Do you love oak?

Many wines you enjoy are influenced by oak. Italy’s splendid Barolo spends years in oak, and the renowned Chablis and Bordeaux wines are oak-influenced. Grand Reserve Riojas spend two years aging in American oak barrels. California Cabernet Sauvignon will certainly be oak-aged, and the list continues.

So, let’s not equate oaked wine with not good.

White wine is not frequently aged in oak due to its delicate aroma and flavors, but some Sauvignon Blanc, Chardonnay, and Chenin Blanc styles are oaked, creating rich, full-bodied wines. For the record, buttery flavors do not come from oak! They are introduced due to malo-lactic fermentation (MLF), which creates diacetyl, a chemical that tastes like butter or butterscotch. So lumping buttery and oaky together in a derogatory “buttery-oaky” descriptor as if they have a common source is inaccurate.     

Truth be told.

Romans’ initial use of wooden barrels throughout their empire was more about efficiency than improving wine. They observed the Gauls (modern France) using wooden barrels for beer storage and, as time passed, abandoned the terracotta containers called amphorae for more durable and transportable barrels. The wood of choice in Gaul of that day was oak because it was abundant in continental Europe’s forests, and the fine-grained oak made for sturdy, watertight barrels. As it turns out, a side benefit was oak added complexity and flavors to the wine. It was later discovered that the porous constitution of oak allows small amounts of oxygen to seep into the barrel, thus stabilizing the color and softening the tannins, improving the wine’s mouthfeel.  

Wine would be dull without oak!

There are two applications for oak barrels; aging wine and fermenting wine; the most common is aging. After fermentation in large vessels, wine is transferred to barrels where beautiful flavors of vanilla, sweet toasty aromas, tea, and tobacco are transferred to the wine. Also, flavors of smoke, spice, clove, caramel, cocoa, coffee, sweet peppers, dill, coconut, dried fruit, nuts, and burnt sugar come through as the wine and wood mingle.

Fermenting wine in oak barrels is even more effective than aging wine in oak barrels. The fresh juice from crushed and pressed grapes is transferred to barrels, where fermentation occurs in this process. This results in a beautiful integration of the oak and wine flavors. The price of barrel-fermented wine is higher due to extra cellar work, and fermentation yeast can affect the barrels requiring time-consuming cleaning. Barrel fermentation is not used for all wine styles and can remove freshness and fruitiness; it’s reserved for making wine with body and structure. For examples of barrel-fermented wines, see barrel-fermented wines from Wine Enthusiast’s site.

Cooperage is an ancient art.

Before a cooper makes a barrel, cut raw oak is stacked on pallets to season for two to three years removing woody flavors and moisture. Once constructed, the cooper chars the barrel over an oak fire to varying degrees of light, medium, or dark toast levels. The barrels are made to order and toasted based on the winemaker’s needs. The most used barrel has a 225 Liter (60 US gallons) capacity and first appeared in Bordeaux. The impact of oak barrels diminishes over time, and their lifespan is typically three to five years; after that, many are destined for tables, planters, or wine storage. Winemakers get 50% of a barrel’s extract in year one, 25% in year two, and less after that. The first year imparts intense toasty flavors; the second year is the best for extracting vanilla with well-balanced flavors. By the third year, flavors probably have diminished to calling the barrel “neutral oak.” Neutral oak is widely used and adds elegance to barrel aging without imparting strong flavors.

Origins of oak and flavor.

The primary sources of oak trees for winemaking use are forests in the US, France, and Hungary. Each tree type has a unique flavor profile. American oak (Quercus alba) is bolder, more aromatic, has robust flavors, more intense vanilla, wood sugars, and toastiness, and allows more oxygen transfer to the wine that softens tannins. The American oak profile is not always desired, and French oak (Quercus sessilis) offers a more subtle touch of oak flavors, less softening but adds good structure to the wine. Hungarian and French oak is the same type of tree, but Hungarian oak has more subtle flavors and delivers unique leather and black pepper notes.

In conjunction with the type of oak is the level of barrel toasting; medium-plus toasting is the most common because it delivers a complex pronounced range of flavors. It’s common to see the origin of oak in wine descriptions and wine labels since it plays an essential role in improving wine’s taste and physical properties. All in all, oak gives winemakers a choice to enhance wine by applying oak as a chef does with the flavors from their spice rack!