The long-standing relationship that wine has had with oak is worth investigating, especially since oak barrels have been used in wine fermentation and barrel aging for centuries. Oak is utilized somewhat like a "seasoning" to add flavor and palate appeal to a wine.
Which Wines are Typically Oaked?
Red wine varietals that tend to benefit from a good bit of oak include: Pinot Noir, Cabernet Sauvignon, Merlot, Pinotage, Chianti, Zinfandel, Nebbiolo, Tempranillo and Syrah. White wine varietals that are receptive to oak's influence include: Pinot Grigio, Pinot Blanc, Sauvignon Blanc, Semillon and of course Chardonnay.
Why Oak Wine?
Oak provides flavor and aromatic support to the wine, while adding richer, fuller impressions and complexity. On the nose, oak's primary influences tend to accentuate aromas that center around the spice rack, with clove, cinnamon, nutmeg, vanilla and "allspice" being common aromas derived from a wine's time spent in oak. On the palate, oak's influence turns towards the rich flavors of caramel, coconut, vanilla, cinnamon, clove, smoke, tea, mocha, toffee and butter.
The Oak Barrel and Wine
A typical oak barrel holds either 59 or 60 gallons (depending on where it's prototyped from - Bordeaux barrels or "barriques" hold 225 liters or 59 gallons, where a barrel from Burgundy sits at 60 gallons or 228 liters). Since oak is naturally porous in nature, as the wine passes time in the barrel some evaporation inevitably takes place with about five gallons or so being lost via evaporation. This natural process results in increased concentrations of both the wine's aromatics and flavor profile. The oak used for making wine barrels is influenced by a number of factors. Where is the barrel from? What regional variations have occurred with oak sourced from different forests? How was it dried? How was it toasted? What standard practices are employed by the cooperage that made the barrel?
Types of Oak used in Winemaking
The two most common types of oak barrels used for winemaking are the American Oak barrel and the French Oak barrel. However, Hungarian and Slovenian barrels also have a following with certain winemakers. American oak barrels are cheaper, have a wider grain and lower wood tannins as compared to French oak. They also tend to have a greater influence on the wine's flavor and aromatic components, often imparting vanilla nuances with a little sweeter palate profile than French oak. On the other hand, French oak is the wine industry's "gold standard," offering higher wood tannins and tighter wood grains which tend to have less influence on the wine's aromatics and flavor concentrations than an American oak barrel, but are known to increase the wine's overall palate presence and intrinsic complexity.
French oak runs close to $600 a barrel and American oak comes in at around $300 a pop. With these numbers in mind, it's easy to see what kind of financial investment wineries are making in their barrels and why you pay more for wines that are aged in new oak. Often a winemaker will stagger new barrels into the process to keep costs for the winery and the consumer more reasonable.
What's the Big Deal with "New" Oak?
The newer the barrel, the more concentrated the oak's influence will be on the wine. As vintages wear on, the oak barrels will have less flavor to offer an upcoming wine. For instance, take a tea bag, plucked right out of the box, and you'll get a full-flavor infusion after steeping in hot water, but use that same teabag another time or two and each successive cup of tea will be weaker on the flavor scale. Similarly, after four or five vintages, the barrel may still be used as a "holding" container, but little flavor is expected to be imparted to the wine. You'll see wines that state that a third of the wine was aged in "new" oak, to impart flavor and increase the wine's complexity, but keep in mind that the other two-thirds of the wine was aged in older oak and then blended back together prior to bottling. This effectively saves on the barrel costs, while still adding some oak character to the wine.
Toasting Oak
After the type of oak is chosen a winemaker will decide on what degree of toasting is appropriate for the wine's style. Barrel toasting can be light, medium or heavy, with a lighter toast retaining some of the oak-based character for the wine and heavier toasting or charring giving rise to more oaky and smoky nuances in the wine. By increasing a barrel's toasting, you'll effectively increase the oak's influence on the wine's color, aroma, flavor and overall style.
