Kettle Sour Not Souring (OLY-605)

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Jun 3, 2020
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Not really wild or lambic, but this seemed to be the best place for this.

Brewing a sour IPA. Recipe is:

Batch Size: 20.8 liters (5.5 gallons)

OG: 1.067 | FG: 1.009 | ABV: 7.49% | IBU : 22.55 | SRM : 6

1.8 kg - Pale Wheat Malt (33%)
0.9 kg - Rye Malt (16.5%)
2.75 kg - Low Colour Maris Otter (50.5%)

85 g - Citra, Whirlpool for 30 min at 73 °C
28 g - Galaxy Whirlpool for 30 min at 73 °C
28 g - BRU-1 Whirlpool for 30 min at 73 °C
28 g - Citra Dry Hop (High Krausen) for 7 days
56 g - Galaxy Dry Hop (High Krausen) for 7 days
56 g - BRU-1 Dry Hop (High Krausen) for 7 days
56 g - Citra, Dry Hop for 3 days
85 g - Galaxy, Dry Hop for 3 days
85 g - BRU-1, Dry Hop for 3 days

Mash at 67

Lacto - Omega OLY-605
White Labs - Saccharomyces "Bruxellensis" Trois WLP644

After an initial 15 minute boil, I chilled to 30 C (86 F) and (I thought) dropped the ph to 4.5 using 20 ml lactic acid.

Pitched Lacto OLY-605 at 1900on Saturday (11th June 2022), into 25 litres wort. Held wort at 30c (86 F) with a heat pad thermostat. This morning Sunday 12th I went to test the ph at 0800 (didn't think it would be done, but thought it would be best to check on it after 12 hours). The ph had risen to 4.73. I assumed it was just a measuring error so left it.

At 1200 I tested the ph again, it was now reading 4.9! Worried about bugs, I added another 10ml lactic acid to bring the ph down to 4.35.

What's going on? I'm assuming the ph hasn't really risen (not a chemist but that doesn't seem possible). More likely that it wasn't mixed properly. However, I would have expected to see some souring by now, wouldn't I?

There are two things that I think could be going wrong: the temperature of the wort or the health of the lacto. I didn't make a starter, just used the sachet of the lacto. The manufacturing date was April, so two months old - I don't think that's too long? However, it says it's good for 19 liters (5 gallons). My wort is more like 25 liters (6.6 gallons). Is that likely to be a problem? The packet says the wort should be 20-35C (68-95F), so I went for 30C (86F). Omega yeast says repeatedly that it doesn't need to be that hot, much less so than most lacto. Just put in a warm place. I held it at 30c nonetheless. Could that be a problem? Should it be hotter or colder?

Am I just worrying/being impatient? It's only 16 hours, is that too soon to be expecting to sour? Omega says peak souring by 24-36 hours, so I would expect some by now. I also see lots of people who say this lacto has worked in 16 to 18 hours and is quick. Maybe because I didn't use a starter there is more lag for it to wake up?

What do you think? It's my first kettle sour so really not sure what to do. Just wait? Change the temp? Something else?
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I have had no issues with this strain at 20c or 30c. Sounds to me like your cell count wasn't high enough as you did not make a starter. I am still using the same batch i bought 3 years ago and when i make a starter it can take more than 48 hours to finish but i have no problem post souring as long as no hops are present.
There are no hops in the wort, right?

What pH meter do you have? When and how did you calibrate it? There's clearly a measurement error because there's no reason for the pH to rise.