Which fermentation process is often used in the production of sweet wine styles like Sauternes?

The fermentation process commonly used in the production of sweet wine styles like Sauternes is Noble rot, also known as Botrytis cinerea. This specific fungal infection is beneficial under the right conditions, particularly in humid climates where fog can form in the morning. When grapes like Semillon and Sauvignon Blanc are infected by Botrytis cinerea, the fungus punctures the grape skins, allowing water to evaporate. This concentration of sugars and flavors in the grapes results in a rich and complex wine with distinctive honeyed and fruity characteristics.

Noble rot enhances the sweetness and depth of flavor in the wine, which is essential for the style of Sauternes. The process produces wines that are unique due to their complexity and balance of sweetness with acidity, making it a hallmark of high-quality sweet wine production. Other fermentation processes, while important in winemaking, do not contribute to the specific characteristics associated with Sauternes or similar sweet wines.