I'm not a linguist but I think this bit of jargon leaked into tech from ham radio, which is old enough that "homebrew" (in the sense of building your own radio set from components) referred to a still-earlier time when people actually did commonly brew their own beer at home. "homespun" retains a similar meaning in general usage.

Is beer part of "tech" now?

homebrew has a pretty straightforward meaning... beer you brewed at home. It's actually legally defined that way too

Maybe I've misunderstood pvg upthread but I assumed "'homebrew' has come to connote scrappy and hip" was about IT/tech because it doesn't have that connotation in the actual context of beer, at least to my knowledge.

No, you had it right - e.g. https://en.wikipedia.org/wiki/Homebrew_Computer_Club which, as you say, is probably a borrowing from older tech nerd communities.

The "homebrew computer club" made their own computers. It wasn't about being scrappy or hip, but just a cooler way of saying "homemade"

You should probably check out the denotation of 'connotation'

You should probably check out "being a pedantic douche" -- oh wait, you already did.

So it's about being cool but not about being hip? What distinction are you trying to make?