A Quick Guide to Oak Barrels

(and how they affect wine)

For almost as long as there’s been wine, it has been stored in oak barrels. Barrels were used initially because they were easy to transport, yet sturdy and durable. It wasn’t until they were well integrated with winemaking that we realized we couldn’t live without them.

There’s no doubt that most of the wines you love have been influenced by oak barrels. But why not Cherrywood? Why does everyone have an obsession with French oak?

In this post, I’ll break down why oak and wine marry so well together and how different styles of oak and oak aging affect the wines we know and love.

Why do we use oak barrels to make wine?

Closed oak barrels have been used since the Roman Empire for their sturdiness, malleability, and leakproof qualities. Once winemakers began to realize using oak positively affected the flavor of wine, the two were forever bound.

Today, we use oak barrels to ferment and age wine because they add depth, length, volume, and complexity. Oak is also porous, which allows water and alcohol to evaporate slowly over time. This concentrates the flavor of the wine. In addition, minuscule amounts of oxygen seep out from the wood, which helps to soften and age the wine.

Lastly, both oak and wine grapes contain a beautiful organic chemical compound called phenols. In wine, the most common phenol is tannin, which imparts bitterness, astringency, and color to red wines. In oak, these phenols impart delightful flavors of vanilla, tobacco, coconut, and occasionally a subtle sweetness.

The many different variations of oak usage:

There are over 300 oak species, yet only three species are commonly used in winemaking. In addition, there are also a variety of sizes, styles, and coopering (barrel-making) methods that winemakers can agonize over as they decide what kind of wine they want to make.

Region

American oak (Quercus rubra): Found in America’s Midwest, American oak tends to be heavier, denser, less porous, less tannic, and more pronounced in vanilla and coconut flavors. American oak is usually used for big, bold reds like Zinfandel or Grenache.

French oak (Quercus robur and Quercus sessiliflora): Mostly found in Central France, French oak tends to be more subtle, more tannic, and promotes more oxidation. Lighter reds such as Pinot Noir are usually aged in French oak, as well as any wines made in a French style.

Side note: “French oak” refers to species that actually grow around Europe, most notably in Hungary and Romania. Winemakers may use Hungarian oak for its similar subtle flavor but lower price point.

Size

Barriques: A standard-sized barrel, also known as a Bordeaux barrel. These will often impart significant oak flavor due to their smaller size. A barrique can hold approximately 225 liters (59 gallons) of wine.

Pièces: Also known as a Burgundy barrel, these are larger than a barrique and therefore impart less oak flavor. Most Pinot Noirs and Chardonnays are aged in these barrels. A pièces can hold approximately 228 liters (60 gallons) of wine.

Foudres: Very large oak vats that can hold up to 4,550 liters (1,200 gallons) of wine. Due to their size, very little oak flavor is imparted. Châteauneuf-du-Pape and other Southern Rhône reds are usually aged in foudres.

Toast

Light, medium, and heavy toast: Wine barrels are exposed to heat as part of the coopering process. The longer the barrel is exposed to heat, the more “toast” it has. The heavier the toast, the stronger the flavors of smoke, roasted coffee, and butterscotch. Heavily toasted barrels are usually reserved for fortified wines like Sherry, Cognac, and Port.

Number of uses

New oak: Barrels that have never been used are considered “new” and will impart significantly stronger flavors than second use or neutral. Big, bodacious Cabernets and French wine

Second-use oak: Barrels that have been used a second time but still possess a noticeable oak flavor.

Neutral oak: Barrels that have been used three or more times and are considered “neutral” in flavor. Neutral oak will still allow oxidation though little flavor will be imparted in the wine. Lighter-bodied red wines and white wines are typically aged in neutral oak.

Fermenting vs Aging

On a final note, it’s important to know there’s a difference between fermenting a wine in oak and aging a wine in oak. If you were to do both – to ferment and age a wine in oak – you would end up with less oak flavor than if you fermented in another vessel and aged the wine in oak.

As wine ferments in oak, the active yeast also interacts with the oak. When the wine has finished fermenting, the dead yeast (or lees) are removed from the wine so it can begin aging. Much of the intense oak flavor ends up leaving right along with the lees.

Olivia is a Washington-based freelance writer with a Level 2 Award in wines from the Wine & Spirit Education Trust. She has a passion for all things food, wine, and travel, though her heart belongs to the Pacific Northwest. When she’s not sipping on a glass of Washington Cab., she’s usually bikepacking, crocheting, or chillin’ in the sun with her dog Tater.

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Website: liveatslocal.com