[BrewQwest]

I am trying to find out the yeast counts in dry yeast and math is not one of my strong points.... There is another thread which quotes Clayton Cone of Danstar Lallemand stating that each gram of the dried yeast contains 20 billion live yeast cells. First off, I find that extremely hard to believe. 20 billion in one gram? So I went onto their web site. See here for the spec sheet on their Nottingham yeast: http://www.danstaryeast.com/sites/default/files/nottingham_datasheet.pdf .. Now, Item 2 states they have more than 5 Billion cells (5 x 10⁹ =5 billion right?) per gram but then Item 4 of that pdf file states 100 grams in 100 hectoliters gives you a density of 5 - 10 million cells per milliliter. This is much more than Item 2 states, but even this amount could be equivalently scaled to 10 grams at 10 liters (or only 2.64 gallons). Which would mean I need 20 grams for 5 gallons just to give me a max of 10 million cells per milliliter. And 10 million cells per milliliter is only good for inoculating a 10^o Plato wort (figuring 1x10⁶ x Plato^o = cells per milliliter) which is roughly only 1.040 gravity. Also, if you look up SafeAles S-05 pdf sheet here: http://www.fermentis.com/FO/pdf/HB/EN/Safale_US-05_HB.pdf you will find only 6 billiion yeast cells per gram. Meaning an 11 gram sachet would only have a maximum of 66 billion yeast cells! Figuring this backwards: 66,000,000,000 / 3785ml per gal / 2.5 gal = 6.974 million cells per milliliter. Which is a proper pitch rate for only 2.5 gallons of a 7^o Plato wort (approx only 1.028 gravity). Where did all the yeast go? Or am I computing something drastically wrongly here??  cheers!!

[denny]

I suggest emailing them and asking them directly.

[BrewQwest]

denny and others, typically what values has everyone used for a cell count on these dry yeast sachets?

[denny]

To tell the truth, I don't worry about it.  I just know that it's enough!

[maxieboy]

To tell the truth, I don't worry about it.  I just know that it's enough!

You mean you don't have a page full of equations to state your case? 

[johnf]

I've noticed this as well. If the lower number (that all of the manufacturers have in their fact sheets) is correct, then a packet of dry yeast has fewer cells than an XL Smack Pack or a WL Tube. If the higher number (from JZ's pitching calculator - which he says are based on counts, and old correspondence with Dr. Cone) is correct, then they have much more. I've found S05 to be very estery compared to 1056 based on what the higher number for the dry yeast cell density would suggest is a comparable pitching rate and have wondered if this was because the lower rate was correct. At the end of the day I stopped caring since if I have to use 3 times as much dry yeast as I thought I did I'm not going to use it anyway (and at the JZ recommended rate, I was not happy with it).

[BrewQwest]

I've noticed this as well. If the lower number (that all of the manufacturers have in their fact sheets) is correct, then a packet of dry yeast has fewer cells than an XL Smack Pack or a WL Tube. If the higher number (from JZ's pitching calculator - which he says are based on counts, and old correspondence with Dr. Cone) is correct, then they have much more. I've found S05 to be very estery compared to 1056 based on what the higher number for the dry yeast cell density would suggest is a comparable pitching rate and have wondered if this was because the lower rate was correct. At the end of the day I stopped caring since if I have to use 3 times as much dry yeast as I thought I did I'm not going to use it anyway (and at the JZ recommended rate, I was not happy with it).

Thanks John, I also noticed this the last few times I used dried yeast. Lag times seem to have increased and tastes of underpitched fermentations have begun to appear. And these are on 1.045 - 1.050 OG's...This is why I began to question the yeast counts and why I bothered to consult the tech sheets. It could be that I got my hands on some bad packs but expiration date isn't until the end of 2011..  I did take Denny's advise and have emailed the appropriate individuals (for the second time) but do not expect any more of a reply than the first time.  Maybe if my last name was Conn it would carry more weight  ...  cheers all !!

[denny]

Maybe if my last name was Conn it would carry more weight  ...  cheers all !!

That and 2 bucks will get ya a cup of coffee....

[tschmidlin]

Maybe if my last name was Conn it would carry more weight  ...  cheers all !!

That and 2 bucks will get ya a cup of coffee....

You get discounts on coffee too?!  Oh, to be Denny Conn . . . .

[BrewQwest]

Lo and behold I got a response from Danstar/Lallemand...  It seems their information in item 2 of the pdf file is correct.  5 billion cells per gram which is enough to innoculate 10 liters.... So it appears it does take 2 sachets for a 20 liter batch (approx 5.3 gallons)... They also said they are in the process of repackaging their yeast for the proper pitch rates.... Interesting......cheers!!

[maxieboy]

Wow, interesting.