You could--but without any theory of microorganisms, why would you? If anything, the water tastes slightly worse after boiling and sitting, but the beer tastes

You could--but without any theory of microorganisms, why would you? If anything, the water tastes slightly worse after boiling and sitting, but the beer tastes good! More seriously, I bet alcohol and hops do play a role. The alcohol isn't enough to sterilize anything (which requires a much stronger concentration: ~70%, usually). However, it and the hops could help maintain sterility once the heat has done its job. Bacteriostatic water is used to dilute drugs for injection, and it uses a similar principle: a small (0.9%) amount of alcohol is added to keep any bacteria from getting a foothold.