I store my yeast slurry in the fridge until next brew day. If it’s more than a week, I’ll feed it a day or so before brew day. On brew day I remove it and allow it to slowly warm up to ferment temp while my wort is chilling. I always pitch when they are the exact same temp. Is this necessary? I worry about shocking the yeast. How tolerant is yeast to temperature change?
I routinely pull my yeast starters out of a 40-degree fridge, decant and pitch the slurry into 70-degree wort. Never had a problem doing this. Lag times between 4 and 6 hours are normal and terminal gravity is usually reached within 3 to 5 days of pitching, so no evidence of any negative effect.
I have always gone on a 20° rule of thumb. Never had any issues.
No, it is not necessary. Temp shock in pitching temps is an unfounded myth. In addition, the yeast starts using up stored nutrients 2hen it warms, and it’s better to do that in your wort. My experience of years and hundreds of batches is that there’s no downside to just taking it from the fridge and pitching.
Cool. One more myth busted, one less thing to worry about.
Ive read a few times that cold yeast into warmer wort is more forgiving than warm to cold. I get the slurry out of the fridge and let it warm a little before pitching, but it is still cooler than the wort (for lagers it is pretty close to same temp).
Me also!
I usually get the slurry out of the fridge when the boil starts.