Scaling up from a colony

I am preparing to start my own small yeast bank and I was wondering what is the optimal method for scaling up to a starter from a single colony.

  • What step sizes should I use?
  • What strength of wort should I use?
  • How long should it take for each step?

For the sake of an example, what would be the optimal path to get from a single colony on a plate to a starter suitable for pitching into 100l of 1050 wort?

Edit for clarity: By optimal I mean giving me the smallest pitchable starter, for the required number of cells, and having cells at the highest viability and vitality when pitching.

Topic yeast-cultures yeast-starters yeast homebrew

Category Mac

1
answered at

What I have pieced together so far: (as I dig up more I will expand this)

For 100l at 1050 I would require ~800 Billion cells +/- 10%. [http://homebrewacademy.com/stepping-up-a-yeast-starter/ ]

To grow cells from a slant would require me to scale the starter up first into a 10-15ml starter and from there scale around 1:6 times each step, so 10ml -> 50ml -> 250ml -> 1.25l -> 5l.

Each step should be allowed to ferment for 12-18 hours at 22C +- 2C with 8 hours to sit in the fridge (overnight) to force floccuation. Then pour off the bad tasting starter beer. Re-pitch the slurry into the next sized vessel and top up with fresh DME/nutrient solution. [http://www.mrmalty.com/starter_faq.php ]

The solution for the starter should be between 1030 and 1040 with the addition of yeast nutrients, and oxygen if you have it. If not a stir plate will force off CO2 and help dissolve more oxygen, failing these shaking every hour or so will work but be a bit slower and stress the yeast more. Pushing you more towards the 18 hour mark for each step.

So for a healthy pitch into a 100l batch it would optimally take 5 days to scale up ready for pitching.

1
answered at

You want to grow the slant up to about 100b cells by a mini starter, I start with 500ml 1.040 with nutrients.

Then treat that as I would a new pack of yeast.

Each step up of a starter takes 12-24 hours generally. Stirplate will help a lot to give more growth in shorter times.

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