The importance of a great cooper is essential to a unique final product.
Education
March 10, 2017

The importance of a great cooper is essential to a unique final product.

Cooperage—the process of making barrels—is an ancient craft that has changed very little in centuries and still requires the hands of an expert. These expert barrel-makers, or “coopers”, pay great attention to the construction of wine barrels, which are constructed using either French or American white oak  – although many will use a mix of both to better age their wines. Barrels generally come in one of two standard sizes: “Bordeaux” (225 liters / 59 gallons) or “Burgundy” (228 liters / 60 gallons).

Because the wood is the key factor in the quality of the finished barrel, coopers hand-select the best oak for wine barrels, often from old-growth European forests. French oak has long been the gold standard for aging premium wines due to its consistent fine-grained wood, although American White oak found across the Eastern US is gaining in popularity.

After the wood is selected, logs are hand split to preserve wood grain (an essential step in producing impermeable barrels) and the wood is naturally aged through exposure to air and water.  This natural aging process (called seasoning) can take years and serves to remove impurities that could eventually overpower the flavor of the wine.

After aging, lengths of wood known as staves are carefully cut and shaped. The cooper then assembles the staves inside a metal hoop that acts as a jig, an operation known by one of those wonderful French phrases: mise en rose, or “raising the barrel.” 

At this point, the staves are subjected to trials by both water and fire. The cooper seals joints by running a wet cloth over the staves and placing the partially constructed barrel over a fire, charring or “toasting” the interior to caramelize the wood sugars. The “toast” can be light, medium, or heavy—a decision the winemaker makes based on the style of wine they’ll be aging and the aromas they want the toast to impart upon it.

The wood, once almost as hard as a rock, is now malleable and can be gradually arched and tightened into the shape of a barrel.  Great precision is necessary to cut a groove called a “croze” into each stave, and barrel heads are carefully formed to fit the croze and create a perfect watertight seal.

At last, the cooper sets the barrel upright, fits the barrel heads into the croze, and completes the final “hooping” with a large mallet.  The barrel is tested for impermeability and, if it passes, is almost ready to be filled with wine.  This process to produce a single wine barrel from start to finish takes approximately eight hours of expert labor, almost all of it by hand.  

Modern wine barrels can be made of other materials—aluminum, stainless steel, or even certain types of plastic—but oak remains the first choice of the best winemakers due to the aroma compounds–often described as coconut, vanilla, buttered bread, cloves, caramel, or smoke—that it adds to the wine.

The tastes yielded by French and American species of oak are slightly different, of course: French oak is subtler, while American oak—surprise, surprise–tends to be a bit bolder.

To discover more about this behind the scene, follow our Instagram account @bordeauxwines. Every month you will discover more behind the scene moments and secrets that make Bordeaux wines unique.

Enjoy !  

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