We spent this afternoon on the 'Big Sippin in SOMA' tour, and couldn't recommend it more. It was only myself and my fiance on the tour, with our guide Lena, and we visited 3 different breweries (Thirsty Bear, Black Hammer Brewing and 21st Ammendment).
We couldn't recommend this tour enough. We never would have seen these parts of the city without doing this tour, nor would we have found these amazing bars!
You get LOTS of beer to taste, great selection and our guide provided great guidance as to what would be interesting to try and what we would like (based on what we usually like to bev on!).
Lena was really friendly, so knowledgeable but also a great laugh. We were told a couple of days before the tour we were the only ones booked on, and offered another couple of options (which we couldn't do) but I thought this was really great in terms of customer service.
When we're back in San Fran, we absolutely plan on booking onto another tour with these guys!