Rot gut is used in the States as well, to indicate an alcohol of poor quality.
Are there any other words you use where "rot"is used as a sort of pseudo prefix? I'm interested because we use it as a prefix often:
rotzooi, rotziekte, rotvent,rotgedoe,rotzak,rotdag.etc.
the rot-part coming from the same source:rotten --- bad quality.
Rotdag : a bad quality day. Rotgedoe: bad quality doings.
Rotwelsh: interesting ZM .