Grapes harvest. Farmers hands with freshly harvested black grapes.

Yes, it is the time of the year when grapes are turning colour and homeowners are considering if their grapes will be harvested. But many homeowners believe that when the color turns, the grapes are ready to eat. They select a few colored berries and pop them in their mouths only to discover that there’s very little taste and a puckering feeling strikes their pallets.

Ripe Grapes?

Just because the color has turned in your grapes, it does not mean they are ripe. Generally, grapes need you to three weeks after turning colour to be considered ripe for harvest. But this time frame depends upon many variables such as the variety, what the blossoms must be used for, and environmental conditions such as the weather.

The grape variety has a lot to do with how fast the grapes will ripen. Varieties are classified as early, mid-season, and late depending on how many times it takes for the blossoms to go from full bloom of the flowers to harvest ripeness (Usually in comparison to the Concord variety). It needs to be obvious that ancient varieties will ripen quickly and be chosen much sooner than late varieties. If you develop a variety that’s considered late in a place with a short growing season of less than 170 days, the blossoms won’t ever get totally ripe.

What you will use the grapes for goes hand-in-hand with the variety. Each variety was bred for certain uses. Some are table grapes. These are used for eating. There are jam and juice grapes. And then there are wine grapes. Each are chosen by sugar content and acidity.

Table grapes

Table grapes do not need as much sugar as wine grapes to be considered mature. They generally reach between 16 and 18 percent sugar until they are ready to harvest. For the homeowner with grapes in the backyard or garden this is tough to measure. But since you will eat them, you just have to taste the grapes to ascertain if they’re ready. The flavor components are as important as the glucose level of the grapes. When they reach the point where you think they taste great, then select them.

Make certain to taste more than one berry to ascertain this though. Not all grape berries are ripe at the same time. Berries in different areas of the cluster ripen at slightly different times. Clusters do not all ripen at the same time. Clusters from the sunshine ripen faster than the ones that are shaded. Clusters towards the base of the shoot ripen sooner than those towards the tip of the shoot.

More sugar

Wine grapes need more sugar to create a higher alcohol content when fermented. Raisin growers like wine grapes to reach 20 – 24 percent sugar. Here again, this is variety dependent. Acidity can also be important when contemplating that the ripeness of wine grapes. Too higher acidity will make the wine taste bitter and acidic and too low will make the wine level.

If you’re growing grapes to make wine, you may want to invest in an instrument called a refractometer to measure the sugar content of your grapes. This tool makes it effortless to discover how much sugar is in one or more berries. The juice of the berries is squeezed onto the refractometer plate, the plate is closed, then by holding the device to the light you’ll be able to look in the eyepiece and see what the sugar reading is.

A less costly means is to use a hygrometer. You need at least 50 berries to ascertain the sugar content by this process though. Hygrometers are more precise than a refractometer and that is the trade-off. The hygrometer is floated from the grape juice obtained by squeezing the berries and the sugar content is read off the scale at the trunk of the hygrometer.


Acidity can be measured by the titration method. But this is more in the domain of the chemist compared to hobby grape grower. Because the pH of the juice is linked to the acidity, it’s more suitable for the small grower to use a mobile “pH pencil”. A pH of between 3.00 and 3.55 generally indicates that the acidity of the grapes is at the for producing wine. This also will depend on the variety.

The seeds of the grape berry are also a sign of ripeness. If the seeds are green or light tan, the blossoms are normally not ripe. Ripe grapes have brown, mature seeds. In addition to this, the simplicity with which the berries may be pulled off the bunch can also indicate levels of ripeness. Ripe grape berries can be pulled in the bunch with minimal resistance.

Prenez note !

Birds, raccoons, squirrels, and other wildlife that like to eat grapes are also a sign that your grapes are ripening and ready for harvest. These pests will harvest and eat your grapes once they are ripe. Needless to say, you don’t wish to let them eat your grapes before you’ve got an opportunity to harvest them. Bird netting and fences are required to keep these pests at bay and allow one to have the pleasure of your grapes harvest.