This weekend,
our class paid a visit to Montalcino, a quaint town about an hour from Siena.
The intention of our visit was to understand a little more about the wine
making process and of course, to taste two of the wines particular to this
town, Brunello di Montalcino (picture to the right) and Rosso di Montalcino. Now, I am no wine tasting
expert, but even I could taste the difference between the two wines. The Rosso
was more ruby red in color and fruitier in taste, almost sweet. The Brunello
was slightly darker, more garnet in color and slightly more bitter, but richer
and fuller in taste.
Both wines are
made from the same varietal of grape, the Sangiovese Grosso. However, the
vinification of each wine constitutes the different tastes. The Brunello is
aged longer, required to spend at least two years in oak barrels and two years
in the bottle. It cannot be released before the fifth year after the vintage. The
Rosso, on the other hand, is ready after one year. Our class visited the La
Magia vineyard and took a tour of the cellars, but afterwards I still had
little knowledge of what changed during the aging process and why the wooden
barrels were so darn important.
The first thing
to understand is the difference between the terms “maturation” and “aging.”
Maturation is used to describe the changes in wine during bulk storage, where
wine can be exposed to air, while aging describes the changes from storage in
bottles under anaerobic conditions.
During
maturation, wine will change due to differences in temperature, humidity, and even
the size and type of storage container. The Brunello that we saw at the La
Magia vineyard was stored for three years in barrels made of oak. White oak is
used because it is practically water resistant. As the tree ages, the pores in
the rings of the tree become clogged with a type of cellular growth called
tyloses (seen on the left), which essentially restricts the flow of liquid. This is why other
types of wood are less effective in wine maturation, because without the tylose
plugs, the wine would drain right out of the barrel.
As for the
actual maturation of the wine, oak is important for two reasons. First, the oak
holds many volatile and nonvolatile components that can be extracted from the
wood while the wine is stored. Some barrels are even prepared through seasoning
and toasting beforehand to add certain flavors to the wine. Second, the oak
allows oxidation of the wine that will lead to enhancement of color and
decreased astringency.
Oak is composed
of cellulose, hemicellulose, lignins, and tannins. The barrels are usually
toasted before storage of wine because the lignins decompose with heat,
creating volatile phenols such as vanillin (vanilla aromas), eugenol
(clove-like aromas), and 4-ethyl guaiacol (smokey and spicy aromas). These
compounds can all be found in aged wine. Toasting the barrels also leads to
compounds like furfural, maltol, and cyclotene, which have characteristic sweet
and caramelized aromas. These all come from the breakdown of carbohydrates when
the barrel is heated. By seasoning and toasting barrels beforehand, winemakers
can control what sort of flavors their wines will take on during the maturation
process.
(Mike in the La Magia cellars)
While we have
all learned that oxidation can promote spoilage and free radicals, controlled
oxidation can positively affect the wine. Controlled oxidation can stabilize
the color, moderate the tannin content, and increase the development of intricate
aromas. Anthocyanins and tannins take the stage here. We learned in class that
anthocyanins contribute to the color of wine. At a low pH level, anthocyanins
appear more red in color. As maturation occurs, anthocyanins link with tannins
to create polymeric pigments, which aren’t as sensitive to discoloration as pH increases and
can produce richer and more intense colors. During this time, tannins can link
with other sugars and proteins, softening the astringency and adding a fuller flavor
to the wine. All of these combinations rely on oxygen and temperature, which
must be closely regulated in order to get the best product.
Oak maturation
is only used to produce full-bodied red wines with complex flavors and aromas.
Aging this way is not required for lighter and fruitier wines, which are
sweeter in taste and cheaper on the market. Putting any type of wine in a
barrel won’t make it better, either. A winemaker must assess the quality of the
grape before deciding whether a good product can be made through maturation and
aging.
For more
details, check out some of the webites below. Reading through them definitely
gave me a better understanding of the aging and maturation of wine, and
ultimately more appreciation for the product.
http://www.ansci.cornell.edu/plants/toxicagents/tannin.html
http://www.food-info.net/uk/colour/anthocyanin.htm
http://www.wineperspective.com/the_acidity_of_wine.htm
http://www.wineanorak.com/tannins.htm
http://www.extension.iastate.edu/wine/oak-aging-red-wine
http://www.fattorialamagia.it/EN/home.html
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