Hi Kelly,
I second what Liam has said, and absolutely agree that the interest in beer comes first, and due to seeking out bars and off licences that stock good beer, craft or otherwise, you get to know people in the "community".
The only other take on it I might have is being a newcomer to the Irish craft beer market. I come from America originally where I joined the craft beer community organically as Liam has described. I decided to actively seek out an already-built community of beer lovers upon moving here as a way to just speed up the process if you know what I mean.
I think it's an interesting topic, especially the social aspect of how people decide which groups they would like to be a part of. When we were kids, you didn't have a choice, your friends were mates at school and I suppose it just depended on what your interests were i.e., sports, drama, music, etc. I find that now being in my mid 30's, a husband and father, and a working adult, that you have to actively find a peer group. Again, as Liam put it, the beer "community" is no different than other interest groups like train spotters or stamp collectors. We have an inherent interest in well made products that have a certain personal touch, or provenance so to speak, and I for one have focused that interest to beer due to it's social nature and it's unique combination of science and artistry.
Hope that helps,
Best of luck with the dissertation!
James