Wine Barrel Crash-Course: 10 Types of Oak Winemakers Love
Those sweet “oaky” notes radiating out of your glass of rich red wine? Those “toasty” or “vanilla-scented” notes lifting gracefully from a shimmering Chardonnay? Those aromas translate to flavors on the palate, and are the result of a winemaker’s careful decision to use oak in the winemaking process—either by fermenting or aging wine in oak barrels, or both.
I often hear winemakers referring to the many varying types of oak as their “spice rack.”
Different oaks will lend certain savory or sweet spices, toasty or smoky qualities, as well as vanilla, chocolate, caramel, coconut, toffee or coffee accents. Brand new barrels impart the most oak flavors, while used barrels primarily lend texture, softening and rounding out a wine.
The texture of a wine is one of the most tell-tale aspects of oak-aging. A wine’s voluminous, soft, silky, or plush mouthfeel could depend on the type of oak it was fermented or aged in. Similarly, oak can impart a course, grippy, gritty, or mouth-drying sensation that calls to mind the aftertaste of tea, or the textural sensation from biting into the skin of fresh fruit. A wine may also feel heavy, fat, or light and compact depending upon how well the oak character is integrated in a finished wine.
To help me break down how various types of oak impart different qualities to wine, I spoke with Authentique winemaker Nicholas Keeler, who is also a barrel expert working for Tonnellerie Allary, a renowned French oak cooper.
He says that the trick to understanding the differences lies in knowing the qualities of the varying oak forests and regions from where the wood originates, how long the oak has been seasoned outdoors, as well as how loose or tight the grain of the wood is, and whether the wood has been lightly or heavily toasted.
So, are you ready to become a barrel expert? Here are10 of the most commonly used types of oak in winemaking and descriptions of the characteristics they typically bring to finished wine.
This is one of six main French oak forests that provide oak for making barrels. Because these forests are relatively small, French laws regulate the growing and cutting cycle of a tree’s life. The Allier forest is located in the center of France, about two hours west of the famous Burgundy town of Beaune in the Cote d’Or. Allier yields very tight-grained wood of the Quercus petraea (or sessiliflora) species. “The trees grow tall and straight with tight spacing,” says Keeler. “They produce barrels with soft, balanced tannin.”
Allier oak frames and works with the wine in harmony. Allier with lighter toasts respects vineyard nuance, and with heavier toasts you move into backing spice, toffee and toasted components.
Within the northern reaches of the forests of Allier is a special grouping of French oak trees called Tronçais. “They’re known for producing luxury barrels,” says Keeler. “The tannin of the oak is noble and rich. The trees have been cultivated since the late 17th century to ensure a continual supply for the French Royal Navy.” Because Tronçais oak is extremely tight and fine-grained, wine aging in it is unable to penetrate the wood as it might in looser-grained barrels.
In wine: “Our Troncais oak has completely seamless tannin integration offering richness and volume amplifying the power of the wine, driving the fruit and nuance throughout the finish,” says Keeler. “In comparison to Allier, the oak has slightly sweeter character and lends a luxurious mouth-filling richness.”
Just northeast of Allier and Troncais is this French oak forest where gently rolling hills support tall and straight trees from the Quercus petraea (or sessiliflora) species. “Because of differences in soils here, where silica and clay dominate, the wood produced tends to be very tight-grained, delivering subtle nuance, and tight compact structure,” says Keeler.
In wine: “This is a favorite of mine when it has just a medium or medium-long toast (kind of a middle-of-the-road toast to it) and winemakers use it to age Sauvignon Blanc and Chardonnay,” says Keeler. This oak tends to help preserve the fresh aspect of a wine, lending lifted aromatics and subtle spice and giving a very finely-grained mouthfeel and nuance.
No, this is not where the famous French chocolate comes from, but yes, I’m now thinking about chocolate. Fo-cus. In the northeast of France, west of Alsace, the Vosges French oak forest has been a popular source of oak for winemakers since the 1980s. Keeler says that the grain character of Vosges varies between tight- and medium-grain.
