I know you didn't ask about food tours but in my recent research for our Prague trip, I came across this website for what I hate to call a "food walking tour" as it seems much more than that.
http://www.tasteofprague.com
Looks like they include some aspects of Czech beer in their tours which might be of interest to you. They were fully booked for our dates, but the various email correspondence I've had with them has been timely and informative.
I ended up buying their Prague Foodie Map and Guide online and it has been useful to us during our trip (...we're in Prague now).
Peter