Few things better represent the art of winemaking more than the image of oak wine barrel racks inside a picturesque château, as they lovingly age the sweet juices that will one day be poured into our glasses. It’s an Old World image that reminds us to respect the timeless task of winemaking. While there are many types of wood barrels in which wine is aged, this piece will focus on oak -- from American to Slavonian and everywhere in between. Here, I will explore the life cycle of an oak barrel from its cool forest origins, to its glory days as a vessel for aging wine, to its retirement. This article will be most enjoyed with a glass of Silver Oak Napa Valley Cabernet Sauvignon, aged for twenty-four months in the delightfully coconut-driven American Oak.
Why oak?

In short, oak acts the good parent. It calms the adolescent wine down, matures it, and imparts complexity and depth. Wine aging in oak barrels gradually takes on the character of the wood and imparts its tannins, adding to the wine a combination of flavors and aromas such as vanilla, spice or tobacco. These flavors and aromas depend on the tightness of the wood grain, the tannin content, and the oak’s origin. Traditionally the majority of oak used in wine barrels comes from century-old trees in France, the United States and, to a much lesser extent, Hungary.

The heritage of French oak derives from forests planted in the Napoleonic era to equip France with the lumber needed for shipbuilding. Today it is overseen by the French government. “Overseen” is perhaps too weak a word. The French forest service meticulously manages their forests, culling weak trees and clearing undergrowth that competes with the trees for nutrients. The sale of the oak is conducted by auction process, which partly explains the high price of French oak. France’s forests are clustered in central France -- Limousin, Allier, Nevers, Troncais and Vosges.American oak certainly lacks the pedigree of French oak, but its market share is on the rise. Aging your American wine in American oak is a truly patriotic move that will help the country to further establish itself as a preeminent maker of fine wines.  Of course, there’s always the middle ground to be found in Slavonian oak. Sure, it’s European, but it doesn’t carry the cache of France. Perhaps you can taste the difference?

The Humble Beginnings of a Wine Barrel

The wine barrel itself is truly a simple concept – a handmade wooden container meant to store 60 or so gallons of wine for a period of months or years. But to call it simple is to trivialize the craftsmanship and sweat that goes into its construction, and the benefits, nay, necessity, of handmade construction helps explain why “Cooper” is still a job title in the 21st Century.

It starts with the fallen oak tree, sawn into logs shortly after felling. Logs are then hand split to preserve the wood grain – this intact wood grain is essential to a barrel’s impermeability. The inherent spaces between these wood grains vary based on the region from which the oak tree hails. French has tighter grains, which impart softer flavors. America has wider grains, which impart stronger flavors. From there, the split and planed log lengths are left outside, open to the elements, and naturally aged outdoors. Like camping does for young children, the time outdoors adds character to the wood.

After the natural aging process the cooper partially puts the barrel together. Individual staves are made and affixed to the inside of two or three barrel hoops.

Getting Toasty

Next comes perhaps the most important part of the process, the toasting. The partially constructed barrel, looking at this point like a wooden skirt, is exposed to fire as a way to mitigate the worst instincts of the wood’s tannins, add further complexity to the flavor, and make the wood a little easier to shape. After the toasting, the remaining barrel hoops are put in place, and the barrel head is inserted into the groove, or “croze,” cut into the inside ends of the staves. At this point the barrel is tested for impermeability – a leaky barrel is no good to anybody – and finished with sand papering.
Father Time and Your Wine

The next and most important for wine lovers, is the aging process. Finished new barrels are shipped off to wineries and filled with wine. Over the next several months or years they slowly work their magic, occasionally being opened by the winemaker for tasting. This helpfully adds a little bit of oxygen into the equation. The same is true for the cork in your bottle. Those tiny sips of air go a long way in encouraging the wine to develop new and exciting flavors. Chocolate-covered bacon? Curried chives? It’s all within the realm of possibility.

Barrels famously have the potential to last decades, but the truth is that their usefulness for most wine largely diminishes after 3-5 years when the wood, giving away all its flavor, turns into a neutral agent. This neutrality is actually useful for some winemakers. Some winemakers, for instance, blend wine from old and new barrels. The neutral oak softens the wine without taking attention away from fruit flavors. Other winemakers prefer flavorful oak barrels. They feel that the oak packs just the right caramel and vanilla punch to lift fruit flavors from the wine while inviting rich and complex tannins. 

And so, the great wine barrel swap begins. Some winemakers are after brand new barrels, while others want barrels that have been thoroughly used. It is also possible to shave away the inside layers of the barrel and re-char the newly exposed wood. But in my opinion, the flavors from the inner layers tends to be disappointingly less complex than the original.

Appreciating the Wine Barrel

The life of a wine barrel, from its origins in a misty French forest to its formative years in a cool cellar, truly makes one further respect the intricacy and mystery of winemaking. The fine craftsmanship and history involved highlights the dedication of those committed to producing fine product for the rest of us. So next time you find yourself touring a winery or just enjoying an oaky offering, take a minute to appreciate the centuries-old year tradition that begins with a sapling and ends in your glass.