Kettle Sour Reaction

[Morrey]

I have made dozens of kettle sours but all have been in the boil kettle, not in a fermenter. Due to wild temp fluctuations we are seeing, I decided to sour in a fermenter bucket with a blowoff and controlled by an atc at 87F

L Plantarum starter all fine, cooled 1.040 wort to 90F, pitched starter and sealed lid. 48 hours later I took off lid to take a ph reading, all looked normal except I see the starsan in the blowoff bucket was foaming. I don't think lacto off gasses so I was afraid I may have gotten sacch contamination, but I did sanitize extremely carefully to prevent this. When I stirred before taking a reading, the wort foamed up and almost spilled over the lip of the fermenter bucket before settling down quickly.

I took a hydrometer reading and it was dead on 1.040 just where I left it two days before...no attenuation thank goodness. The wort has a fresh lemonade smell and a bright sour/sweet taste. All normal for sure. But I have never soured under a sealed lid and this foaming and blowoff tube activity surprised me. Has anyone seen this????

 

[ryanmbeal]

Some slight airlock activity typically happens. In my case it could just be off gassing of CO2 I purged the wort with or I've seen some of my wort with L. Plantarum from Swansons test positive for wild yeast. I'm not able to be sure if the Swansons pills were the source of wild yeast though.

I get fully soured in a day or two and then pitch 1056/001 ASAP and typically only see the gravity drop 1.002-1.004 before pitching the yeast. If it is wild yeast in there it doesn't get a chance to out compete the Lacto or Sacc.

 

[ryanmbeal]

And as for the foaming...I can't say I've seen that.

 

[Morrey]

And as for the foaming...I can't say I've seen that.

This was my first kettle sour in a closed system. Apparently there is some type of reaction going on during the souring process that made foaming happen. I never saw this in a boil kettle (my normal method) so this seemed different to me.