Perennial Artisan Ales - fancy Belgians and experimental beers
4 Hands - hoppy ales
Civil Life - EXCELLENT session beers
Urban Chestnut - they have two 'series', the traditional ones and the experimental ones. The traditional ones are mighty fine German lagers.
Schlafly - two locations, one on Locust (Tap Room) and the other in Maplewood (Bottleworks). The Tap Room has one off beers, really good food (get the special, whatever it is), a small patio, no tour, and is in a historic building. I love that place. The Bottleworks is the production facility with tours, a huge patio, great food, and a place to purchase any swag you want. I also enjoy that place.
I would stay out of Square One. I was there a year ago and had the most painful experience of trying to drink totally flawed beer in front of the owner who was going on and on about his fantastic brewmaster. Ugh. I have never had more acetaldehyde laden beer in my life! Or astringent beer... or tart Scottish beers... it brings me nightmares.
Buying beers: Wine and Cheese Place in Clayton