My husband, mother, and a friend went to the Brewery on Sunday. We arrived around 12, made a reservation for the 1:30 tour, and made a trip downtown for lunch prior to the tour. The tour started on time from the tasting room. Your glass is filled when the tour begins and then once more during the tour. They tour guides were very knowledgeable and did a great job giving a tour of the facilities. The tour lasted about 20-25 minutes and then you have 30 minutes in the tasting room to try all the beers they have available on tap (probably around 12 different ones) You can try as many as you want within the 30 minutes.
We had a great time on the tour, and I highly recommend visiting the brewery while in Boston.