|
 |
| The Course |
| From the grape to fermentation |
The grape harvest
This is the most important event of the year; the day of reckoning after twelve
months of hard work. It is not easy to choose the right moment for the harvest.
This depends, firstly, on the grape variety and the type of wine which is to be
made from it. Where variety is concerned the marker is the Chasselas table grape,
which is taken as a reference and usually harvested between the end of August
and the beginning of September. This starts what is known as the first stage of
the harvest, involving the various Pinots from which white wines are made, Traminer
and Chardonnay. Two weeks later the second stage begins. This is for other white
grape varieties such as Sauvignon Blanc, Muscat, Riesling and Sylvaner, as well
as the first reds, such as Cabernet Sauvignon, Merlot and Dolcetto. Two weeks
after that the third stage of the harvest brings in Barbera, Lambrusco, Grignolino,
Trebbiano and Sangiovese grapes.
These are obviously only rough indications
as there are differences between individual varieties and areas and from year
to year. The vinegrower's decision as to the right moment is even more variable
depending on the wine that he wishes to produce.
As grapes ripen there is a gradual increase in sugars
(which will be transformed into alcohol) and a resulting decrease
in acidity. The vinegrower's
decisions will depend on this. If, for example, the aim is to
produce a white wine, perhaps a sparkling wine, to be drunk
young, it will be need a certain amount of acidity which is
necessary to make it fragrant, so grapes are picked early which
also enhances bouquet and freshness.
If, on the other hand, the aim is to produce a major red wine
suitable for ageing, the wine will need to be high in alcohol
so that it will keep for a long time; in this case the harvest
will be done later so as to obtain higher sugar levels. A separate
issue is the production of wines made from overripe grapes or
dessert wines: in this case the harvest is postponed to allow
the grapes to dry out in order to concentrate the sugars.
In order to ascertain the right moment for the harvest sample
bunches are picked and sugar and acidity levels are measured
with a hydrometer and a refractometer. But with one ear cocked
for the weather forecast; wet grapes cannot be harvested because
the rainwater is bad for the
must (juice) composition. Recent research has identified
another element which is important to take into consideration
when deciding when to harvest the grapes, especially when the
grapes are to be used for red wine. This is the maturity or
'state of health' of the polyphenolics,
substances which are essential to the colour and structure of
red wine. The balance
of a wine is the result of a number of factors; it may, therefore,
be counterproductive to pick the grapes late in order to raise
the sugar levels if this delay has a negative influence on the
polyphenolics.
The most careful vinegrowers pick
the grapes by hand, using small containers, so as to carefully select the best
bunches and make sure that the grapes are not broken before thy arrive at the
cellar. Mechanical grape-picking systems may only be used on certain types of
terrain and with certain ways of training the vines. Even though they are continually
improving, especially in term of bunch selection, they do not guarantee the ability
to choose the best quality - something which only a careful eye can ensure.
|
|
