no-one really asks, though sometimes there's a quizzical look. a question like "why don't you drink?" is really quite an intrusive one, and i consider it a bit too personal for a business-client situation.
but if it ever came up, i'd shrug and say "i just don't like it".
does anybody ask you why you're not ordering squash, or shrimp, or coffee? is it any of their business?
just shrug and move on. since you say you're a chatterbox, you're capable of moving right along. if anyone insists past that, they're simply rude.