28B - Mixed Fermentation

BJCP Styles:
28B - Mixed Fermentation Sour Beer
28C - Wild Specialty Beer (oaked)
34C - Experimental Beer (base beer before souring)
23D - Lambic (bug mix from Russian River's Sonambic: Sonoma County Lambic)

Treasure trove of info from Milk the Funk

Here's the thing. There's no category specifically for "I harvested some wild yeast and wanted to make a beer with it" in the BJCP. So I'm making this a mixed fermentation with some wild yeast I harvested then hitting it with some bugs from the bottom of a bottle of a commercial American wild. Because I harvested some wild yeast and wanted to make a beer with it. 

I'm using my house saison for the base with a simple grain bill: some leftover CO Proximity base (500g), Maris Otter (the rest), 1kg of honey, and Sorachi Ace as the only hop. 

As for the primary yeast: this is a wild strain I harvested from a jug of Kirkland apple juice a few months ago. I noticed the half full container was building pressure in the fridge so I took it out, added an airlock, and let it do its thing. After a few days it slowed down, and after a couple of weeks the resulting cider had dropped clear. I took a sample (for science) and gravity reading. The gravity put it at around 7% which is what I would usually get from a batch of cider with store bought juice, my house cider yeast (Belle Saison), and nothing else. The taste was surprisingly clean. 

I saved the yeast from the container and a couple of weeks later put together a batch of cider and made a starter with the saved yeast and apple juice. It fermented up and looked to be healthy so into the cider it went. The result was a clean but slightly funky cider that dropped super clear after a few weeks in the keg. 

Knowing yeast behaves differently for cider than beer I wanted to give the "wild basement yeast" a go in a beer. And here we are. It's been almost 4 months since the cider batch so the starter was very slow to get going. It has now been 36hrs on the stir plate and is finally showing signs of activity. Tonight I hope to pitch into the wort I made last night. UPDATE: pitched after 48hrs on the stir plate at 30°C

I'm expecting funk. I'm hoping for funk. I just hope it's the pleasant wild fruity funk and not the baby diapers or vomit kind. This will be a "wait and see" project. I have a bottle of Russian River Beatification in the fridge which I will use for the sour bugs (after drinking the beer for science), and dedicated sour keg where this will sit for several months for its "mixed fermentation" phase.  

Full recipe is on BrewersFriend but here's the TL;DR:

  • 2021-3-31: brewday
  • Fermentables: Maris Otter, CO Proximity base (leftovers), Honey
  • Hop: Sorachi Ace
  • Yeast: ^see above^ We'll call it the wild basement yeast
  • OG: 13.2°P
  • 2021-4-5 (+5): kegged with oak spiral and dregs from Beatification 
  • 2021-8-6 (+128): tapped
2021-3-30 (-1): Using some starter wort I had saved in the fridge 

It's been in there a while so I gave it a quick boil

Saved wild yeast from the cider

away we go on the stir plate

2021-3-31: all Sorachi Ace hops - first wort and flameout. This has been a favorite for the house saison. 

1kg honey

Floor Manager Steve

Used up 2 bins of grain and got 500g of CO Proximity and 3.5kg of Maris Otter. Time to restock.


Mash temp

Mashing in the electric kettle. I have a 2 vessel system but it's unnecessary for lighter beers when I can easily lift the bag. Single vessel is much more efficient and faster than having to mess with all the transfers. 

Boiling the things

Brew session beer. 

Late hops ready to go and set to chill. Since the yeast was still thinking about getting going I didn't need to chill to pitch temp. I probably spent all of 5 min getting the wort down to 40°C then sent it to the fermenter where it will hang out till time to pitch the yeast.

OG looking like 13.2°P. A bit higher than expected; fine crush and 1kg of honey resulted in 80% efficiency. 

And we're ready

2021-4-1 (+1): 36hrs in and the yeast is doing things. Hoping to pitch tonight. 

2021-4-2 (+2): Yeast pitched last night after about 48hrs on the stir plate and this morning it's bubbling away in the fermenter.

2021-4-5 (+5): Transferred to keg-secondary 

2021-4-5 (+5): gravity check - still has a bit to go. looking like 1.013/3.3°P. Tasting funky but should be a good starting point for things to come. 

Russian River Beatification will provide the extra wild yeast and bacteria for a long ferment 

Oak spiral and sludge from the bottom of the Beatification bottle added

Away we go (again). Currently just a pressure gauge but I'll switch this out for a spunding valve or airlock when it starts building up with some consistency.  

2021-4-18 (+18): Things are happening in there and it's producing some pressure. Spunding valve set to just under 15psi. 

2021-5-6 (+36): 1 month sample. It's tasting not like garbage! Actually it's surprisingly good especially for only one month in. The Russian River bugs are doing their thing and it's got a little funk and a little sourness. So far so good! 

2021-5-19 (+49): Kegged up what was left of the base beer (1.5G) a while ago and finally moved it to the keezer. It had well carbonated itself and was looking like it would be a keg-o-foam, but it is possible to get a decent pour if I dump a bit of foam first. This is the base "wild saison" with no extra bugs added. Taste is saison-y with light funk and notes of lemongrass. Quite tasty! FG check came out to 2.3°P and 5.8% ABV.

2021-5-20 (+50): realized I forgot to do a pH check on the last sample so here it is. Looking very good at 3.4. Hoping it won't go much lower than that, it's already nice and tart. Tasting very good, same mild funk and noticeably more sourness than the last sample about 2 weeks ago. For comparison, the non-soured base beer came in at 3.75, which is surprisingly low and it does have a slight tartness to it, but nothing like the sour keg version. 

2021-8-4 (+126): checkup sample. This seems to be ready, or at least not producing as much pressure as it was. According to the gauge it has dropped from 12psi to just over 10. Acidity is quite tart but I did not check with the pH meter this time. I expect it hasn't changed much. Clarity: it's much more clear than last checkup. Flavor: on point; slightly funky and tart fruit. not getting much of the oak but all around it tastes really good - looking forward to having this on tap. 

2021-8-9 (+131): Tapped/chilled sample. Building some carbonation and showing a bit of foam. Big grapefruit with noticeable oak. Tasting good so far! 

2021-9-1 (+155): This came out really great and the keg did not last long. It now has a new batch (#2) of fresh beer in there on the same bugs. Hopefully that will come out as tasty as the first batch. I did save some cans and a big one for blending later.