According to the official journal of the European Community (L179), wine is:
“...the product obtained exclusively from the total or partial alcoholic fermentation of fresh grapes, whether or not crushed, or of grape must.”

The level of grape maturity at harvest is one of the most decisive factors in determining wine quality. It is the result of all of the complex physiological and biochemical phenomena whose proper development and intensity are intricately related to environmental conditions (including vine variety, soils and climate) and fixed when the grapes are harvested.

From the winemaker’s point of view, the questions that need to be answered are:

• When exactly is a grape ready to harvest?
• How can we forecast and hence prepare for harvest date?
• How should harvest itself be carried out?

In order to answer these questions, the winemaker must have a good understanding of grapevine berry composition and development.