What is an effect of prolonged lees contact in white wine?

Prolonged lees contact in white wine significantly contributes to the development of bready flavors, which are often associated with autolysis. During this process, the dead yeast cells, known as lees, break down and release compounds such as amino acids and polysaccharides into the wine. These compounds can impart rich, toasty, and bready flavors reminiscent of fresh bread or brioche. This technique is commonly used in wines such as Champagne and certain styles of white Burgundy to enhance complexity and mouthfeel, creating a creamier texture and adding layers to the flavor profile.

In contrast, increased fruitiness typically results from other factors, such as the grape variety and fermentation methods. Increased acidity in wine is more closely associated with the choice of grape and the climate where it's grown, rather than lees contact. Lastly, the reduction of tannins is not relevant in white wines since they generally contain lower levels of tannins compared to red wines, and prolonged lees contact does not significantly alter that aspect. Thus, the improvement of bready flavors stands out as the key effect of prolonged lees contact in white wine.