Best Lab Equipment

Here are some more information for Alcohol Grape Refractometer:

Are My Grapes Ready to Harvest?

This is the time of the year that I keep hearing the question
"When do I harvest my grapes?" Or sometimes the question is
phrased "Are my grapes ripe yet?" And then there's the "Are they
ready yet?"

Yes, it's that time of the year when grapes are turning color
and homeowners are thinking about when their grapes will be
harvested. But many homeowners think that when the color turns,
the grapes are ready to eat. They pick a few colored berries and
pop them in their mouths only to find that there is very little
flavor and a puckering feeling hits their pallets.

Just because the color has turned on your grapes, it doesn't
mean they're ripe. Generally speaking, grapes need one to three
weeks after turning color to be considered ripe for harvest. But
this time frame is dependent upon many factors including the
variety, what the grapes are to be used for, and environmental
conditions like the weather.

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.

There are many fine books on growing grapes. If you want more
information on how to grow grapes in your backyard or garden you
can find my selection of suggested books at:
http://www.ristcanyonvineyards.com/grape_growing_books.html

About the Author

Thanks for visiting!