I'm curious how you guys who brew 10+ gallon batches deal with creating enough yeast. I'm toying with the idea of upgrading my capacity to handle 10 gallon batches, but I am a little unsure about how I should handle my starters. For example, when I'm building up yeast for a typical 5 gallon lager batch, I've got a 4 liter starter on a stir plate (in a 5 liter flask), and I feel like that's _barely_ enough yeast.
Two stirplates/flasks is an option, but that's a lot of work.
One easy option is 2 vials/packs of yeast in your starter. I just made a 1.070 ale and only needed 2 vials in a 2.5 L starter according to MrMalty.
Another is to make multi-step starters. Making a 2L starter and then pitching that into another 2L will grow significantly more yeast than starting with a 4L starter. The Wyeast pitching rate calculator is good for calculating 2-step starters.http://www.wyeastlab.com/hb_pitchrate.cfm