Capturing a grape's sweet essence at its peak is the key to making a delicious and balanced bottle of wine. Long ago, a seasoned winemaker had to rely mainly on the senses of touch and taste to tell when grapes on the vine were ready to be transformed into wine. Today, these same senses, along with a little help from a handy wine-making tool, can help you harvest your wine grapes properly.
Touch the grapes to test them for ripeness. Most fully ripened grapes will not be overly firm to the touch.
Extract the grape juice for testing. Pick a handful of grapes and squeeze the fruit with your hand. Capture the juice in a clean container for testing.
Strain the juice through a nylon straining bag to remove any large particles, capturing the juice in another clean bowl.
Use a hydrometer to test the sugar levels in the grape juice, following the instructions that came with the device. The sugar levels should be approximately 22 Brix, which will yield a potential wine alcohol level of 11 percent.
Taste the fruit. The grapes should have an overall sweet taste to them with a tart finish.
Harvest the grapes. If the grapes pass the sugar levels and taste tests, it is time to harvest them for wine making. Cut the grape clusters from the vine with a sharp knife or pruning shears.
Clean the grapes. The fruit should be cleaned of all debris, such as insects, leaves and stems. Removal of the stems is paramount to avoid a bitter-tasting wine.
Inspect the grapes. Only fully ripe and healthy-looking grapes should be used. All rotten or misshapen grapes should be discarded.