Among all wineries oak is a key ingredient and every winery has their own idea on how that ingredient is and should be used. As with many ingredients there are different production methods, uses, types, producers, and of course different grades of quality. It would take a long time to break down what all these variables are and what they mean to us. For starters we will look at French barrels vs. American barrels and how they are different.
There are many different sources for the oak used in wine barrels; you can find oak producing forests in France, America, and others not as popular such as Hungary, Spain, and Austria. In America we get most of our oak from Minnesota. However, oak producing forests stretch from Pennsylvania in the North East through North Carolina, Tennessee, Kentucky, Missouri, and into Arkansas and Mississippi in the south. There is even an oak forest in Oregon that was used for wine barrels; however, after many trials it became apparent that the extreme hard oak of Oregon would be better suited for furniture and other construction purposes.
The forests in France that are producing oak for barrels have been around since the shipbuilding days of Napoleon. Five of the primary forests areAllier, Limousin, Nevers, Trancais and Vosges, which are all controlled by the State Government in France. Aside from the age of the forest and the controlling body, a major difference between American oak is the length of the growing season. The growing season dictates the grain size of the wood. The tighter the grain the less oxygen ingress will occur while the wine ages. A tighter grain not only means a less porous wood, which ensures a watertight barrel, but releases oak flavor to the wine more slowly. The shorter the
Cross section showing the wide grain of Oregon White Oak
growing season in America makes for tough, coarse, loosely-grained wood, that imparts strong flavors more aggressively and uptakes oxygen a little quicker.
We also get a variety of flavors from American oak and French oak. American oak gives off flavors of vanilla, spice, coconut, and even custard. Some say that American oak can also impart a harsh or raw flavor. However, American coopers started practicing more French barrel making techniques and the flavors improved. America is now air drying the oak rather than using a kiln to dry, and have also started to split the oak into staves rather than using a saw. Splitting helped rupture less xylem cells that contain the flavor compounds for the oak, and lead to a longer more smooth integration of flavor to the wine.
Cross section showing the tighter grain of French White Oak
French oak can impart flavors of butterscotch, elegant vanilla, cedar, and caramel. The French techniques and oak have helped make a more elegant flavored and softer impacting wine barrel. That is why a majority of winemakers prefer French oak. With advancements from American coopers, the high price of French oak, more research into other white oak producing forests and additional types of oak additives for wine, other oak products are catching up quickly to the quality the French have had for years.