(WP) - Let’s face it: Wine language is confusing.

Many of the world’s finest wines (and many more inferior ones) are aged in oak barrels, but if a wine tastes “oaky,” well, that means it tastes like a tree. And if there’s one thing we should all be able to agree on, repeat after me: Wine should not taste like a tree.

So why age wine in oak barrels? Is the barrel room merely a trophy case for millionaires looking to buy into the winery lifestyle? It is certainly effective bait for tourists. A stack of barrels holds the promise of wines to be enjoyed in the future. We smell the heady mix of wood and wine. If we’re lucky enough to be offered a barrel tasting, we salivate with expectation as the winemaker loosens the plastic bung and uses a glass “thief” to draw a sample and squirt the inky juice into our glasses. There’s a sense of adventure to a barrel tasting, as though we are stealing a bit of the future. Even when we are just visiting, we are witnessing the transition of last year’s vintage into next year’s new release — or so we think.

Something is happening, though. Those barrels are more than expensive decoration. They contribute structure, body and tannin to the wine, while helping to clarify and stabilize it. They also expose the wine to a measure of oxygen (through the wood, but also when the wine is “racked” from one barrel to another to remove the juice from the lees, or sediment), softening the wine and giving it a fleshier mouth feel.

As long as it doesn’t overwhelm the fruit, oak contributes many of the flavors we associate with fine wine. To taste oak’s influence, compare a barrel-fermented chardonnay with one labeled “unoaked.” The latter will taste fruity, while the barrel fermented one will most likely taste spicy, with flavors of clove, nutmeg and vanilla. It may also have the drying sensation of tannins (though this is typically more noticeable in red wines). If you sense toast or smoke, that’s most likely barrel influence as well.