Ah! The signature is out of date. The Scottish Heavy went wrong! Left it on the yeast for too long and it ended up VERY sulphury. :sick:
Re-using the yeast cake is easy and the first step in getting several generations of use out of a batch. Syphon the beer off leaving just a bit of the wort in with the yeast. The cake shouldn't be covered, but should still be nice and 'moist'.
Make the new wort in a separate FV and aerate very well (Beat the hell out of it with a paddle and whisk!). The tricky bit is not to shock the yeast, so add four ladels of the new wort to the cake and mix gently. Leave 3 minutes and then repeat, adding an extra ladel each time. Once you get to 15 mins (by which time you will be adding 8 or 9 ladels), then the yeast cake should be at the same temp as the new wort. Simply pour the rest of the new wort straight onto the cake.
Ta-da! Job done. You can get away with not bringing it slowly up to temp, but I have always found it good practice and it keeps it all healthy.
For 3rd and 4th generations for subsequent brews, you need to 'clean' the cake to remove dead yeast and then split into starter batches. I have rarely got that far, but now the price of yeast has gone up, I may think about it!
Hope that helps!
OH! Forgot to say - put the lid from the new FV onto the one that has the yeast cake when you are done. Good to have a clean lid.
