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General Category => Yeast and Fermentation => Topic started by: HydraulicSammich on March 22, 2013, 05:54:08 PM

Title: Stepped yeast starters
Post by: HydraulicSammich on March 22, 2013, 05:54:08 PM
I am in a bit of a quandary with a yeast starter for an English Pale Ale with gravity of 1.055, 5.5 gal, and stir plate.  I have one packet of Wyeast 1028 with a date of Dec 11, '12.  I anticipated doing a two step starter.  When I plug it into Mr. Malty, it maxed out, with stir plate at 2 packets in near 2 liters.  So, I need to step up.  Then I plugged it into YeastCalc, same parameters, it suggests 1 packet, 2 liters, good to go.  I am either missing something or this is a fair discrepancy.  I have read W & Z Yeast book and other books concerning starters but I am still a bit in the dark about the second step procedure for a starter.  Any help would be appreciated.  Thanks.
Title: Re: Stepped yeast starters
Post by: mainebrewer on March 22, 2013, 06:49:55 PM
If there is a process built into Mr Malty for step starters, I have not found it.
I don't know what your max capacity is for making a starter. You mention a 2l flask.
If you can make a larger starter volumn, try moving the yeast growth slider to max yeast growth.
That may reduce the number of packets needed to one but will increase the volumn.
Or, you can put in all the data just as you've done, then reduce the gravity of the beer until you get to 1 packet.
Make whatever volunm starter is indicated using the one packet.
Ferment it out.
Then change the data to reflect brand new yeast and the actual gravity of the beer you want to make.
Make whatever size starter is indicated and let that ferment out.
Decant and pitch.
Title: Re: Stepped yeast starters
Post by: davidgzach on March 22, 2013, 06:59:27 PM
Mr Malty drops the viability to 26% while yeastcalc drops it to 47% for the same date.  They used to use the same formula but looks like yeastcalc changed.  If you are concerned, average it out and make a little bigger starter.

Dave
Title: Re: Stepped yeast starters
Post by: kylekohlmorgen on March 22, 2013, 07:06:30 PM
www.yeastcalc.com
Title: Re: Stepped yeast starters
Post by: HydraulicSammich on March 22, 2013, 07:09:45 PM
Quote
Mr Malty drops the viability to 26% while yeastcalc drops it to 47% for the same date.  They used to use the same formula but looks like yeastcalc changed.  If you are concerned, average it out and make a little bigger starter.

Well, that is exactly what I saw.  Thanks for the comment.
Title: Re: Stepped yeast starters
Post by: cornershot on March 22, 2013, 07:51:47 PM
I use the yeast calculator on the Brewzor Android app. It says you have 28% viability and you need 212 billion cells. A 1liter starter on a stir plate would give you 114B and a second 1L would give you 263B. Nice free app. Hope it helps!
Title: Re: Stepped yeast starters
Post by: Kaiser on March 22, 2013, 11:24:17 PM
There is more discrepancy to these yeast pitch calculators than you think. I'm talking about 2x and more.

In my experience one gram of grows about 1.4 billion cells when a stir plate is used. That is true over a fairly wide range of initial pitching rates.

Kai
Title: Re: Stepped yeast starters
Post by: klickitat jim on March 23, 2013, 12:39:39 AM
I recently did a Belgian 1.090 with a Wyeast Belgian strong that born Aug `12. The software told me it was dead. It never grew when I popped it. I started it in 2 qts 1.040. Added 2 qts two days later and again in two more days. Two days after that I crash cooled, decant and pitch. It nearly popped the lid with a 1/2" blowoff tube. ..

"Freedom is temporary unless you are also Brave!" - Patriot

Title: Re: Stepped yeast starters
Post by: a10t2 on March 23, 2013, 02:58:38 PM
In my experience one gram of grows about 1.4 billion cells when a stir plate is used. That is true over a fairly wide range of initial pitching rates.

Just to extend that, 1.4 billion/g works out to about 1.8 L of 10°P wort for this pitch. Assuming 50 billion cells in the pack and 65% attenuation in the starter wort.