Best Answer - Chosen by Voting
"molim Vas, dva Karlovačka (piva)" ................ (2 beer)
but
"molim Vas, jedno Karlovačko (pivo)." .............( 1 beer)
Spiegazione:
Karlovačko is a brand of beer. Even when you just say the brand name a waiter knows you mean beer. Beer in croatian = PIVO. It changes to "pivA" in akuzativ plural...that's why the adjective/name "KarlovačkA" has to have the same ending.
You WILL however be able to hear it said in this way too (although not very grammatically correct): "Molim dvi(j)e pive" .