The Important Role of Oak in Winemaking

Why does oak matter so much?

Wine barrels in wine cellar
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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. The world's most expensive wines almost always enjoy their fair share of new oak. Whether it's French, Hungarian, American, or others, oak contributions leave a lasting mark on the bottled 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 to Wine?

Oak provides flavor and aromatic support to the wine while adding richer, fuller impressions and complexity. For 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. For 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 from where it’s prototyped. 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. Hungarian and Slavonian 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 can easily run over $1,000 a barrel depending on the forest from where it is sourced. An American oak starts at around $360 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; use that same teabag another time or two, however, 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 the 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 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.

A Word About Oak Chips and Wine

It is not uncommon for winemakers to skirt the barrel altogether and use "oak chips" to "season" a wine in the winemaking process. These chips dramatically cut costs and can be utilized in either the fermentation or aging phase of the winemaking process. The oak chips come in a variety of forms and flavors and will actually speed up the oak flavoring process due to higher oak concentrations and more surface area contact with the wine. Oak chips are placed in a mesh-like sack and then “steeped” (again similar to a tea bag) in a tank. It’s only been since 2006 that oak chips have been legally permitted for use in Old World winemaking practices.

Oak plays a pivotal role in the winemaking process for many favored varieties and wine blends. However, one of the best ways to see the influences of oak is in a side-by-side comparison wine tasting. Chardonnay is one of the easiest varietals to do this component tasting with, as many winemakers utilize a good bit of oak to bring out the toasty, buttery notes that many consumers have come to expect from Chardonnay.

Just grab a bottle of well-oaked Chardonnay and an "unoaked" Chardonnay (typically labeled as "unoaked" or "naked" Chardonnay) and do a side-by-side taste test. With the oaked version, you should be able to see the oak’s dominant influences in the smoky, toasted notes often leading to a full-flavored, buttery finish. With the unoaked version of Chardonnay, you will see pure varietal fruit dominate–likely brimming with peach, apple or pear, and warmer tropical fruit if sourced from a warmer region.