You're trying to set up very specific conditions on the surface of a Reblochon to provide a good environment for
B. linens. First, you are increasing pH (decreasing acidity). This is the reason for the initial phase waiting for Geo to take hold. Second, you are trying to provide an environment that discourages other beasties from competing with
B.l.
It seems to me that using a yeasty beer wash will work against both conditions you're trying to set up. I don't remember what pH beer typically measures, but it is acidic. Maybe a good pH, maybe not. Also, you'd be adding other critters that may or may not compete with
B.l.
I think adding the beer to the wash would be a fun experiment though. What do you think about doing this batch per the recipe, and trying the beer on your next make? That way you'll have a good benchmark for what the cheese is supposed to be without throwing in unknowns. Or just go for it.
Larry