Timing for stepping up a stirplate starter?

I need to step up in increments since I only have a small amount of WLP001 yeast saved from the last batch. Any recommendations on timing of the steps?

Intent is to pitch / stir-plate till ? / crash 24hrs / decant / repeat until I get to 2L.

With the very last stepping, I want to pitch at high krausen. How do you tell when high krausen is with a stir plate?

How much is a small amount?

Wait for the color to change. It will get markedly lighter (creamy, like when cream is added to coffee) when the yeast blooms.

bolts said:

I need to step up in increments since I only have a small amount of WLP001 yeast saved from the last batch. Any recommendations on timing of the steps?

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From info I have encountered, a starter on stir plate at temps around 70F should finish reproduction in ~ 24 hours.

bja said:

How much is a small amount?

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~3/4" yeast sediment in the bottom of a reused white labs vial. It was captured from a non-decanted 2L stir plate starter (1 generation).

I should add that I'm intending to step in about 5 - 10x volume increments. First stepping will be quite small (~10x the volume of just the yeast), then up from there after decanting and stepping again.

rcrabb22 said:

From info I have encountered, a starter on stir plate at temps around 70F should finish reproduction in ~ 24 hours.

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+1 After 24 hours I turn the stir plate off. Then I let it settle for a day or two, decant and add fresh wort and turn the stir plate back on for 24 hours

24 hours sounds good in between steps, but don't decant between the steps. That would throw away a lot of the yeast (and it would be the best yeast that's still in suspension that gets thrown away) even if you chill for 24 hours.

-a.

My process (I grow yeast from 15ml frozen tubes which contain about 3ml of yeast slurry). I use a 4L flask on a stir plate.

0.25 Liter starter. 48 hours to exponential growth.
2L stepup. 24 hours to growth.
2L stepup. 24 hours to growth.
decant. 2 days. 35F
2L stepup. 24 hours to growth.
2L stepup. 24 hours to growth.

passedpawn said:

My process (I grow yeast from 15ml frozen tubes which contain about 3ml of yeast slurry). I use a 4L flask on a stir plate.

0.25 Liter starter. 48 hours to exponential growth.
2L stepup. 24 hours to growth.
2L stepup. 24 hours to growth.
decant. 2 days. 35F
2L stepup. 24 hours to growth.
2L stepup. 24 hours to growth.

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So, tou're using about 2 pounds of DME to make starter wort?

bja said:

So, tou're using about 2 pounds of DME to make starter wort?

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Yep. 1 cup per liter. I buy it in large quantities, but it is still expensive. I'm growing yeast for 10 gallon batches so I like to make a lot. Hell, I've made 2 gallons of "beer" by the time my starter is done!

I have also stored wort for starters... I need to get a large pressure canner and get back to that!