I'm planning on using yeast from a bottle in a future batch of beer. The bottle is a reliable source and I know the success rate isn't 100%, so don't worry about any of that. My questions are more around timing and amount.
I plan to pitch the slurry from the (chilled) bottle into 400ml of 1030 wort (that's been boiled for 10 mins). I will leave this until fermentation is completed (7 - 10 days). I will then decant the liquid from the yeast slurry and pitch the slurry into 1.5 litres of 1030 wort. Leave the 1.5 litre mixture for 24 hours and then pitch into my batch.
I'll look for signs throughout the process that the yeast is doing what it should. The 1.5 litres is based on calculating via Mr Malty the amount required for a 20 litre batch of beer (at 1048).
Before I go an make a mistake ... does this approach sound sensible/correct?
How long could I sensibly leave the 400ml starter for before I pitch into the 1.5 litres? If my brewday moves, I might need to delay using the yeast. I'm assuming that (as with a normal brew) you can leave it on the yeast for 2 weeks without any negative impact.
Thanks.





