There's essentially no hops in the beer. They literally include just enough to be legally called beer. Hops were first added in the Middle Ages in Germany, so, you're right, there would be no hops in the recipe. It's not at all a bitter beer, pretty much for that reason. They use the myrrh and gentian root for whatever bitterness there is.
But I posted the ingredients above. No frankincense, but definitely myrrh.