As the grapes ripen, sugar levels increase and acid levels go down.
Wine makers target the best balance between sugar level and acidity to make wines that are also well balanced. Picking too early gives low alcohol, high acid wines, but also herbal "green" flavors.
When you harvest too late, you get high sugar (high alcohol) and low acidity "flabby" wines. Overripe grapes produce "plummy, jammy" notes. Depending on the winemaker's wine style objective, and weather, he may choose to harvest in the early ripeness stage. For cabernet sauvignon this gives red fruit characteristics "cherry, strawberry". At later ripeness, flavors change to black fruit, like plum and blackberry.
We use a refractometer to measure sugar level. Two weeks ago the sugar level was 15 BRIX (= sugar %), and yesterday we measured 21 BRIX. However, the acidity level is still too high to make a well balanced wine.
We'll give our grapes a little more time....