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) violated by weak interactions. Therefore, such flavour quantum numbers are not of great use. A separate quantum number for each generation is more useful: electronic lepton number (+1 for electrons and electron neutrinos), muonic lepton number (+1 for muons and muon neutrinos), and tauonic lepton number (+1 for tau leptons and tau neutrinos). However, even these numbers are not absolutely conserved, as neutrinos of different generations can mix; that is, a neutrino of one flavour can transform into another flavour. The strength of such mixings is specified by a matrix called the Pontecorvo–Maki–Nakagawa–Sakata matrix (PMNS matrix). All quarks carry a