What does the term "appassimento" refer to in winemaking?

The term "appassimento" refers specifically to the process of drying grapes before fermentation. This technique is traditionally used in various Italian winemaking regions, particularly for making wines such as Amarone della Valpolicella.

In this method, grapes are harvested and then laid out to dry for a period of time, during which they lose moisture and become concentrated in sugars and flavors. This results in wine that is richer and more complex due to the concentration of the grape's characteristics. The dried grapes often exhibit higher sugar levels, which can lead to a wine with higher alcohol content and a fuller body.

The other options describe different aspects of winemaking that do not relate to the specific drying of grapes. For example, fermentation, barrel aging, and harvesting methods are key processes in winemaking, but they do not involve the specific technique of appassimento, which is focused purely on enhancing the grapes before they undergo fermentation.