Author Topic: Yeast starter, multiple packs  (Read 654 times)

Offline yso191

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Yeast starter, multiple packs
« on: February 06, 2014, 04:08:47 PM »
I am going to start a starter for a RIS I'll brew in a week and a half.  The OG is calculated to be 1.099.

BeerSmith's yeast calculator says I'll need 363.3 billion cells.  Out of the 2 LHBS in town one had 3 packs of Denny's Favorite, but they were old (1@ 10/14/13, and 2 @11/13/13).  BS says all I need in addition to the 3 packs is a 1.5  liter starter.

Should I prepare a standard 1.5 liter starter, then dump all 3 packs in my 2 liter flask?  What would you do?
Steve
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Offline morticaixavier

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Re: Yeast starter, multiple packs
« Reply #1 on: February 06, 2014, 04:23:27 PM »
I am going to start a starter for a RIS I'll brew in a week and a half.  The OG is calculated to be 1.099.

BeerSmith's yeast calculator says I'll need 363.3 billion cells.  Out of the 2 LHBS in town one had 3 packs of Denny's Favorite, but they were old (1@ 10/14/13, and 2 @11/13/13).  BS says all I need in addition to the 3 packs is a 1.5  liter starter.

Should I prepare a standard 1.5 liter starter, then dump all 3 packs in my 2 liter flask?  What would you do?

I would create three ~1 liter starters and pitch one packet into each. but I have a pathalogical fear of underattenuated RIS since I had a bad experience with the last one I brewed (my only bottle bomb so far).

As I understand it the online calculators don't do a great job of modeling the differences in growth given starting population although I seem to remember that Yeast Calc is better than mr malty at that.


**EDIT TO ADD**
poking around on yeastcalc (still available at yeastcalculator.com) says you should be okay with a 1.5 liter with all three packs. just under the 350 billion is recomends.
« Last Edit: February 06, 2014, 04:26:57 PM by morticaixavier »
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Offline yso191

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Re: Yeast starter, multiple packs
« Reply #2 on: February 06, 2014, 05:31:12 PM »
Thank you!
Steve
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Offline erockrph

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Re: Yeast starter, multiple packs
« Reply #3 on: February 07, 2014, 06:25:16 AM »
Is a starter that small for 3 packs really going to give you enough healthy growth to be worthwhile? I recall some talks from recent NHC's (Neva Parker's IIRC), where she basically said it's not recommended to make a 1-liter starter for 1 pack because the growth you'd get is minimal. You'd be better off just pitching the yeast right from the pack, since yeast from the lab is almost always going to be healthier than yeast grown from a starter at home.

If you're constrained to a max of 1.5 liters for your starter size, I'd consider making a starter with one pack, then pitching the other 2 packs into the wort without making starters for those.
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Offline morticaixavier

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Re: Yeast starter, multiple packs
« Reply #4 on: February 07, 2014, 08:31:05 AM »
Is a starter that small for 3 packs really going to give you enough healthy growth to be worthwhile? I recall some talks from recent NHC's (Neva Parker's IIRC), where she basically said it's not recommended to make a 1-liter starter for 1 pack because the growth you'd get is minimal. You'd be better off just pitching the yeast right from the pack, since yeast from the lab is almost always going to be healthier than yeast grown from a starter at home.

If you're constrained to a max of 1.5 liters for your starter size, I'd consider making a starter with one pack, then pitching the other 2 packs into the wort without making starters for those.

I thought of that as well, because the packs are all pretty old though I was thinking it might be okay.

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Offline S. cerevisiae

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Re: Yeast starter, multiple packs
« Reply #5 on: February 09, 2014, 04:29:07 PM »
The yeast culture in a White Labs vial is in the stationary phase, which means that the cells have low ergosterol and unsaturated fatty acid (UFA) reserves. If the culture has been in storage for a while, then the cells have depleted a large percentage of their glycogen stores, which means that they are a stone's throw away from death.  Anyone who has pitched a White Labs vial into a stirred 1L 10% w/v  (1.040 S.G.) malt sugar solution can attest that one can expect to at least triple the cell count.   If one pitches the starter at high krausen, one will be pitching yeast cells that have sufficient ergosterol and UFA reserves to handle the high osmotic pressure imposed upon their cell walls by a 23.5% w/v (1.099 S.G.) wort.

If the O.P. is willing to perform a stepped protocol, then he can get away with using only one vial of yeast.  The first step should be pitched into 500mls of 10% w/v wort (adding 1/16 to 1/8 tsp of yeast nutrient is a good idea).  The starter should be placed on a stir plate and incubated for 24 to 36 hours before chilling to precipitate the yeast cells.  The supernatant (clear liquid) is then decanted, and the culture is pitched into 1.5 to 2.0 liters of 15% w/v (1.061) wort and placed on a stir plate for 24 to36 hours before chilling to force the yeast cells out of suspension, decanting the supernatant, and pitching the culture into one's batch of beer.
« Last Edit: February 09, 2014, 07:16:24 PM by S. cerevisiae »
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Offline yso191

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Re: Yeast starter, multiple packs
« Reply #6 on: February 09, 2014, 04:53:57 PM »
Wow.  Supernatant.  I'm a bit of a word guy, and I haven't heard of that one.  I guess it just goes to show that I'm not a scientist.  It does seem like a good idea but I am running out of time.  I'll get started tonight.  Thanks for the input!
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Offline S. cerevisiae

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Re: Yeast starter, multiple packs
« Reply #7 on: February 09, 2014, 07:22:24 PM »
Supernatant is a fairly common word in yeast management.
Mark V.

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Separate the National Homebrew Conference from the National Homebrew Competition

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Offline yso191

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Re: Yeast starter, multiple packs
« Reply #8 on: February 10, 2014, 07:40:17 AM »
Supernatant is a fairly common word in yeast management.

I would really like to job shadow that position for a while!
Steve
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Offline a10t2

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Re: Yeast starter, multiple packs
« Reply #9 on: February 10, 2014, 09:05:26 AM »
Anyone who has pitched a White Labs vial into a stirred 1L 10% w/v  (1.040 S.G.) malt sugar solution can attest that one can expect to at least triple the cell count.

Only if the initial cell count is low. A liter of 10°P wort (60-70 grams of fermentable extract) is going to grow about 150 billion cells under optimal conditions. If the starting population is 60 billion cells, then yes, it will at least triple, but that isn't going to hold true for higher starting cell densities.

Steve, I'd get one of the newer packs, which should be something like 60-80% viable if they were stored properly, and pitch it into a 3 L starter.
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