New Molecular Techniques to Identify Berry Quality Characteristics

Deciding when to harvest the grapes is one of the most important choices that a winemaker or vineyard manager has to make. Sugar level in the grapes is often used as a maturity index, but sugar level at maturity is variable depending on the climate of the region where the grapes are grown and, therefore, is an inadequate indicator by itself. Others use the sugar to acid ratio or the color of the seed as indicators of optimum maturity. However, many winemakers (and consumers) these days want more flavor in their grapes and wines. As a result, alcohol levels have been rapidly increasing in wines, since the desirable flavors seem to develop late in the last stages of berry ripening. Many people taste the berries to measure the flavor potential, yet this methodology is very subjective. Are there better indices for flavor and maturity? Can we get the flavors out of grapes without the high sugars and subsequent high alcohol? When is the optimum time to harvest the grapes? What cultural practices improve the quality and flavor of grapes? What are the desirable flavors and attributes that contribute to a great wine? There are many questions that remain unanswerable today, but there are new molecular tools that are providing new insights and answers to these questions.