Maceration is the winemaking process where the phenolic materials of the grape—tannins, coloring agents (anthocyanins) and flavor compounds—are leached from the grape skins, seeds and stems into the must. To macerate is to soften by soaking, and maceration is the process by which the red wine receives its red color, since 99% of all grape juice (with the exceptions of teinturiers) is clear-grayish in color. In the production of white wines, maceration is either actively avoided or allowed in very limited manner in the form of a short amount of skin contact with the juice prior to pressing. This is more common in the production of varietals with less natural flavor and body structure like Sauvignon blanc and Sémillon. For Rosé, red wines grapes are allowed some maceration between the skins and must, but not to the extent of red wine production.