Sesquiterpene synthase involved in the biosynthesis of volatile compounds that contribute to the characteristic flavors of black pepper (PubMed:29248443). Mediates the conversion of (2E,6E)-farnesyl diphosphate (FPP) into beta-caryophyllene and, as a minor compound, into alpha-humulene (PubMed:29248443). (2E,6E)-farnesyl diphosphate = (-)-(E)-beta-caryophyllene + diphosphate (2E,6E)-farnesyl diphosphate = alpha-humulene + diphosphate Binds 3 Mg(2+) or Mn(2+) ions per subunit. kcat is 0.455 sec(-1) with (2E,6E)-farnesyl diphosphate as substrate. Secondary metabolite biosynthesis; terpenoid biosynthesis. Mostly expressed in stems and, to a lower extent, in leaves, roots and fruits. The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family. Tpsa subfamily.