I think it's like SonomaProducts.com said, the alcohol probably disolved the
shellac and rehardened against the bottle.
I would try using some thin nylon twine wrapped around two pencils and
sliding it back and forth to cause it to 'saw' it's way through the shellac
as close to the bottle as possible. If you don't have nylon twine, try
using unwaxed dental floss (don't bother with the waxed stuff), or some
other strong thread (like the kind of thread you would stitch jeans with or
a jacket). It will probably break often and require a lot of paticence, but
it should allow you to break the seal close to the bottle.
Try not to use force to remove the bottle because the wood will probably
give before the bond between the bottle and the wood does (that is, you'll
remove a chunk of wood from the shelf).