A catch-all for beers fermented with wild yeast or bacteria that don’t fit the defined sour and wild categories. Character ranges from funky and earthy to tart, depending on the microbes and base beer; the unifying trait is wild fermentation outside an established style.
Origin
Before isolated yeast cultures, all beer was fermented by whatever microbes happened to be present. That older, wilder approach never fully disappeared, and modern brewers have embraced it anew, courting wild yeast and bacteria for complexity. This category holds the experimental wild and spontaneously fermented beers that fall outside the established sour traditions.
Notes
The bucket for adventurous wild and farmhouse-leaning beers that aren’t a lambic, gueuze, Flanders red/brown, Berliner weisse, gose, or a defined Brett or sour ale — the experimental edge of the sour world.
Defining examples
(varies — wild/spontaneously fermented beers outside defined sour styles)