Originally Posted by Pappers_
I do this often, when brewing a big beer. After racking to the bottling bucket or keg, put the yeast in a sanitized Ball jar and use the next weekend.
Yes, I do this all the time. I just bought $42 worth of fresh yeast packages (about 7 packages). Those will last me until fall.
I'll make a starter, then use one package of yeast. When that beer is finished, I'll "wash" (rinse) the yeast a bit and pour into boiled and cooled mason jars. I'll use several pint jars for each yeast cake. Then, label them with a sharpie and put them in my beer fridge.
I use mrmalty.com's yeast slurry pitching calculator, and use about 1/2 pint jar for a 10 gallon batch.
Then do the same with each yeast strain.
I get about 10 5 gallon batches out of one package of yeast! I could even go longer, but I just use three or four pint jars and don't usually re-save unless it's a rare strain (like a seasonal).
Pitching onto an entire yeast cake would almost certainly be overpitching, though. Here's some food for thought: http://www.homebrewtalk.com/f163/why...t-cake-166221/
I have pitched onto an entire cake, when I first made a "small beer" to have enough yeast for a super high OG beer. That works really well with some lagers- to go from a 3 gallon batch of 1.043 lager to a 5 gallon batch of 1.085 dopplebock for example.