How do we know when it's time to pick our grapes? The most important day of the year is the day we pick because it determines the kind of wine we’ll make from those grapes.
We start with our senses of sight, touch, smell, and taste. We want our grapes to be rich in color, not green. A ripe grape will crush easily, but not be shriveled. A ripe grape is plump, thickly juicy and smells good. It's a balance between sweet and tart. We also look for ripe seeds, which are brown.
It's good to use our senses but it's also important to measure. We measure sugar content, pH, and acidity level. Grapes are mostly water and sugar that will ferment to make wine. Brix is a term used to measure the sugar content of grapes. Brix is measured in the field with a refractometer.
We now know about sugar and how to measure it. Next, we measure PH. As our grapes ripen and the sugar rises, the pH will rise too. Grape juice is full of natural acids, which lend important qualities to wine. Every time we measure Brix we also measure acid levels. In a way, they're opposites; as the Brix goes up, the acid levels go down.
Our results should fall within certain ranges for Brix, PH, and acidity. When our grapes get close to those ranges, we go pick a sample. We sample about 100 grapes from both sides of the vines, high and low, in sunny areas and shaded areas, and pick from different parts of each cluster. We squeeze our juice into a cup and take our measurements. If they are within range, we pick on the next best available day!