We stopped at Brauhaus Mayen for the 4th time last weekend. I was a bit surprised their Saturday opening time was 1400 (no lunch) but that was okay. We walked around town a bit, did some shopping, then headed to the brauerei for bier and a small lunch.
One caution, and this was my fault for not verifying, is do NOT order "pils" or "helles" or you'l end up with Warsteiner swill. I did order a helles thinking, naturally, I'd get their local homemade helles. Wrong, the swill of Warsteiner came out. I got that corrected ASAP and had a couple of their local helles biers. It's wonderful stuff.
This time we just had vorpseisen (appetizers) for lunch. I went with bratkartoffelen while my wife had kartoffel creme suppe (cream potato soup). Both were very good. We've dined here three times in the past with the normal schnitzel menu. All were good. I've never found a brauerei I didn't like. Without a doubt, when we're in Mayen/Monreal area, we're stopping at Brauhaus Mayen for bier!