This is only half of a sentence in English. Except for the wine, what? "Except for the wine, the dinner was awful." "Except for the wine, the carpets would still be white." "The party was great. Except for the wine." This would also work. Otherwise, I'm just left wondering if this is an idiom that doesn't translate, or a sentence that is unfinished.
"ach amhain" = "except". The "but" in your translation is extraneous. (Edit: At least, I'm assuming that DL is right and you wouldn't use "ach amhain" to try to say both "but" and "except" at the same time. I'm also assuming your interpretation was something like this: "There were plenty of drinks at the party, but except for the wine, they were all non-alcoholic.")