Head Brewer Garrett Crowell on Curating Native Yeast

We receive a lot of questions about capturing native yeast for fermentation. Since the procedures we use to capture, maintain and ferment with native yeast are fairly simple and replicable, and also because we think it’s important for brewers everywhere to continue discovering new horizons beyond the world of pure culture fermentation, we wanted to share how we go about it. Of course, who better to explain it for us than our Head Brewer Garrett Crowell, who developed the diverse blend of wild yeast and bacteria we use to ferment all our beer. Here’s Garrett in his own words on curating native yeast:

“The biggest secret to embracing your local flora is patience! Yeast and bacteria harvested from flowers, fruit, etc., tend to move at a much slower pace than lab cultured yeast. As such, knowing the flavors they produce and how they perform can take quite a while. We’re still learning what our blend of yeast can do with every batch of beer we make!

For culturing truly “wild” yeast and bacteria, I’d start with 250-500mL of unhopped wort, around 1.030. Any vessel will do. Growlers are fine, and if you have access to Erlenmeyer flasks, they tend to be easier to use. If you only want yeast, adding some hops (20+ IBUs) will help hinder bacterial growth. Part of our house culture came from some flowers that are native to our ranch. Capturing yeast from these was as simple has plucking a handful and putting them in a one gallon jug of unpitched wort. This method will vary, as we’ve repeated it with other types of flowers and berries with no success. Experiment with different oxygenation rates. For instance, while using the same “inoculation” source (flowers, fruit, ambient air), try culturing part of it with oxygen and part of it without.


Yeast capture experiment

The method for curating our house blend of yeast and bacteria involved splitting a few five gallon batches of wort into one gallon jugs. Some of the jugs were fermented with only native yeast and bacteria, and some were fermented with native yeast and bacteria mixed with lab cultured strains of Saccharomyces (Dupont and Thiriez). After fermentation, we then blended the yeast and bacteria from the various jugs based on a sensory analysis. If the beer in the jug smelled and tasted good, we’d harvest the dregs and blend it with dregs from other jugs we liked. We ended up blending an even mix of dregs from fermentations with only native yeast and bacteria and fermentations with native yeast and bacteria mixed with lab cultured strains of Saccharomyces. The final blend became the house culture we use to ferment all our beer, and it continues to evolve to this day.

To maintain the individual cultures, we mostly keep them in one gallon or five gallon carboys. Having beer on top of the yeast tends to keep it safe and healthy. From batches that are particularly good or interesting, I will keep a few vials of slurry for future use.

Best of luck with your wild yeast capturing! Always let them ferment out dry before tasting them and please share your results with us (info@jesterkingbrewery.com). For further reading, check out this blog entry from our friend Michael Tonsmeire, a.k.a. The Mad Fermentationist. Cheers!”


Jester King Head Brewer Garrett Crowell