Ok so I do most of the import & export for my particular division of my company (um in the top 50 of fortune 500 this year) and am similarly perplexed as to how US customs interacts with our northern border. Somehow my chemical shipments act just like domestic shipments. God forbid you need to ship to MX or ER, however, then you are in for some real customs scrutiny. Sorry....RANT induced by no one covering my work during vacation absences! : )
Good luck with homebrewed hooch though, seriously!