i've read about acetic, but lactic is new to me. anyone have links to the science? the compounds produced during fermentation should be pretty well known. i'd really like to know.
in my experience, you get funky and or fruity from brett, sourness (not to be confused with fruitiness) comes from lacto/pedio. i've had plenty of old brett beers with zero sourness.
Ive had a few beers from the guy who wrote the brett masters proj (crooked stave brewing) there can be a slight tartness from brett, but nothing intense. Ive noticed it in all brett beers more than sach/brett blends. No insight on what causes this though.