[Information based on DipWSET D1 material]
Before getting started, make sure to check out my post on Flowering and Fruit Set.
A Brief Overview:
Ripening is the third stage of Grape Development. Starting from the top…
During grape berry formation—the first stage of Grape Development— malic and tartaric acids begin to accumulate, aroma compounds and precursors begin to form (also check out Aromatic Compounds post), tannins start to accumulate. But the grapes themselves are green and quite bitter—very little sugar has accumulated at this point.
Another interesting anecdote is that water flow is quite high during grape berry formation, but too much water and nitrogen (please also see Stuck Fermentation to learn about soil nutrients) can prolong this phase, as it will encourage green growth, not grape growth. So “mild” water stress is the way to go here.
Veraison is considered second stage of Grape Development. This is when grapes begin to change their color, skins become more supple, stretchy. But regarding the grape growth, it actually slows down. This phase is what many viticulturists refer to as a “lag phase.”
Now we can enter the third stage—ripening.
