Well, the first time I took liquor I was only 16. Then again, you ARE making an assumption about the kind of people they are. My first two host fathers were pretty big drinkers, and one of my host moms as well, so it went over pretty well. I had another host family who didn't really drink, but saw it as a form of celebration, like if I had brought a bottle of champagne.
There's always a chance of a gift being inappropriate. I doubt they would voice any kind of displeasure over receiving a gift, however, based on the fact that A) you're a foreigner, B) you haven't met these people, and C) you thought enough to bring something. If you feel a little uncomfortable with it, feel free to bring additional gifts. On any given trip, I've taken no less than 6 or 7 things for a 4 person family. Exotic coffee, sweets, liquor, even articles of clothing.