I too pitch cold yeast right out of the fridge into warm(er) wort with no issues. That was not my concern in my post.
Rather, the real concern is letting the yeast reach dormancy where they take much longer to "wake up" and get going in your wort. All the while, your hard earned wort is sitting there not fermenting waiting for the yeast to get started at building up their reserves prior to fermentation.
This can all be mitigated by saving slurry from actively fermented wort and put away cold into your fridge for storage. This provides the yeast with some nutrients that they slowly feed on until the next brew day. As always, repitching a slurry should be done sooner rather than later to maintain health and vitality.
That does look like an optimal procedure, brewinhard, albeit one that requires the ability to dump from the cone during active fermentation. Breweries can do this even as a cone-to-cone transfer, essentially a (potentially indefinitely repeated) adaptation of Darauflassen. As my fermenter is a 10 gallon corny, I'm restricted to harvesting yeast from a completed fermentation. If one could be assured of sanitary conditions, harvested yeast could be maintained in storage by periodically topping off the jar with fresh wort. This is an old procedure formerly recommended by, among others, Greg Noonan. That said, with a generous pitch and adequate oxygenation, normal lag times and vigorous fermentation can still be achieved with yeast stored cold for some time.
Now I'm going to have to reread Kunze, however. I believe he advises against any maintenance of activity in storage, and advises allowing yeast to go dormant and only wake up on pitching, so as not to interrupt their natural life cycle. (A recent genetic study I posted about indicates just how this is what yeast are adapted to do.) It is for this reason, among others, that rinsing yeast is advised against -- providing any cue to the yeast that it's time to ferment, without conditions permitting a complete life cycle, are disruptive and harmful. So cold pitching stored yeast may well be optimal.
One can easily achieve this by simply transferring to the serving keg with 3-4 gravity points remaining (spunding) being sure to leave behind some wort to swirl up the remaining flocculated yeast and transfer that to a mason jar with a plastic lid (they leak and allow gasses to escape even when sealed). I do this using glass carboys as my primary fermenters.
Topic: Help with Apple-like off-flavor (Read 2368 times)
