|
The grape variety has a lot
to do with how quickly the grapes will ripen. Varieties are classified
as early, mid-season, and late depending on how many days it
takes for the grapes to go from full bloom of the flowers to
harvest ripeness (Usually compared to the Concord variety). It
should be obvious that early varieties will ripen fast and be
picked much earlier than late varieties. If you grow a variety
that is considered late in an area with a short growing season
of less than 170 days, the grapes will never get totally ripe.
What you are going to use the
grapes for goes hand-in-hand with the variety. Each variety has
been bred for specific uses. Some are table grapes. These are
used for eating. There are jam and juice grapes. And then there
are wine grapes. Each are harvested by sugar content and acidity.
Table grapes don't need as much
sugar as wine grapes to be considered ripe. They usually reach
between 16 and 18 percent sugar before they are ready to harvest.
For the homeowner with grapes in the backyard or garden this
is hard to measure. But since you are going to eat them, you
only need to taste the grapes to determine if they are ready.
The flavor components are as important as the sugar level of
the grapes. When they get to the point where you think they taste
good, then pick them.
Be sure to taste more than one
berry to determine this though. Not all grape berries are ripe
at the same time. Berries in different parts of the cluster ripen
at slightly different times. Clusters don't all ripen at the
same time either. Clusters in the sunshine ripen quicker than
those that are shaded. Clusters towards the base of the shoot
ripen earlier than those towards the tip of the shoot.
Wine grapes need more sugar
to produce a higher alcohol content when fermented. Grape growers
like wine grapes to reach 20 - 24 percent sugar ideally. Here
again, this is variety dependent. Acidity is also important when
considering the ripeness of wine grapes. Too high acidity will
make the wine taste acidic and bitter and too low will make the
wine flat.
If you are growing grapes to
make wine, you might want to invest in an instrument called a
refractometer to measure the sugar content of your grapes. This
tool makes it easy to find out how much sugar is in one or more
berries. The juice of the berries is squeezed onto the refractometer
plate, the plate is closed, and then by holding the instrument
towards the light you can look into the eyepiece and see what
the sugar reading is.
A less expensive means is to
use a hygrometer. You need at least 50 berries to determine the
sugar content by this method though. Hygrometers are more accurate
than a refractometer and that's the trade-off. The hygrometer
is floated in the grape juice obtained by squeezing the berries
and the sugar content is read off the scale in the neck of the
hygrometer.
Acidity can be measured by the
titration method. But this is more in the realm of the chemist
than the hobby grape grower. Because the pH of the juice is related
to the acidity, it is more convenient for the small grower to
use a portable "pH pen". A pH of between 3.00 and 3.55
generally indicates that the acidity of the grapes is in the
for making wine. This also will depend on the variety.
The seeds of the grape berry
are also an indication of ripeness. If the seeds are green or
light tan, the grapes are usually not ripe. Ripe grapes have
brown, mature seeds. Along with this, the ease with which the
berries can be pulled off the cluster also can indicate degrees
of ripeness. Ripe grape berries can be pulled from the cluster
with little resistance.
Birds, raccoons, squirrels,
and other wildlife that like to eat grapes can also be an indicator
that your grapes are ripening and ready for harvest. These pests
will harvest and eat your grapes
as soon as they are ripe. Of course, you don't want to allow
them to eat your grapes before you have a chance to harvest them.
Bird netting and fences are needed to keep these pests at bay
and allow only you to have the pleasure of your grape crop. |
Refer
