Looks like you should enjoy your beer before you assault people:
Beer bottles are often used in physical disputes. If the bottles break, they may give rise to sharp trauma. However, if the bottles remain intact, they may cause blunt injuries. In order to investigate whether full or empty standard half-litre beer bottles are sturdier and if the necessary breaking energy surpasses the minimum fracture-threshold of the human skull, we tested the fracture properties of such beer bottles in a drop-tower.
Full bottles broke at 30 J impact energy, empty bottles at 40 J. These breaking energies surpass the minimum fracture-threshold of the human neurocranium. Beer bottles may therefore fracture the human skull and therefore serve as dangerous instruments in a physical dispute.
Source: “Are full or empty beer bottles sturdier and does their fracture-threshold suffice to break the human skull?” from Journal of Forensic and Legal Medicine, Volume 16, Issue 3, April 2009, Pages 138-142