The scientific approach to wine making had begun. It would solidify
what European vintners knew from experience and give the foundation
to new growers around the world, primarily in California and Australia
where world-class vintage wines are now produced. The steps for making
red wine and white wine are similar, an oenological theme and variations,
as both red wine and white wine are made by crushing and fermentation.
The treatment varies to produce either delicacy or robustness.
At every step of this process,
the artistry of the vintner is called upon. Gentle handling is necessary
to produce a bottled wine of full varietal flavor and character.
Crushing and Extracting
the Juice that Will Become Wine
The more fragile whites, such as
Chardonnay, are picked at night when the acids are the highest - in
the day, heat and sun reduce acids and draw out sugars. Red wines, on
the other hand, get their acids from the grape skins and don't need
such delicate handling.
Each part of the grape possesses
different compounds and qualities that combine to make a good wine.
The interior pulp is, of course, almost pure liquid. The skin has
much of the pigment that will color wine as well as tannins, acids
and compounds that become aroma and taste. A delicate white wine would
be overpowered by too much of the these compounds, while a red wine
derives its body and flavor from the judicious use of these elements,
so the pressing is effected in two stages.
The first press, called the free
run, comes from the middle of the pulp. It is the clearest, most
easily pressed liquid, and is gotten with very little pressure. After
this is pressed, a heavier pressure is exerted to get the juice from
within the skin. A vintner determines the amount of pressure brought
to bear in the second pressing.
Fermentation of Grapes
Once again, the process of fermentation
varies between the red wines and white wines. With white wine, the
clear, juices are pumped straight to a fermenter. The juice of the
initial pressing is fermented separately from the skin pressing. Red
wine is not separated into separate pressings when fermented, but
goes through the process with both elements mixed together. The hearty,
robust flavors of red wine come from this togetherness as the fermentation
process extracts more tannins, flavors and color from the skin.
The fermentation process begins
with the addition of yeast to the juice. Yeast consumes sugar which
then converts into alcohol and carbon dioxide. It also liberates molecules
within the juice, bringing out the flavor of the grape itself.
The grapes may be fermented in
either an oak barrel or a stainless steel tank. Stainless tanks provide
stable temperatures and produce crisp, clean white wines. Oak barrels
contribute tannins of their own and render a fuller-bodied wine with
more complex overtones. White wines are fermented for 4 to 6 weeks
at about 60 degrees F while red wines are fermented between 65 and
80 degrees for 4 to 14 days. A sweet wine is produced by stopping
the fermentation process before all the sugar has been consumed by
the yeast. Alternately, a vintner may add sweet juice after the fermentation
Once in the barrel the wine is
kept in barrel aging rooms with controlled humidity, heat and light
settings. Wine does not like bright light. While a human winces and
looks away from bright light, wine will change its character.
There may be a second fermentation
called malolactic fermentation. This is to convert the tarter malic
acids to sweeter lactic acids. These wines gain a subtle flavor during
the aging process.
Racking and Fining Wine
This is the process of clearing
the fermented wine of any solid particles of yeast or grape. The wine
is gently decanted from the barrel, leaving the sediments behind.
The wine may then be fined, a process in which a substance is added
that draw particles to it. Natural fining agents include egg whites,
milk protein and isinglass. The wine may then be filtered, though
filtering removes not only every last particle, but some of the flavor
of the wine. Many wines are unfiltered to retain a full flavor.