Oak barrels are used by a winemaker to
impart complementary flavors and aromas to a wine. Barrels are toasted
at various levels from light to medium to heavy, and will be selected,
to suit a particular grape variety or style of wine. Additional flavors
can also be gained from the complex interaction with yeast 'lies' (or
'lees'), the yeast sediment which will be in contact with the wine.
Barrels are a convenient container in
which to store a wine, as the subtle exchanges with oxygen, moisture and
alcohol help the wine to evolve from the youthful 'green' to more
complex and mature flavors. Many different types of oak are used in the
winemaking process, with white oak being the most common. French,
Hungarian, and North American oak are the best-known species used, with
each one having slightly different attributes. Just as vines and grapes
are distinctly individual when grown under different conditions or
areas, so are oak trees.
Very few wineries have their own
cooperate, preferring to rely more often on purchasing barrels that have
been carefully milled, cured and toasted. It is an expensive business
and requires a huge investment to be made by the barrel supplies.