Physico-chemical separation process for fine-grained solids. Originally, it was mainly used in ore extraction to separate ore from the deaf, non-ore-bearing rock. The deaf (more difficult to wet, lighter) rocks or components are separated from the heavier ore-containing ones. The deaf and lighter rock rises to the surface and is skimmed off. Flotation agents are added to optimize the process. In the manufacture of beer has been used for a long time to clarify the beverage from the wort (concentrate from water, malt and hops).
This flotation technique has now also been used at winemaking for the degumming, that is, the grape must is exempt from suspended particles (grape skins and stems, etc.). The must is under pressure nitrogen or added air. When the pressure is released, tiny bubbles form, on which the turbid particles adhere and float to the surface and can be removed. A distinction is made between continuous flotation (permanent skimming of the foam from the surface) and discontinuous flotation (draining the clear must from the bottom in short time intervals up to a maximum of two hours). Purpose-like techniques in viticulture are filtration and Centrifuge,
Complete lists of the numerous vinification measures or cellar techniques, as well as the various types of wine, sparkling wine and distillate regulated by wine law are under the keyword winemaking contain. There is extensive wine law information under the keyword wine law,