What's the difference between French and American oak?
It's all in the fibres, which impact wine flavour, barrel prices and even how the vessels are constructed.
Virtually all wood used for wine maturation belongs to three species of white oak, all of which have the advantage of being extremely water-tight relative to most other lumber. Two species, Quercus petraea and Quercus robur, generally are sourced from French forests (in some cases, Eastern Europe and Portugal), while Quercus alba, a.k.a. American white oak, grows mainly in the eastern United States and southern Canada. All three tend to improve wine flavour when used judiciously, adding subtle vanilla and spice accents, enhancing texture and even contributing tannic backbone for longevity.
Anatomically speaking, French oak is slightly more porous, and that's a key difference. This means it must be split along the plane of vascular tubes that run parallel to the trunk in order to create staves that make up the barrel. American oak, on the other hand, can be sawn without sacrificing its water-tight character. Consequently, American-oak barrels cost less to make.
Generally, French oak is thought to impart a subtler influence and smoother texture, which is nice most of the time, while American oak is bigger on vanilla flavour and astringent tannins. American oak also sometimes tastes ever-so-slightly of coconut, which is a giveaway to a trained wine taster.
But such differences can be obscured by other factors, most notably the level of toasting or charring given to the barrel's interior surface.
While French oak is considered the gold standard by winemakers in such places as Burgundy and Bordeaux and for use with such white grapes as chardonnay, American oak is preferred by some producers of fuller-bodied reds in New World regions. It's also widely used in Rioja, the heavily oak-influenced wine from northern Spain.
Beppi Crosariol will be among the hosts of a luxury two-week journey through Burgundy, Beaujolais and the Rhône Valley next August, along with other Globe journalists, as part of The Globe and Mail French River Cruise. For details, visit tgam.ca/cruise.