> Hops are used extensively in brewing for their antibacterial effect that favors the activity of brewer's yeast over less desirable microorganisms
https://en.wikipedia.org/wiki/Hops
> Hops have a long history of use as a natural preservative in beer. A little known benefit, however, is that hops also contain high concentrations of unique “alpha” and “beta” acids that can inhibit the growth of Gram-positive bacteria at surprisingly low concentrations. To that end, Hopsteiner produces a variety of natural and modified food grade hop products which can very effectively and economically inhibit bacteria growth in a wide variety of applications including food, spirits, fuel ethanol, yeast and process streams (to name just a few).
http://www.hopsteiner.com/antibacterial/
And this rule of thumb was told to me by a brewer who just got a GABF medal. The guy knows what he's talking about.
What state are you in? And have you done any brewing at scale? A lot of times you can tell that a craft beer scene is new because of how much everyone is into IPAs.