A very old saying that means to tell someone the full truth, frankly and unambiguously. This is derived from the fact that in the Middle Ages it was common practice to adulterate wine on a large scale. An innkeeper who poured "pure wine" was an honest man who did not cheat his guests. From the 16th century comes the version "pouring louder wine", and from the 18th century onwards the present form prevailed. There are numerous local expressions, for example in Swabian "pure Wei eischenke". Very often the expression is found in political rhetoric. On this topic, see also the section on wine growing customs, in vino veritas, drinking culture, toasts, wine enjoyment, quotations and drinking.