Dark Sour with Hilgardii

This was an experiment to see what Lactobacillus Hilgardii could do with IBUs. I had previously used it for a quick sour, but that was with no IBUs. I’ve heard tale of strains being able to handle upwards of 30 IBUs, but above 15 I would say the limit before there is a big drop off in lactic acid production (full list of Lactobacillus and their IBU range).

This 1 gallon batch was pulled off from the cookie stout (aka Adjective Stout 2017) after the wort was cooled to 100F. It was in the 90sF in my garage at the time, so I just left it to sour in the heat. I had previously kept it around that temp the first time I used it to sour with, so I figured it would be hot enough, though ideally it would be better to keep it a little closer to 100F. With cultured strains (this being from White Labs), I did not get the pH to 4.5 first (which helps limit bad bacteria from getting in), rather just purged the head space with CO2 (which also helps limit bad bacteria from getting in).

I will say though that it’s a good idea to pre-acidy the wort with lactic acid as it can help with head retention as sour beers tend to lack in that department. From the Milk the Funk site: “Proteolytic activity has been shown to decrease as pH falls below 5.0 for some species of Lactobacillus. In order to combat poor head retention in beers that are soured with Lactobacillus, it has been suggested by German brewing scientist, Burghard Hagen Meyer, to lower the pH of the wort to 4.5-4.8 with food grade lactic acid or phosphoric acid before pitching Lactobacillus.”

Good luck to me.

Recipe:

Batch Size: 1 Gallon
OG: 1.064
SRM: 34
Est ABV: 6%
IBU: 34
Boil Time: 90 Min

Malt:
(65.8%) – Maris Otter
(15.8%) – Flaked Oats
(6.7%) – Acid Malt
(5%) – Crystal 120
(3.8%) – Chocolate Malt (added after conversion)
(2.9%) – Carafa III (added after conversion)

Mash:
155F for 70 Minutes

Hops:
Boil
.20 oz (35 IBUs) Magnum (14% AA) @ 60 Min

Yeast/Bacteria:
WLP678 Lactobacillus Hilgardii
WLP002

Here’s what went down:

Brewed 10/7/17

Cooled the wort to 100% and pitched some WLP678 Lactobacillus Hilgardii slurry. Kept in my garage which was about high-80s to low-90s.

10/11/17: The pH at 4. Considering the IBUs are in the 30s, I expected not much more of a drop. That’s also probably what the beer finished at and the lactobacillus did nothing. Pitched the WLP002 (didn’t transfer it to a secondary).

11/12/17 Tasting notes and video:

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