Holy shit that's a good idea for a GMO. If you wanted to go GMO free you could possibly breed weed to get some of the right flavors and use it instead of hops.
See, the alcohol in your blood protects you from the energies from time travel so your blood doesn't boil. The drunker you are the more well protected you are for longer jumps in time. He had to drink that much to safely come back and warn us.