At least one bakery in my neighbourhood offers classes. The same goes for some pottery stores. In both cases these sessions are for ordinary people, not other professionals. I have a few breweries near me, but I have never heard of them offering classes/demonstrations/workshops for the general public. I know that beer takes weeks to be ready, but surely something could be worked out. The same goes for pottery, after all. I'm sure that beginning and seasoned homebrewers would like opportunities to learn from pros. Has anyone heard of breweries doing this? Has anyone taken part? If so, how was the experience?
In a brewery there are serious liability issues. Safety is a real concern and at least in Massachusetts breweries cannot be in production with visitors in the brewing space for that reason. That said, the Woodstock Inn and Brewery has "brewers weekend" packages. http://www.beeradvocate.com/beer/profile/1251/?view=ratings&ba=woosterbill I did it once and it is absolutely the full immersive experience. You can participate as little or as much as you want, ask any questions, and, oh yes, all the beer you can drink. There may be limitations now but when I did it a few years back, I was never in want of a beer.
Outside the already mentioned liability issues that come with opening your production facility up to the public, and then inviting them to use chemicals and be around massive vessels of boiling water, and other things that can injure them. Unless you're one of those lucky sorts with super cheap rent, or have a huge facility with room to spare. Or both. Space is a very precious commodity inside a brewery. Hopnado beat me to the punch with Saugatuck brewing. If I recall right they have a single barrel brewhouse inside the taproom.
Check out the AHA big brew coming soon. http://www.homebrewersassociation.org/aha-events/national-homebrew-day/
Drop In Brewery in Vermont is a prominent one. I took a beer sensory course there which was informative and some very high profile professional brewers attended. The brewmaster Steve Parkes lead the session and he really knows his stuff.
This is what I came to say. I was there in June and the brew on premise area is right off to the side of the pub area so there were a bunch of people working on stuff, the entire place smelled of brewing, and they looked to be having a good time. On one hand it is good that it is out in the open, probably hooks more people. But it was busy that day and it seemed to kind of be in the way of actual pub business.
Most homebrew shops offer classes. It's a great introduction to brewing and it's on a small enough scale that you can replicate the process if you decide to start homebrewing. Moreover the people who are running the workshops are used to dealing with folks who don't know a ton about brewing so they're able to distill the info down in a way you'll understand and are good about answering questions.