Homebrewers Association | AHA Forum

General Category => Yeast and Fermentation => Topic started by: mmitchem on August 15, 2012, 11:35:22 am

Title: Pitching Yeast by Weight...
Post by: mmitchem on August 15, 2012, 11:35:22 am
Greetings All!

I have read from a few sources (Kai's blog most recently) that pitching yeast by weight is the way to go. I can definitely see where this would be advantageous, especially as my batch sizes increase. Is there a quick and dirty way to estimate yeast cell count based on weight? Thick slurry vs thin slurry? Thanks for the help in advance!
Title: Re: Pitching Yeast by Weight...
Post by: AmandaK on August 15, 2012, 12:57:10 pm
I would use Mr. Malty's pitching rate calculator. http://www.mrmalty.com/calc/calc.html (http://www.mrmalty.com/calc/calc.html)

The third tab has a slurry calculator.
Title: Re: Pitching Yeast by Weight...
Post by: Kaiser on August 15, 2012, 12:58:05 pm
Jamil has some numbers in his Pitching Rate Calculator. I have some numbers too and plan to publish them as a follow-up to the blog post.

For a well flocculating lager yeast I get about 4-5 Billion cells per gram in freshly propagated yeast and 2-3 B/g in yeast harvested form a primary.

The numbers seem to be a bit different for Ale yeasts. I have to check the few data points I have at home.

Kai
Title: Re: Pitching Yeast by Weight...
Post by: mmitchem on August 15, 2012, 01:26:12 pm
I have used Mr Malty for most of my starter calculations over the last few years and also have noticed the slurry tab as well. It has always done me right :)

Kai - I mostly do lagers as well and saw the billions per gram calculation in your blog post. I must admit that I do a lot more lagers than ales at this point so that information is top notch. With that in mind to pitch around 500 billion cells I am looking at a thick slurry of around 111-112 grams. Does that sound about right?

Also, what are the differences in weight with ale yeast? More cells? Less cells? If I were going along with the 4.5 billion per gram assumption it would put me at pitching 55-56g for 250 billion cells. Is that a safe assumption?