by squirt in the turns » Monday Mar 28, 2011 11:56 am
D'oh, I'm replying even later than jords. There is indeed plenty of good info around on this topic. Plenty of debate too.
Dave, your 500 ml of diluted wort will be around 1.023, a little weaker than is recommended normally, but it's probably not a bad thing in this situation. Better than too strong, in any case. If I recall correctly, I started off the sediment from 2 tallies in around 100 ml of 1.030 wort - not much at all, but the yeast are probably in a very fragile state at this stage.
Keep the source stubbies chilled and undisturbed to encourage the yeast to settle, sanitise the tops of them, gently pour off the beer (remember to drink it!) leaving enough to swirl around to dislodge the sediment when you pitch it. I would have the 100 ml starter wort chilled too, to reduce thermal stress on the yeast, and allow it to come up to ferment temps slowly. Mine didn't really look like it did much at this stage, just the merest hint of krausen. I fed it another 100 ml or so a couple of days later, and another 500 ml a few days after that, by which time it was obviously starting to enjoy itself and producing krausen every which-way. At this point I think I chilled it again so that I could pour off the spent beer and step it up to a final volume of 2 L - I was using a 2 L flask.
Starting small obviously means more steps and thus more chances for infection to get in or other stuff to go wrong, but if your sanitation is up to scratch this is preferable to potentially stressing the yeast.