A settling period of about 24 hours is usually sufficient to clarify a juice. Although settling is normally done at cold temperatures, it should be noted that cold juices actually settle more slowly than warm juices. Large wineries often clarify juices with a centrifuge or by filtration with diatomaceous earth. Manipulation of solids content in juices can be an important stylistic tool. Depending on the grape variety and wine style, fermentation of whites can take place in inert vessels, in oak barrels, or in a combination of the two.
Much effort is put into the search for the perfect yeast strain for a given white wine.
With most white wine fermentations temperature control is imperative, although barrel fermentations tend to be self-limiting in this regard. Chaptalization is practiced with whites, but not as frequently as with reds. Many white wines are left with some residual sugar, and the most common way to do this is by stopping the fermentation. This can be done by rapid chilling, or by physically removing the yeast from the wine by filtration or centrifugation. In both cases a follow-up addition of SO 2 is necessary.