For white wines a winemaker must decide whether he is going to make it protected as much as possible from oxygen, preserving every ounce of fresh fright flavor (preventing oxidation and stunning yeasts right at the start with added sulphur dioxide, complete destemming, low temperatures throughout, and so on) or to adopt deliberately oxidative techniques, exposing the grapes to oxygen and aiming for secondary, more complex flavours from the fruit rather than the pure, unadorned hit of primary aromas. Riesling, Sauvigonon Blanc, and other aromatic grape varieties tend to be vinified protectively while most tpo-quality white burgundy is made oxidatively. Oxidative handling may include a period of deliberate “skin contact”, not as exciting as it sounds but a few hours either in the press before it is turned on or in a special holding tank during which further flavor will be leeched in to the must from the skins. If the skins are allowed contact with juice for white wine for too long, however, they impart far too much astringence which is why grapes for white wine, unlike red wine grapes whose skins are needed for colour and tannin, are pressed before fermentation.