When I first started drinking wine, I couldn’t differentiate between a chardonnay aged in a perfectly charred French oak barrel and one aged in a box. Along the way there have been classes, books, winery tours, and all kinds of hands-on learning experiences. Slowly I have developed a level of appreciation for those fabled barrels.
A quick explanation would be that aging wine in charred oak barrels allows it to develop flavors of toast, nuts, spice, and smoke, while wines that escape the grasps of the barrels have more pure, fresh, fruit-driven flavors. French oak is subtle and imparts a complex finish, which helps soften the tannins in a wine. American oak is more robust and creates a creamy, buttery wine with strong vanilla notes. But let’s delve further…
During a brief recent stay at Halter Ranch Vineyard and Winery in Paso Robles, Calif., I was lucky enough to tour the winery’s caves, where winemaker Kevin Sass has set out on a little experiment: He has put the same 2012 cabernet sauvignon into a variety of different barrels, both French and American. We were able to try four samples of the cabernet out of three French and one American barrel. The American-oaked wine had hints of lead that came across as pencil shavings on the nose with almost overwhelmingly bold blackberry and cocoa notes. This sample was the least favorite of the group. The French-oaked samples were similar to each other, with delicate differences. While the nose remained the same, it was the complex finish that allowed these wines to stand out. It was a unanimous decision: the barrels from Tonnellerie Taransaud in Cognac, with medium toast (the amount of charring of the wood over open fire), offered up the most delicious, full-bodied, complex wines.
While Sass is a fan of Taransaud, he explains that this experiment (which is carried out annually) is used to determine which oak works best with which wine. Sass made it clear that brand popularity is never a factor in choosing a barrel. A particular brand (or variety of oak; see below) might be popular with fellow winemakers during a given season, but Sass won’t necessarily choose that barrel unless it yields the best wine from his experimenting. He acknowledges that making these decisions every year can be laborious and expensive, adding that he often buys hundreds of barrels from France at great cost. After they've been used once, he can only sell them at a loss or just give them away. When Sass has had disappointing results from certain barrels, sales representatives are quick to suggest that he ask for a different toast level when he orders the next time, but Sass claims it’s never the toast, it’s the oak itself.
French oak barrels, like Taransaud’s, are typically made from wood grown in one of the five oak forests in France: Limousin, Nevers, Tronçais, Allier, or Vosges. Each forest produces trees with distinctive aromas and flavors, so much so that some connoisseurs can identify the forest by tasting the wine. Barrel-makers are able to blend different types of white or dark oak, creating subtle differences in character for each vineyard to which they sell. Similarly, some barrels are toasted lightly, some to a medium degree, some heavily — while others aren't charred at all.
American oak is slightly less expensive, since it’s grown in a number of large forests in regions ranging from California and Oregon to Minnesota and even Vermont. For that reason, it tends to be more common in American wineries. In this case, the trees are typically white oak and tend to produce more aggressive flavors than their French counterparts. Winemakers will often reuse American barrels to downplay the original bold vanilla notes that an American barrel offers when it's new.
The oak, the toast, the barrels, and the aging process all contribute to the flavor profile of the wine. But, while many winemakers will argue that barrel-aging is essential to produce complex wine, it certainly isn't essential. For years my mother refused to drink chardonnay, claiming the "oakyness" in the wine made her sneeze. Then I introduced her to unoaked chardonnay, aged in stainless steel vats instead of oak barrels. She stopped sneezing, and started drinking chardonnay.