dunbruha
Well-Known Member
I am getting ready to start using liquid yeast, and I have been doing a lot of reading about starters and yeast storage methods. I am a bacteriologist by training, but I am discovering that yeasts grow quite differently than bacteria
Id appreciate it if folks would comment on what I am planning, as I havent really seen anything quite like what I am thinking
My goal is to develop a system that produces a consistent supply of yeast for the minimal cost, without having to deal with agar slants (and having to perform multiple step-ups).
Yeast storage
1. Open a fresh tube of yeast. Im going to assume 75% viability, or 75B cells total. Im guessing there is about 30-35 ml of slurry in the tube.
2. Using a sanitized pipet, add 3 ml of the yeast slurry to vials containing 3 ml of sterile 20% glycerin. Put in fridge for 24h, and then freeze. Im estimating I can get 10 vials from each tube, with each vial having 7B cells.
Starter preparation
1. Thaw a vial to room temperature, then add to a sanitized flask containing 1 quart of sterile wort (1.036) plus some yeast nutrient. Incubate on a stir plate at 77*F for 24h.
2. Add this culture to 1.5L of wort (1.036, or higher for high-gravity beers). Incubate again on stir plate @ 77*F for 24h. Cold crash, then pitch. I am guesstimating that I would have approximately 300B cells at this point (based on the Braukaiser - Stir plate option in the Brewers Friend yeast calculator).
What do you think? Do you see any potential problems, or any improvements? Thanks in advanceI have learned so much from reading HBT!
My goal is to develop a system that produces a consistent supply of yeast for the minimal cost, without having to deal with agar slants (and having to perform multiple step-ups).
Yeast storage
1. Open a fresh tube of yeast. Im going to assume 75% viability, or 75B cells total. Im guessing there is about 30-35 ml of slurry in the tube.
2. Using a sanitized pipet, add 3 ml of the yeast slurry to vials containing 3 ml of sterile 20% glycerin. Put in fridge for 24h, and then freeze. Im estimating I can get 10 vials from each tube, with each vial having 7B cells.
Starter preparation
1. Thaw a vial to room temperature, then add to a sanitized flask containing 1 quart of sterile wort (1.036) plus some yeast nutrient. Incubate on a stir plate at 77*F for 24h.
2. Add this culture to 1.5L of wort (1.036, or higher for high-gravity beers). Incubate again on stir plate @ 77*F for 24h. Cold crash, then pitch. I am guesstimating that I would have approximately 300B cells at this point (based on the Braukaiser - Stir plate option in the Brewers Friend yeast calculator).
What do you think? Do you see any potential problems, or any improvements? Thanks in advanceI have learned so much from reading HBT!