Come enter the BrewHardware Giveaway!


Home Brew Forums > Home Brewing Beer > Fermentation & Yeast > Viable Cells: dry vs liquid
Reply
 
LinkBack Thread Tools
Old 04-13-2014, 02:09 PM   #1
Blitzkrieg
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
Blitzkrieg's Avatar
Recipes 
 
Join Date: Jan 2014
Location: Shannon, Qubec
Posts: 134
Liked 24 Times on 18 Posts
Likes Given: 1

Default Viable Cells: dry vs liquid

So I keep reading this on HBT that it seems to be common knowledge that an 11.5g pack of dry yeast has approximately double the viable cells of a vial or pack of liquid yeast. Where does this come from? A pack of US-05 (arguably one of the most popular dry yeast strains) ships from the lab with just 69 billion cells. Now I realize that the dry yeast will store better and stay closer to that 69 billion than a liquid would, but when I do my starter calculations with reasonably fresh yeast I always have more than 69 billion viable cells to start. Are we assuming that liquid yeast is always months old and therefore less than 34 billion cells? I'm intrigued...

__________________
Blitzkrieg is offline
 
Reply With Quote Quick reply to this message
Old 04-13-2014, 02:16 PM   #2
mtnagel
HBT_LIFETIMESUPPORTER.png
Feedback Score: 6 reviews
Recipes 
 
Join Date: Apr 2012
Location: Cincinnati, Ohio
Posts: 2,104
Liked 189 Times on 150 Posts
Likes Given: 175

Default

Good question. MrMalty.com will tell you there is about 220 billion cells per 11.5 g packet, but you are right, when you look up the specs on the fermentis website, there are in fact only 69 billion cells.

__________________
-Matt
mtnagel is offline
 
Reply With Quote Quick reply to this message
Old 04-13-2014, 07:56 PM   #3
Beezer94
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2009
Location: Harmony, PA
Posts: 585
Liked 15 Times on 13 Posts
Likes Given: 33

Default

The amounts listed are minimum number of viable cells at packaging. If you look hard enough you can find the resources where people used microscopes to count cells and found significantly more than the minimum.

__________________
RDWHAHB
Add more hops! Always add more hops
Beezer94 is offline
 
Reply With Quote Quick reply to this message
Old 04-14-2014, 01:52 AM   #4
mtnagel
HBT_LIFETIMESUPPORTER.png
Feedback Score: 6 reviews
Recipes 
 
Join Date: Apr 2012
Location: Cincinnati, Ohio
Posts: 2,104
Liked 189 Times on 150 Posts
Likes Given: 175

Default

Not saying you are wrong, but are you sure about the minimum part? This says typical analysis.

__________________
-Matt
mtnagel is offline
 
Reply With Quote Quick reply to this message
Old 04-14-2014, 02:05 AM   #5
boydster
Round Earther
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
boydster's Avatar
Recipes 
 
Join Date: Apr 2013
Location: , Maine
Posts: 2,804
Liked 754 Times on 518 Posts
Likes Given: 600

Default

Yes, I am sure that 69 billion is a minimum. Fermentis claims the packets are packaged with an average of 150 billion viable cells, and state that 69 billion is a minimum guarantee. The packets say > (greater than) 69 billion cells. It is a guaranteed minimum, so if you have a packet stored at room temp that is about to expire, you still have a baseline that you can expect. Seen experiments with US-05 viability by Sean Terrill for confirmation.

__________________

Check out these cool kits at Know How Brews & Foods!

Big Jim Walker IIPA
Allagash-ishhh White Ale
Happy Hoppy Blonde Ale

boydster is offline
 
Reply With Quote Quick reply to this message
Old 04-14-2014, 05:21 AM   #6
BigFloyd
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2012
Location: Tyler, Texas
Posts: 4,813
Liked 629 Times on 549 Posts
Likes Given: 575

Default

An 11g packet of dry yeast, according to microscopic counts, contains somewhere around 220+ billion cells.

From the Q&A on Danstar's website -

Question:
2) Setting aside viability, what is the typical actual total cell count per gram Nottingham?

I did a count some time ago, and though my methods are very crude and homemade (using estimates drop volumes), and may give errors, I arrived at a much higher count, around 20 billion/g. It did only one count, so there may have been error, but I am doubtful that my error is that large, or if the numbers you guarantee are rather on the low side to be safe? I never repeated the experiment so I could have been in error, but it would be nice if you can confirm what is the excepted actual total cell count, rather than the minimum guaranteed viable cell count)

Answer:
The viabilities mentioned on the technical data sheets are minimum viable cells per gram that we guarantee determined by plate count on YPD-agar. Usually the viability is higher. There is a slight difference in how resistant the different strains are to drying and rehydration. Usually ale yeast strains are more resistant than lager yeast strains.

You might also consider that you will find much higher cell numbers under the microscope than by plate count, even if you have 100 % viability because you do not always have a single cell forming a colony but rather two or more cells. For Nottingham yeast the average cell count under the microscope is around 20 to 30 billion cells per gram dry yeast.

__________________
Good Temp Control -----> Happy Yeast ------> Tasty Brew
BigFloyd is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Safe-overpitching / How do you know your actual number of viable yeast cells? Paradigm Beginners Beer Brewing Forum 3 04-03-2014 08:12 PM
How long does liquid yeast stay viable for use? Phipcice General Chit Chat 2 11-03-2012 08:43 PM
How to step 100b cells to 800b cells alfista Fermentation & Yeast 15 07-25-2012 04:11 AM
how many cells are here? Veedo Fermentation & Yeast 8 06-14-2012 03:11 AM
How many cells do you think I have? bottlebomber General Beer Discussion 4 11-24-2011 05:42 PM



Newest Threads

LATEST SPONSOR DEALS