FWIW, I put a 1.072 IPA in the fermenter an hour and a half ago. As an experiment, I pitched 1 pack of BRY97 dated December 2021 at 65 F. Just checked and I had positive pressure in the airlock. Popped the lid and there were signs of fermentation. We'll see where it goes from here.
I’ve often thought we must use different metrics to determine our start times. Without a common lexicon there’s a large chance of miscommunication.
That’s a good description of your definition of start time.
I pitch Bry-97 per the mfr instructions using their pitch rate calculator. I gauge my start time as the first ‘blip’ on the Tilt bluetooth hydrometer. I see a degree increase in temp and a gravity point drop usually fairly close together. This usually occurs 16-18 hours after pitch with Bry-97. I have tons of data that support these start times with this yeast. I bought a 500g brick and used it nearly exclusively for a while. I kept track of each fermentation that showed very consistent performance.
I don’t use an airlock per se. I fill a keg with sanitizer, run a jumper from the fermenter to the keg and use the CO2 generated by fermentation to push the sanitizer into a bucket. Once the sanitizer is all in the bucket, the CO2 creates bubbles until fermentation is complete. Though I’ve never measured it, this creates a certain amount of pressure in the fermenter so this can change performance as well.
…but…. even though comparing Bry-97 to US-05 is not exactly apples to oranges, it is more like Granny Smith to Fuji. Like comparing Diamond to W34-70, they’re both apples but not exactly the same so expectations are different for each.