^so yes, not quite at the stage to be home brewing a sour....but I would like to get there someday.
As I do love a good sour
brewing sour beer isn't
that much harder than a clean beer.
But as far as home brewing sours, I think the main ingredient is time and allowing your brew be exposed to the air.
time yes, air no. you don't need to worry about exposure to O2, even with your best efforts enough air will get in there. too much air can result in acetic acid (AKA vinegar) and that's not the kind of acidity & flavor you want in your beer. i do primary fermentation in a large carboy (or bucket), then transfer to a secondary that i fill all the way to the top (to the narrow part of the neck). there is less than a inch between the surface of the beer and the stopper/air lock.
time & space are typically the toughest obstacles. most sours will take at least a year of aging. you need somewhere to store that carboy for many months, preferably somewhere dark and that doesn't get too hot, which can be a challenge for apartment dwellers.
trick to brewing sour beer is to get a pipeline going. first year is rough while you sit around and watch the beer age, but once that first batch comes online you're rolling (as long as you re-brew right away to refill the pipeline).
Have you tried using some of the fancy $18 a bottle sours and adding them to your own sours
yup, i prefer using bugs from bottles to most commercial offerings (certainly better than anything offered by Wyest or White Labs, smaller yeast vendors tend to have much better bugs). at bottle share parties, i've been known to show up with a sanitized jar with some weak wort. folks know to save the last pour for me. dregs go in the jar, give the bugs a few weeks to ferment out the wort and recharge their batteries, and boom. i currently have 2 cultures going, both based on dregs from several commercial beers.
here's a list of commercial beers with viable dregs. not exhaustive, but a decent start.
As my understanding is frequently sours are a blend of longer aged batches and younger ones
Mostly to keep the cost down
not all sours are blends. certain styles need to be blended by definition, such as most belgian styles (gueuze, kriek, etc.). many north american sours are single-batch beers.
i've never heard of blending being done for cost reasons. as far as i know, blending is done for:
1) taste - the older beer will be more sour, the younger beer will be maltier, sweeter, etc. blending is done to get the right balance of the two.
2) carbonation: the residual sugars in the young beer are what carbonates the beer. instead of adding priming sugar at bottling, you're adding a beer that already has sugars in it.