In wine: It tends to impart more robust tannins and deeper, darker, more opulent notes to wine, especially in reds, which take on a particularly “masculine” sensibility. “I enjoy Vosges oak for Chardonnay, Pinot Noir, and with Cabernet Sauvignon, we have achieved exquisite and flashy results with our medium-plus toasted Vosges barrels,” explained Keeler.
In western France, about three hours northeast of Bordeaux, and just east of Cognac near the city of Limoges is the Limousin forests. “This hilly region tends to produce oak that has a wider, looser grain,” says Keeler. “The barrels are slightly more tannic and most popular for aging Cognac, and some winemakers favor them for Chardonnay.”
In wine: You’ll notice broader structure and a presence of the oak, with distinct aromatics reminiscent of the toasted notes you find in the finest Cognacs produced near this famous forest.
Eastern European Oak
In the 19th-century, the very tight-grained Slavonian oak was among the most sought-after wood for large oak barrels and oval vats, especially by producers in northern Italy. But Slavonian oak has taken a backseat in recent years to French oak, which is the standard-bearer for fine wines, and most wines around the world.
In wine: Italian producers have always favored Slavonian oak for their Sangiovese and extremely tannic Nebbiolo-based wines because in larger Slavonian oak casks there is less contact between the majority of the aging wine and the oak—and hence, less tannin-exchange, with almost no tannin exchange in large vats that have been reused year after year. Wines aged in these types of barrels tend to show more fruit-forward notes with very subtle, and well-integrated woody notes.
Primarily culled from the Caucasus region of Russia, on the European border between the Black Sea and the Caspian Sea, this oak is of the Quercus petraea family, and is tight-grained.
In wine: Similar to Hungarian oak, it imparts good tannin structure and subtle oak flavors, allowing the fruit profiles of wine to shine.
Made from hillside forests in Slovakia, Romania and Hungary, these barrels offer a great deal of structure and contribute tannin more quickly than French oak. Winemaker David Ramey, producer of world-class Sonoma Chardonnays and Pinot Noirs, told Lettie Teague back in 2007 that he had been experimenting with Hungarian oak, “because it's a lot like French oak in character but costs half as much,” to which he added, "French and Hungarian oak are the same species.”
In wine: Terrific spice and personality result from wines aged in Hungarian oak, especially, Italian reds, American Merlots and Cabernet Francs, and aromatic reds like the various Rhône varieties.
Missouri / Minnesota / Wisconsin
Although oak from several states does make its way into barrels (not all used for aging wine), most of the American white oak used for making wine barrels hails from Minnesota and Wisconsin, with Missouri close behind.
American oak has proven to be extremely popular with winemakers in Spain’s Rioja region and with Australian producers of Shiraz for the full, rich flavors it imparts—namely coconut—but also because it's about half as expensive as French oak, costing around $500-$600 per barrel.
“American oak is less porous and richer in tyloses, which seals the xylem vessels—meaning it can be cut in more ways than French oak,” Keeler explains. “Oak has to be cut along sap channels so that it doesn’t leak. The way those channels form in French oak is different than in American—French oak must be split hydraulically, along the spa channels so that it doesn’t leak. American oak may be quarter-sawn.”
The takeaway here is that only about 25 percent of a French oak tree can be used for a barrel, while in American oak at least 50 percent of the tree is used.
In wine: The most tell-tale sign of American oak is the aroma or flavors of banana, coconut or pronounced vanillin. Additionally, you might pick up brown sugar and cream soda notes. “If American oak is seasoned properly, the impact is much more subtle and elegant,” says Keeler.
Oregon White Oak
“Quite different from American Oak of the Midwest and East Coast, it has higher tannin levels and requires longer seasoning,” says Keeler. Beyond the different species and forests, each step of the cooperage process impacts the final result and personality of each barrel. “Sun, rain, irrigation and fungi all wash away harsh oak tannins,” explains Keeler. “The longer the oak is seasoned, the drier the oak is considered. Each cooper’s seasoning yard has its own microclimate and ecosystem, lending personality to the final product.”
In wine: If properly seasoned, Oregon Oak tends to impart Christmas spice nuances to wines.