Ouzo it is generally considered poor form to drink ouzo "dry hammer" ("ξεροσφύρι", "xerosfýri", an idiomatic expression that means "drinking alcohol without eating anything") in Greece. The presence of food, especially fats or oils, in the upper digestive system prolongs the absorption of ethanol and ameliorates alcohol intoxication. Ouzo is not used in many mainstream cocktail drinks, although in Cyprus it does form the basis of a cocktail called an Ouzini. Ouzo is a clear liquid. However, when water or ice is added, ouzo turns a milky-white colour. This is because anethole, the essential oil of anise, is completely soluble in
Flavour (particle physics) QCD). This gives rise to an effective mass for the quarks, often identified with the valence quark mass in QCD. Analysis of experiments indicate that the current quark masses of the lighter flavours of quarks are much smaller than the QCD scale, Λ, hence chiral flavour symmetry is a good approximation to QCD for the up, down and strange quarks. The success of chiral perturbation theory and the even more naive chiral models spring from this fact. The valence quark masses extracted from the quark model are much larger than the current quark mass. This indicates that QCD has spontaneous