Some bitumen suppliers in UK and other countries provide 200Kg of Bitumen in each drum, but we don't. the reason is in this case the freight costs may reduce, but the containers may damage because of the same reason (melting down the bitumen and overflow from the drum)
Bitumen can be sold in poly bags in winter only because the high temperatures would melt down the Poly Bags. Poly Bags are easy to use at sight especially for construction purposes.
Penetration Bitumen