By Rai Cornell

You know how different grapes, terroir, and aging processes affect the flavor of the wine in your glass. But do you know what’s up with all those gorgeous oak barrels that hang out in classy wineries?

 

From French oak to American, barrels to chips, the wood that touches your wine imparts a ton of character before that luscious liquid touches your lips.

 

Here’s the low-down on oak’s role in shaping the perfect vintage.

 

America v.s. France

Oak is the gold standard when it comes to making wine barrels. However, not all oak is the same. Most of the wood used to make wine barrels comes from two countries: the United States and France.

 

Due to dramatic climate differences between the two countries, American and French oak trees grow differently. While American oak grows with a wide grain, French oak grows with a tighter grain pattern.

 

True to America’s bold and assertive culture, the wide grain in our home-grown oak barrels means the wine and wood are able to interact more during the aging process. When the wine hits your palate, you’ll notice hues of vanilla, sweet spice, coconut, dill, and even cream soda!

 

On the other hand, the tighter grain in French oak leaves less room for wood-wine interaction, so the flavors each barrel imparts on your wine are more subtle. As the French say, un petit peu.

 

French oak flavors are reminiscent of savory spice, roasted coffee, and dark chocolate, and result in a more elegant mouthfeel.

 

Grapes can be rather picky about their oak and take sides between nations. For example, Cabernet Sauvignon, Chardonnay, and Pinot Noir only reach their peak of flavor when stored in French oak – like this 2007 Chardonnay Alto Adige and this 2016 Ginglinger Pinot Noir.

 

On the other hand, grapes like Syrah and Merlot are non-partisan and do equally well in barrels made from either American or French oak.

 

More of an Art Than Science

The beauty of wine and winemaking is in the complexity of factors that contribute to the end result. While it may seem easy enough to choose between American or French oak to get the desired taste for your wine (American = bold; French = subtle), it’s far more complicated than that.

 

Reuse, Recycle, Reduce

As wine barrels are used again and again to age new batches of wine, the flavor influences they have on the wine inside diminishes.

 

Many winemakers will age wine in the same barrels for only a handful of batches before retiring the lovely wooden artifact. Other winemakers will use fresh wine barrels to get a specific flavor into one type of wine, then use the somewhat flavor-depleted barrels for other vintages that require less oak influence.

 

Toast!

Don’t raise your glass just yet - we don’t mean that kind of toast. Toasting is the process of heat-treating the inside of a wine barrel before adding the wine.

 

Toasting oak barrels does two key things. First, it reduces the bitterness of the tannins found in oak. Second, toasting releases the wood’s natural vanillin content (which, as you might guess, adds notes of vanilla to the stored wine). A light toast will contribute little to the final taste of the wine, while a heavier toast will bring out the wood’s hidden flavors and add tons of character.

 

Size Matters

Think back to high school geometry. Remember that whole thing about volume being cubic while surface area is squared? Yeah, neither do we - but stick with us here.

 

When wine is stored in a large barrel, the ratio between the cubic volume of wine in the barrel and the inner surface area of the oak barrel is rather large. In other words, there’s a lot more wine and not a whole lot more surface area when compared with a smaller barrel.

 

As the wine interacts with the oak barrel, the characteristics of the oak barrel are diluted in the large volume of wine. On the other hand, with a small barrel, the traits of the oak barrel are mixed with a smaller volume of wine and are then able to stand out more.

 

Winemakers looking to impart more of the oak’s flavor profile on their wines will use smaller barrels while winemakers looking for a more subtle influence will use larger barrels.

 

Pass the Chips, Please

Wine barrels are expensive. In fact, high-end barrels can cost $900 apiece or more. Rather than using genuine oak barrels, many vintners age their wines in stainless steel tanks. However, steel is not wood – it has no tasty little pores that wine can explore and use to pick up flavor.

 

To cut back on cost but still get the same great influence that oak barrels offer, some winemakers are experimenting with adding wood chips to the mix.

 

The pre-toasted bits of oak chips are added during the aging and fermentation process, then strained out when the wine has absorbed enough of the wood’s personality. When done correctly, the end result is a wine with flavors that mimic those of barrel-aged wines.

 

However, there’s debate over the effectiveness and quality of the process. Some die-hard oenophiles believe barrel-aging is the only true way to impart oak’s glorious notes on a wine. And they may be on to something.

 

Studies show that even quality wines made with oak chips have a different chemical composition than wines aged in barrels. In molecular terms, the variation is quite small and inexperienced wine drinkers may not notice the difference between wine that has spent time with oak chips versus oak barrels.

 

If you’re a seasoned wine lover, though, your adept palate may pick up on the penny-pinching trick. The only way to find out: drink more wine!

 

Then come back and let us know in the comments below if you can tell the difference between barrel-aged or wood-chipped wine.