the style of wine intended. Manipulation of the grape before pressing increases the amount of lees and complicates pressing. For the development of a quality wine, their use is excluded or very limited. The settling The settling is intended to clarify the wort by removing the lees from it. The lees are colloids in suspension, debris from the skins or pulp, and exogenous debris (soil). Static settling consists of leaving the must to let the debris settle: after pressing, the must is left to stand in a tank away from air. Suspended particles precipitate to the bottom of the tank. This is facilitated by the addition of pectolytic enzymes which are long chain carbons composed of pectic compounds. These pectins give a high viscosity to the juice, cut the suspended particles into shorter chains, and accelerate precipitation. Refrigeration of the wort is needed: if the fermentation starts, the release of bubbles of carbon dioxide would spread suspended particles throughout the wort preventing their deposition. After the wort is clarified it is decanted for fermenting. Dynamic settling is performed with a machine that accelerates the separation of the wort from the lees. The centrifuge removes the largest particles but does not achieve a high level of clarity. Settling by flotation is a technique where the introduction of a gas at the bottom of the tank creates bubbles which cause the particles to rise to the surface where they are removed by a scraper. Filtration with a rotary vacuum filter is relatively slow but effective. It is often used to recover clear wort in the lees exiting the centrifuge. In addition enzyme treatment can improve the settling of the Finings. Bentonite plays a mechanical role of ballast to settle the colloids – it accelerates the sedimentation rate. Gelatin is also used to flocculate the suspended tannins extracted by the press. Often associated with a bitter taste, their removal is generally beneficial for white wine. Polyvinylpolypyrrolidone or "PVPP" allows the fixing of polyphenols and eliminating them. These molecules are responsible for the browning of wine and their removal gives an element of stability in the future drink. In the "stabilisation of lees" (liquid cold stabilization) the winemaker regularly adds lees in suspension for several days so they do not settle immediately. Then he proceeds to a conventional settling as indicated above. This technique allows the enrichment of the wort with precursors of "thiol"