How Oak Affects the Flavor of Wine

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It’s been said that right behind grapes, wood is the second most important ingredient in making wine, at least for those wines that are fermented and aged in oak barrels. Unlike the hundreds of grape varieties that are regularly made into wine, when it comes to oak, there are two main choices: American and French. And while both types of barrels are indeed made from oak trees, the two countries grow distinct species that bring different qualities to the wine in contact with them.

France is home to two species, Quercus rubra and Quercus petraea, which have a fine grain, while the Quercus alba, or American white oak, features a wider grain. Hailing from forests throughout the French countryside including Alliers, Limousin, Nevers, and Tronçais, French oak imparts a silkier texture than its American counterpart as well as soft clove, cinnamon, nutmeg, and coffee flavors and light hints of vanilla alongside smooth or polished tannins. American oak, which transmits more profound notes of caramel, toffee, coconut, espresso bean, cocoa powder, a more intense level of vanilla, and bolder tannins, is grown in states including Minnesota, Missouri, Ohio, Pennsylvania, Virginia, and Wisconsin.

French Oak

In Burgundy, members of the Latour family were barrel makers before becoming vintners, and today Maison Louis Latour continues that tradition by crafting its own barrels. The only winery in Burgundy to have its own in-house cooperage, Louis Latour uses about half of the 3,500 French oak barrels it produces annually and sells the balance to producers of Pinot Noir and Chardonnay around the world. “French oak’s fine grain and subtle character make it ideal for the balanced, terroir-driven wines of Maison Louis Latour,” says Eléonore Latour, vice president and 12th generation family member. “For our Chardonnays, French oak complements natural richness and minerality. For our Pinot Noirs, it adds depth and a supple mouthfeel while preserving delicate fruit and spice. Ultimately, it enhances what nature provides, never overpowering it.”

French oak isn’t just used to make wines in France; like many of the grapes from that country that are now grown around the world, its barrels can be found anywhere that wine is made. We recently spot-checked the technical details of more than 100 high-end Napa wines, and of those that specified what type of oak they used, almost every single one used barrels sourced from France. At Quintessa, winemaker Rebekah Wineburg says the personality of American oak is too brash and bold for the type of wine she makes. Referring to the sweeter, more pronounced flavors that can dominate the palate, she tells Robb Report, “Those characteristics can be wonderful in certain styles, but for Quintessa, which is all about elegance and a sense of place, they would feel out of step. Our goal is to let the vineyard speak, and French oak gives us the nuance and restraint to do that.”

Italian winemaker Tommaso Cortonesi also employs French oak for his Cortonesi Poggiarelli Brunello di Montalcino, using 500-liter (132 gallon) barrels rather than the 228-liter (60 gallon) pièce bourguignonne favored by Latour. Cortonesi’s single-vineyard grand cru site imbues his wine with a naturally powerful and refined tannin structure and “French oak tonneaux help to highlight that profile, bringing out Poggiarelli’s finesse and elegance,” he says. He prefers the bigger barrels due to the required two-year aging requirement for Brunello. “The larger volume allows for a gentler exchange between wine and wood, maintaining balance and freshness.”

American Oak

Far from the U.S., American oak barrels are a mainstay at many Australian wineries, especially those that specialize in Shiraz. “The generous fruit weight and texture of Shiraz can readily absorb even 100 percent new American oak, leading to balance rather than dominance,” says Penfolds chief winemaker Peter Gago. While many of the wines made at Penfolds use French oak, its flagship Grange has been matured in new American oak hogsheads—300-liter (79 gallon) barrels—since it was launched in 1951. “American oak contributes a unique aromatic and structural framework that has become part of Grange’s DNA,” Gago says. “It imparts distinctive characters that integrate effortlessly with South Australian Shiraz’s ripe, dark fruit profile.”

Closer to home, one of California’s most renowned wineries, Ridge Vineyards, holds steadfast to the commitment to American oak first championed by original head winemaker Paul Draper. Current head winemaker John Olney explains that in the 1960s when Ridge began, very few producers were aging their wine in standard 225-liter barrels. “Most wine was stored in large upright wooden tanks frequently made from redwood,” he says. Although many of Draper’s contemporaries began sourcing French barrels, fearing that American oak could be too aggressive, “Paul felt strongly that using French oak with the American Cabernet could leave a wine looking like an imitation Bordeaux,” Olney says. “The belief that Montebello could stand on its own aged in American oak solidified Ridge’s position.” A leader in sustainability, Ridge’s use of American oak barrels also limits its transportation-based carbon footprint.

Why Choose?

Due to the different qualities imparted by the two types of oak, many winemakers worldwide mature their wine in a combination of French and American barrels. Esteemed Rioja winery Muga ages its Prado Enea Gran Reserva in 80 percent French oak and 20 percent American sourced from northern New York and Ohio. While historically many modern Rioja producers use only American oak, winemaker and technical director Isaac Muga Palacín points out that the oak he buys from central France and the Loire Valley “provides a finesse and elegance that no other oak in the world offers.” With an on-site cooperage, Muga makes its own French oak barrels and buys its American barrels fully formed. “We believe that a Gran Reserva aged in 100 percent American oak would be more rustic, and we would lose some of the complexity we have today,” Muga explains.