Between checking a box and padding, you're looking at an almost unreasonable amount of space required, and considering how insane some airlines can seem to be with their checked baggage fees, I'd recommend an alternative:
Go to your local store that carries clothes of any kind, the cheaper the better, buy the cheapest socks you can buy that are big enough to fit a bottle in them, and have a decent amount of padding and use those. Slip a bottle in each sock, put them into your check bag, and you're golden. This keeps them from clanging around, setting off airport security alarms, and overall makes things a lot easier and simpler.
Just make sure the check bag doesn't exceed the weight limits. I'd imagine a full case worth of beer bottles can push the limit, so make sure you weigh the bag with the socked beer bottles in it, verifying that it doesn't exceed the carrier's limit before going to the airport.