I've arrived at the following method for pitching yeast into cold musts:
- Make a starter at room temp, 18-20 degrees C, use goferm as well. This way you're not trying to safely reduce the temp by 25 degrees in 20 mins, which I've always struggled to do without killing the yeast
- Let the starter get fully going at room temperature, which seems to take around 24-36 hours using goferm. This means that the yeast has got over the lag phase in fairly optimal conditions and shouldn't be stressed
- Take the starter out to the shed the main container is in and leave for about 12 hours, for it to arrive at the same temperature. Theory is that the massive, thriving yeast population in the starter just cools down and get a bit less active
- Pitch into main container, no cold shock whatsoever to the yeast, and they seem to take hold fairly quickly
71B seems to get stressed really easliy, I've had barrels farting out copious quantities of H2S during the early stages in the past, thankfully it seemed to blow itself out and didn't taint the cider, though I did reactively treat with Fermaid-O just to give it a hand. Worth doing a full kill with SO2 when using it, needs all the help it can get