Stuck kettle sour

[fnffishcore]

Ok, long story short-ish: I started a kettle sour a week ago. Pre-acidified to 4.2 pH (overshot a bit, target was 4.3). Pitched a year old pack of Omega Lacto at 90F, planned to let it roll over the weekend while I was away then finish the boil Monday. Well, pH only dropped to 3.8. I let it roll another day and set the temp controller to 80F. No dice. So I grabbed some Goodbelly shots and pitched 3 instead of the usual 2 - they had been expired for a couple days so I was afraid the culture count would be lower - and cranked the temp control back up to 95F, but no luck after a day. Fast forward to this morning, I gave it what I deemed one final check and the pH has actually gone UP to 3.9?!

Before I pull the plug and rebrand this batch to an ever-so-mildly tart instead of a sour, anybody have any suggestions? I know I left out some details (grain bill being the big one) but I’m on my phone and don’t have that readily available. Thanks!

 

[VikeMan]

Did you calibrate your pH meter?

 

[fnffishcore]

Did you calibrate your pH meter?

Yup, it's calibrated.

 

[VikeMan]

Fresh calibration solutions? And have you ever tested your meter for drift? I doubt that the pH is actually increasing.

Before I pull the plug and rebrand this batch to an ever-so-mildly tart instead of a sour, anybody have any suggestions?

This is sort of the way I would describe most of my soured worts before the fermentation with yeast. Or at least I'd call them "mildly tart" without the "ever so" prefix. The sugars in unfermented wort can really cover a lot of sourness.

If this is not your first kettle sour, and this is not as tart as you are used to at this point, then I would suggest patience. If the Goodbelly was kept refrigerated, it ought to get the job done with time, even though it was past its best by date.