The
use of oak in wine plays
a significant role in winemaking
and can have a profound
effect on the resulting
wine, impacting the color,
flavor, tannin profile and
texture of the wine. Oak
can come into contact with
wine in the form of a barrel
during the fermentation
or aging periods. It can
be introduced to the wine
in the form of free floating
oak chips or as wood staves
(or sticks) added to wine
in a fermentation vessel
like stainless steel. Oak
introduced in the form of
a wine barrel can impart
other qualities to the wine
through the process of evaporation
and low level exposure to
oxygen.
Many
winemakers choose to ferment
their wine in oak as oak
barrels tend to soften the
wine and impart characteristics
that improve the flavor
of the wine. The oak wood
used for these barrels is
mainly derived from France
and the United States although
there are many countries
from which oak barrels come
including Spain, Hungry,
Austria, and many more.
American oak passes on prominent
characteristics to the wine,
while French oak tends to
lend more subdued characteristics.
Each type of oak imparts
notes of vanilla,
caramel, cream, clove, smoke,
and fresh cracked black
pepper. Another
important trait passed over
from the oak is the tannin
found in the wood –
tannins from American oak
are sharp while French oak
provides more subtle tannins.
Some
other differences to note
are that American oak tends
to be more intensely flavored
then French oak with more
sweet and vanilla overtones
due to the American oak
having two to four times
as many lactones. Winemakers
that prefer American oak
typically use them for bold,
powerful reds or warm climate
Chardonnays. Besides being
derived from different species,
a major difference between
American and French comes
from the preparation of
the oak. The tighter grain
and less watertight nature
of French oak encourages
coopers to split the wood
along the grain rather than
saw. French oak is then
traditionally aged or "seasoned"
for at least two years whereas
American coopers will often
use a kiln-dry method to
season the wood. Long periods
of outdoor season has a
mellowing effect on the
oak that kiln-dry methods
have difficulties replicating.
The sawing, rather than
splitting, of American oak
also enhances the differences
between the two styles due
to the rupture of the xylem
cells in the wood which
releases many of the vanillin
aromatics and lactones responsible
for characteristics like
the coconut notes.
The
length of time that a wine
spends in the barrel is
dependent on the varietal
and style of wine that the
winemaker wishes to make.
The majority of oak flavoring
is imparted in the first
few months that the wine
is in contact with oak but
a longer term exposure can
effect the wine through
the light aeration that
the barrel allows which
helps to precipitate the
phenolic compounds and quickens
the aging process of the
wine. New World Pinot noir
may spend less then a year
in oak. Premium Cabernet
Sauvignon maybe spend two
years. The very tannic Nebbiolo
grape may spend four or
more years in oak. High
end Rioja producers will
sometimes age their wines
up to ten years in American
oak to get a desired earthy,
vanilla character.
These
may not seem like important
factors at first, but as
you explore the world of
wine you’ll begin
to notice subtle differences.
California Chardonnays are
often aged in toasted oak
for a long period of time,
which imparts the intense
vanilla flavor that many
have grown to love. But
the fruit flavor drops off
almost as soon as the wine
is swallowed, a problem
which many call “overoaking”
a wine. Meanwhile, Chardonnay
wines from Chablis in Burgundy
have subtle vanilla flavors
from shorter barrel storage,
which allows the wine a
crisp finish with fruit
flavors that linger in the
back of the throat long
after being swallowed.
White
wines that are fermented
in oak often have a pale
color with an extra silky
texture. White wines that
are fermented in steel and
then matured in oak will
have a darker coloring due
to the heavy phenolic compounds
that are still present.
Flavor notes that are common
descriptions of wines exposed
to oak include caramel,
cream, smoke, spice and
vanilla. Chardonnay
is a variety that has very
distinct flavor profiles
when fermented in oak that
include coconut,
cinnamon and cloves notes.
The "toastiness"
of the barrel can bring
out varying degrees of mocha
and toffee notes in red
wine.
While
oak aging is time honored
and respected some wine
lovers prefer wines that
are fermented in steel barrels.
These wines often have a
more fruit-forward flavor
and can be more true to
the actual grape flavor.
In these wines, we may feel
slighted by the minimized
tannins and lack of barrel
spices, but these wines
exude a more true expression
of the grape. Oak aging
can be seen as a more old
world practice while steel
aging will tend to be seen
more in the new world as
in New Zealand and Australia.
One is not necessarily better
than other. It is all a
matter of preference. If
you prefer a little more
complexity and like more
tannic wines go for an old
world wine that is oak aged.
If you like a more fruit
forward wine then stick
to a steel aged wine from
South America or New Zealand.
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