Sam quirks a brow, giving Kaito a quick once-over. Coming from Bon Temps, his first instinct is to assume 'I can't drink that' means someone is a vampire and trying to be a mysterious jackass about it. There's a distinct lack of pallid skin and the smell of blood-rot, however. Being a bartender, Sam's second guess is -

"You not old enough?"

He's admittedly not the best judge of age at first glance, which has also admittedly gotten him into trouble a time or two. He'll have to remember to ID a little more consistently now, come to think of it. ImPorts and ages are tricky enough as it is, and the last thing he needs is to lose his liquor license.

"'Cause I could offer you a virgin version, but then you'd really just be drinkin' flavored hot water."