Finessing wine in oak

Whether aging or fermenting, it's all about the barrel

October 19, 2011|By Bill St. John, Special to Tribune Newspapers

The container for wine with which we are most familiar is, of course, the glass bottle. But before it gets there, a lot of our wine spends time in other containers. The most significant of those are made of wood.

Wine in wood — most often oak — makes wine very different from wine in most anything else. Here are some basic terms used when referring to wood and wine and what they mean.

Aged in barrel (aged in wood)

For more than 2,000 years, wine has been stored in wood barrels, mostly as a convenience for either keeping it in place or moving it around. Barrels made more sense than clay or earthen amphorae because they wouldn't shatter as easily, could be sealed more tightly and were round and, hence, able to roll.

But it has only been in the past few hundred years that winemakers and consumers realized that aging wine in a barrel, for short or long periods, improved those wines.

Exposure to the inside of the barrel and through it, to the air outside, affects wine in ways that no other container can duplicate. Because wood is minutely porous, it slowly oxygenates and thereby softens or "rounds out" wines (and, due to evaporation, concentrates character).

Depending on the type or origin or the cooper's treatment of the wood, a barrel further complects a wine with its unique traits, weaving in flavors and aromas (a common one is a vanilla tone) unique to wood.

For instance, sometimes the staves that make up a barrel are toasted by fire on their insides and, given the level of toasting, donate to their wine more or less caramel-like or smoky scents and tastes. "I treat a barrel as a chef does a condiment," says winemaker Robert Pepi. "Wood can marry flavors, add complexity and sometimes improve a wine's 'mouth feel' or texture."

Keep in mind, though, that any of this is extraordinarily rare. "Barely 2 percent of all wine made ever sees wood," says Francois Peltereau-Villeneuve, president of Seguin Moreau Napa Cooperage. "Barrels are only for the very, very best wine in the world."

Fermented in barrel

Some of these very, very special wines come from grapes that are fermented in barrel, which means the wine begins life in wood rather than in any other, more static, container. Fermentation in stainless steel, for example, generally retains the fruit character of the grapes, while wood barrel fermentation may add creaminess to chardonnay or soften the tannins of cabernet sauvignon.

American oak/French oak

Winemakers typically prefer the wood of oak trees and, depending on the style of wine that they make, on oak from a particular place. "I use American oak for my syrahs," says Pepi, "because both the wine and wood have a synergistic affinity for each other." Or, as Peltereau-Villeneuve puts it: "Depends on the grape, depends on the oak."

Oak is a unique wood, and its characteristics are particularly suited for wine (and other liquids, such as bourbon or Cognac). "Oak doesn't have the resins or sap like pine," says Pepi. "You wouldn't want those in a wine."

Given its makeup, oak is a particularly strong hardwood, but nonetheless physically easy to form into a barrel. Think of an oak tree as a small Willis Tower, bundles of tubes running parallel to the trunk fortified by rays running radially from outside in. The tubes are plugged by tyloses, making the grain tight against liquid (and good for storing wine).

Oak grows twice a year, once in spring, again in summer. If a tree has lots of light and grows in warmish climates (in Missouri, say, or in France, near Limoges), its grain is "wide" because both its spring and summer growths are generous. In contrast, cool climates and dense, dark forests (like those of Troncais or Vosges in France) make for denser, "tighter" grained wood.

American oak, as a result, generally donates more wood flavors to wine aged in it, while most French wood gives less. On the other hand, because French oak grain is tighter, it also contains more extractable phenols such as tannins — though those tannins are silkier than the more aggressive, American ones.

New wood/time in barrel

The newer (or less used) the wood, the more it possesses to give to the wine inside it. And the longer wine spends in wood, the more it will take from it. For instance, 50 percent of what a barrel will give to its wine, it gives during the first year. (Thereafter, 25 percent of what's left, and so on.)

That's why you hear so much about winemakers combining American and French oak "treatments" for particular wines; using "both new and 2-year wood," say, for portions of their aging regimen; or the infamous "200 percent" winemakers who ferment in barrel, then age in new barrels or transfer already aged wine into new barrels year to year.

They likes their woods.

Aged in barrel

Oak grows twice a year, once in spring, again in summer with warmer climates producing wide grains and cool climates making tighter grains.
