Wine barrels are instrumental in creating the wine you drink. Usually oak is used for those barrels, and for good reason. Other woods have been used, such as cherry, walnut, chestnut and pine, but by far it is oak that gives the best results. For some reason oak plays perfectly to wine. It makes the complex. It gives the wine depth. Of course some more delicate wines still require other woods, but for the most part it is oak that is used.
Oak barrels are made by intense sourcing. The reality is that oaks growing in one area of the world are vastly different than oaks growing in another. Usually, the most sought-after sources are from US-locations in Iowa, Minnesota, Missouri, Ohio, Kentucky, and France-locations in Troncais, Vosges and Nevers. The colder climates in these areas force trees to grow slowly. It is this time that pushes them to be the perfect vessel for wine making. As you probably know, trees form rings within their trunks. In warmer climates, these rings grow quickly and are loosely bonded within. In cold climates, the opposite is true; the rings grow slowly and are tightly grained together. It’s this tightness of grain that gives these trees the ability to imbue their essence into the wine they hold.
An oak tree usually is never harvested until it reaches 100-years old. A cooper, or barrel maker, will hand-split the wood carefully. It is then left outside to dry for two more years. It is here that it experiences the elements- sun, rain, etc. in an effort to pull out the tannins. Tannins, or polyphenols, can be harsh and acidic. In moderate levels they give wine its distinct acidity but higher levels would produce an undesirable result.
Coopers have a difficult job. They have to take wood and form it into a barrel, no small task. Staves, or pieces of wood, are heated over fire to make them more pliable. The cooper shapes them using chains and winches and uses rings that are hammered into place. The rings hold the wood together and the cooper seals the seams. A good cooper can produce about one barrel a day, and that barrel will be used for about 5 years by a winery. After its initial 5-year lifespan, it is sold to smaller wineries.
The barrel has to be held over intense heat throughout the procedure. This is what not only allows the cooper to bend the wood, but it also caramelizes the wood’s sugars, that eventually will give the barrel its vanilla, toasty flavor. On average an American-sources barrel costs around $400 while France-sources can cost upwards of $900.
The next time you're drinking wine, remember the work that went into building its barrel. The vessel is what gives it its flavors and creates its body.