the temperature and the time that let us pull more vanillin out of the wood."

As toasting has gotten more diverse over the years, Ready, who grew up in Edina, has figured out which profiles he likes best for his zinfandel vs. cabernet vs. chardonnay. He's looking for flavor elements such as nutmeg and clove, but most of all he's looking for what all vintners seek: harmony.

"I like 2- or 3-year-old barrels, because you get better integration and perceived sweetness — not sugar sweetness — and you don't have quite the tannins," said Ready.

That's also why he continues to use Minnesota oak. "It's the same species [as other U.S. oak barrels], but I think they tend to have much tighter grain due to the shorter growing season," he said, "so flavors tend to come out of the barrel a lot slower and you get better integration."

More subtle French oak is heavily favored at higher-end wineries, but some of the great wines from Spain's Rioja region have spent years in American oak barrels. Hungarian and German oak have gained some renown in recent years, as have acacia and other woods.

So it's seriously complicated, and choosing the right barrel types is among the most important aspects of a winemaker's job. Lighter-bodied whites (and some reds) see no wood, and in recent years even heavier-bodied chardonnay is getting more frequent "no-oak" or "stainless" treatments. Basically, the fruit needs to be strongly flavored enough to handle and not be overwhelmed by the oak.

At Chankaska Creek in Kasota, Minn., winemaker Mike Drash lays much heavier wood on Marquette grapes grown in super-rich black soil at Amboy Vineyard, but a much more subtle treatment for the rest of his Marquette. He also throws a bit of oak at a white blend called Four Oak that is 90 percent cold-hardy grapes and 10 percent chardonnay.

"Some people said 'You can't put oak on Minnesota whites,' " he said, "But I love the way it turned out."

As oak barrels have gotten more expensive (over $1,000 in some cases), some wineries have resorted to tossing oak staves or chips into tanks with the fermenting juice. The results are decidedly mixed.

Which fits in with one of the great metaphors in the wine world: Oak on wine is like salt on a steak. It can and should enhance what you're making. But if you can taste it, you've used too much.