I have several times traveled Europe - US with 12-24 bottles of wine and up to 5 liters of other liquor in checked or carry on (pre war-on-water) bags. My experience and advise is to declare it on your customs form in writing, and be prepared for a hassle but don't expect one. Half the time the Immigrations/Customs folks won't even notice what you have written down on the form as long as you don't look like you are trying to commercially import beer. (i.e., don't waltz through customs pushing a dolly with 10 cases labeled "beer" stacked on it.) If you haven't brought back enough stuff to exceed the duty free limit, they may not even flip the form over to where the alcohol would be listed. The form is set up such that there's no check box for alcohol, and alcohol is not "food" to my understanding. ( http://www.cbp.gov/xp/cgov/travel/va...ation_form.xml )

The penalty for not declaring the items on the customs form is pretty nasty and not worth the risk.

The duty calculation is based on volume of alcohol not the purchase price, so it takes a lot of beer to have a lot of alcohol, and the duty rate isn't that high to begin with. You're looking at a couple of bucks per liter of beer. So they have very little motivation to collect the duty unless they decide they don't like you or are otherwise on a power trip.

I have no experience with state laws interfering with this process. Most of my arrivals with alcohol have been at IAD and ORD.