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General Category => Yeast and Fermentation => Topic started by: donsmitty on April 19, 2013, 01:42:53 PM

Title: Yeast Starter Cells Created
Post by: donsmitty on April 19, 2013, 01:42:53 PM
If I start a 1 quart yeast starter using Wyeast 1056 (100 Billion cells), how many cells can I expect to gain?  I use BeerSmith2 and it tells me I need a starter plus 1 pack for 237 Billion cells.  I'm assuming it means that I need to create a yeast starter in addition to another yeast pack.  Since each yeast pack is 100 Billion cells I guess my gain from the starter is 37 Billion cells?  Am I understanding this correctly?  BS also says if I don't use a starter then I would need 3 yeast packs.  Is there a way to know how many cells I'm really gaining from a yeast starter? 
Title: Re: Yeast Starter Cells Created
Post by: troybinso on April 19, 2013, 02:36:05 PM
There is a great yeast resource online published by Jamil Zainasheff.

http://www.mrmalty.com/calc/calc.html (http://www.mrmalty.com/calc/calc.html)

You can play around there with starter size and expected growth. My general procedure for a yeast starter of an average gravity 5 gallon batch would be at least 2 liters of approx 1.035 wort for one package of yeast. My understanding is that you don't really get much growth with a one liter starter.
Title: Re: Yeast Starter Cells Created
Post by: duncan on April 19, 2013, 03:05:22 PM
I was reading the book Yeast just the other day, and they have a chart with different inoculation rates to show that starter growth is dependent on starter volume and yeast cells pitched (not just one or the other). A quart starter, which is roughly 1 liter, with 100 billion cells pitched will grow by roughly 50%, resulting in about 150 billion yeast cells.

The MrMalty calc is definitely a handy tool to use, too.
Title: Re: Yeast Starter Cells Created
Post by: a10t2 on April 19, 2013, 03:48:00 PM
Is there a way to know how many cells I'm really gaining from a yeast starter?

Not without a cytometer, no. But Kai's done some experiments recently for different inoculation rates and oxygenation techniques and found that the variation isn't all that large. Roughly speaking, every liter of 10°P starter wort will grow about 100 billion cells using a stir plate, and about half that without one.

http://braukaiser.com/blog/blog/2012/10/08/yeast-growth-experiments-some-early-results/
Title: Re: Yeast Starter Cells Created
Post by: donsmitty on April 19, 2013, 08:40:33 PM
Thanks for all the replies...I'll check out the site as well.  I am using a stir plate and my primary is like a volcano so I must be getting good cell counts.