Subscriber Exclusive

Mixing It Up: Complex Fermentations, Made Simpler

Opening your fermentations to a wider array of yeasts and bacteria can add great complexity to your beers. It can also add complexity to your brewing process—but the challenge is both surmountable and rewarding.

Josh Weikert Jun 6, 2022 - 15 min read

 Mixing It Up: Complex Fermentations, Made Simpler Primary Image

Photo: Matt Graves/

I remember my first mixed-culture fermentation: I was so nervous about infecting my home brewery that I pitched a Lactobacillus culture into my Berliner weisse wort in the open-air environs of my deck, far from my preciously not-bacteria-laden equipment and fermentors.

The resulting beer (my Scared Sour Berliner Weisse) was successful, and I avoided creating a runaway Lacto infection in my brewhouse. That turned out to be an unjustified fear on my part. The biggest lesson I learned is that mixed cultures are nothing to be scared of, while they can be an outstanding way to expand your repertoire of flavor compounds, combinations, and profiles as a brewer.

A few quick hits before we go any further:

  • First, don’t assume that when we say “mixed culture” we’re always talking about sour beer. That’s not necessarily the case—though the spectrum can vary from just a pleasant kiss of funk to bracing sourness, via gentle tartness.
  • Second, a mixed-culture fermentation is not the same as spontaneous fermentation, where native cultures in the air or wood go to work on the beer. Creating a true “wild ale” entails considerations and risks that we won’t get into here. (For more on that, see Spontaneity: Prospecting for Bugs.)
  • Last, and most important, is this: Don’t expect the bugs to do your work for you.

Make & Drink Better Beer

Subscribe today to access all of the premium brewing content available (including this article). With thousands of reviews, our subscribers call it "the perfect beer magazine" and "worth every penny." Your subscription is protected by a 100% money back guarantee.