Question on Stepping up Yeast - Home Brew Forums

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11-16-2012, 02:17 AM   #1
scubastan
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Nov 2011
Los Angeles, CA
Posts: 30
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Hi Everyone,

I have a question about stepping up yeast.
I have a un-opened vial of Whitelab 004 Irish Ale Yeast.

I plan on brewing a 5.25G Brown Ale with a Starting Gravity of 1.056

According to Mr Malty I need 205 Billions cells. I use a stirplate so it says I only need a 1L starter. I can just as easily go 2L or 3L starters.

A Whitelab vial has 35ml of liquid and ~70-120B cells.

Here is my question:
Using 70 Billion / 35ml you would get 2 Billion cells per ml of liquid.
2L is approximate 1/2 gallon. So using MrMalty Calculator. and entering
1.045 O.G. and 1/2 gallon I would need 20 Billion cells.

Does that mean if I use 10ml of yeast from the vial I will have enough yeast to ferment the starter? Then once its completely fermented on my stir plate I should have the 200 Billion cells I need for the 5gallon batch?

Sorry if this is confusing, but I hope you can follow along with what i'm trying to explain.

I know I could just use the entire vial to make my starter and be done with it. But if I only need 10ml of yeast from the vial, that means I can use that single vial for 3 different batches.

My current setup is to make larger starters then needed and then store the extra yeast for future use. But if I can use only 10ml I will save alot of valuable freezer space, and also risk less contamination.

11-16-2012, 04:09 AM   #2
Hex23
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Jun 2010
Illinois, Lake County
Posts: 990
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Quote:
 Originally Posted by scubastan So using MrMalty Calculator. and entering 1.045 O.G. and 1/2 gallon I would need 20 Billion cells.
I'm not 100% sure I follow your logic, but it sounds like your treating the upper volume field like it's the volume of your starter. That's supposed to be the volume of your main wort (i.e. the batch size)

11-16-2012, 04:11 AM   #3
Hex23
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Jun 2010
Illinois, Lake County
Posts: 990
Liked 61 Times on 59 Posts

Quote:
 Originally Posted by scubastan According to Mr Malty I need 205 Billions cells.
Don't forget to enter the date on the yeast. 205 Billion is the number if the yeast was made today (unlikely).

11-16-2012, 06:08 PM   #4
Scuba_Stan
Recipes

Aug 2011
Los Angeles, CA
Posts: 27

Figured out that answer to my question. Saw a link to a different Yeast calculator.
http://www.yeastcalc.com/

This calculator lets you enter the starting amount of yeast, and calculates the total you have based on the volume of your starter.

Alot of the other yeast calculators just go from the assumption that you use a fresh pack or vial and calculate based on ~100B cells.

Using the new calculator I can do the following.
If I draw 10ml of fresh yeast from the vial I should have about 20 Billion cells.
That is what I enter as my initial cell count.
then the 1st step will be a .5 Liter starter which will bring the count to 68 Billion.
Finally a 2nd step will be a 1.5 Liter starter which brings me to 224 Billion.

Basically I can now stretch a single Whitelab vial to 3 different brews without having to buy a new vial each time.

11-16-2012, 06:14 PM   #5
Golddiggie

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Dec 2010
Posts: 11,995
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The reality of attempting to extract JUST 10ML from the vial is not likely. The vials are known to foam up like mothers when opened, spewing yeast out immediately.

I would suggest making your starter, for the batch you're brewing, a bit larger and reserve some of the yeast from that. Make another starter with the reserved (right away) and then store that amount for future use.
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11-17-2012, 01:00 AM   #6
Mpavlik22

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Apr 2011
Pittsburgh, PA
Posts: 316
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That's an awful lot of work to stretch a vial for 3 batches.

I agree with gold diggie. Just make a larger starter and harvest a mason jar worth before pitching into your beer. You can easily get 10 generations out of a single vial (i wouldnt recommend gojng more). Here's it easily explained: http://www.homebrewtalk.com/entries/...-approach.html
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11-17-2012, 01:13 AM   #7
kh54s10

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Aug 2011
Tiverton, Rhode Island
Posts: 11,635
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Another reason you might not want to use only part of the vial is that the remainder has been opened and exposed to infection, and will be losing viability. The longer you save it the more likely it will get infected and the less viable it will be, requiring larger starters.

I make a starter that is larger than what I need and make 4 vials of yeast to freeze and store. I use 20ml vials with 5ml yeast, 5ml glycerine and 10 ml water.

I now have 7 varieties of yeast in my bank with US05 packets and two others I have not banked yet.

11-17-2012, 06:05 AM   #8
CryoEng
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Mar 2012
Rio Rico, AZ
Posts: 95
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Quote:
 Originally Posted by kh54s10 Another reason you might not want to use only part of the vial is that the remainder has been opened and exposed to infection, and will be losing viability. The longer you save it the more likely it will get infected and the less viable it will be, requiring larger starters. I make a starter that is larger than what I need and make 4 vials of yeast to freeze and store. I use 20ml vials with 5ml yeast, 5ml glycerine and 10 ml water. I now have 7 varieties of yeast in my bank with US05 packets and two others I have not banked yet.
I plan on starting this process during my next session. (About a week from now.)

Thanks for the information. Another enjoyable aspect of brewing.

Cheers