Chaptalization or the addition of sugar is regularly practiced where permitted by law. Finally, a special nitrogen-based yeast can hasten fermentation. Fermentation generates tremendous heat, but this is controlled by cooling fermentation vats. Whites, which depend more on primary fruit aromas are almost invariably fermented cooler than most reds. Next, the winemaker decides when to rack and clarify.
Red wine looks like rusty mud once it's out of the destemer.
Fermentation brings the must a step further to clarification, but there is still much to do. During the first and sometimes second fermentation, lees or sediments fall to the bottom of the tanks. The wine is then moved to another barrel, lest the sediments affect its flavor. This process is often repeated within six months to three years. Eventually, you get a clear wine.