• Welcome to the new forum! We upgraded our forum software with a host of new boards, capabilities and features. It is also more secure.
    Jump in and join the conversation! You can learn more about the upgrade and new features here.

Dry yeast cell counts

domanah

Master Brewer
Joined
Mar 11, 2017
Messages
64
Reaction score
0
Hello, when calculating yeast pitching rates I get "conflicting" info wrt cell counts of dry yeast. Some sources suggest you get 20 billion per gram vs the manufacturers' >6 billion per gram. Any wisdom/advise?
 
If I remember correctly, the 20 billion cells per gram claim comes from Jamil Zainasheff.  While he has done a lot of work in the area of cell counts and yeast starters, he has not published any of it directly (some may be in the book he co-wrote with Chris White titled 'Yeast').  Given that, I take it as anecdotal and not a verified claim. 

The yeast manufacturers usually err on the safe side for cells per gram claims, but I would think their counts are much more reliable in the long run.  It is always good to double check the manufacturer's specifications, as some of the latest releases are lower (specifically, the New England East Coast Ale Yeast from Lallemand) based upon their data sheet.
 
Thanks for the reply. That means I would need about 4 packs of 11g dry yeast for a 25l batch with a SG of 1.040?
 
If you go to the 'starter' tab in your recipe and update the yeast entry to reflect the packaging date on your yeast, the program will give you a cell count needed for that specific batch and the number of packets of yeast needed to reach that quantity.

 
First, I'm shocked that you haven't gotten the response of "it's all a guess unless you're performing cell viability/vitality counts"

because it is.

Fermentis claims their packs have approximately 10b cells per gram, and guarantee 6b cells per g. therefore an 11g pack could have between 66b and 110b cells per pack.

"The recommended pitching rate for our Lager strains in a first use of active dry yeast is from 80 to 120 g/hl, corresponding to 7 to 11 million cells/ml and for Ale from 50 to 80 g/hl corresponding to 3 to 5 million cells/ml.

It is linked to the fact that our standard dosage in our packaging is around 10?10^9 cells/gr. On packaging, we are not mentioning the standard results but the absolute minimum guarantee so 6?10^9 viable cells/gr."


If you were to pitch at .75b/ml/p you would want approx 190b cells, therefore anywhere between 1.5 and 4 packs would be "required"

The 'starter' tab also gives you a rough approximation based on many studies.
 
Back
Top