I've been using Wyeast Green Belt (from agar slants) for the last several brews. It's a pretty good APA/IPA yeast but I was getting low on slants so I picked up another Green Belt smack pack. I'd like to aliquot it into some volume (say 25 ml) in addition to making a number of new slants.

Smack packs contain 125 ml of yeast slurry (equivalent to 25 ml per gallon of wort in a 5 gal batch). This is a fermentation pitch, and not appropriate for growing yeast.

Question: How much of the smack pack would be appropriate for a 1L or 2L starter that's grown up 24hr on a stir plate?

Variation: Into what initial volume of starter wort would I pitch my 25 ml aliquot to do a step starter?

I have Zainasheff & White on the subject, but I got lost about the middle of the discussion.

Charlie (has some 50 ml Pyrex culture tubes)

I think the minimum recommended size starter for a vial or smack pack for growing cells is 2L, so you could use half of it for a 1L and the rest in slants.

Or use 25ml in a 0.4L starter.

The general rule is you want a 10x volume increase so you'd go from 25mL to 250mL

Roger that. Thanks guys.

Charlie

I aliquoted the smack pack into five sterile 25 ml tubes today (there was a little over 125 ml in there), and innoculated two starters. At +6hr the 25ml + 0.4L strategy seems to be working.

I appreciate the feedback.

Charlie