Dry Yeast Cell Count

[dabre4]

Yeast nutrition would have to be way more important than pitching rate.

Don't really agree with that, I will be adding yeast nutrient as it is an important addition with high gravity brews, but I'd say that pitching an ample amount of yeast is more important.

I know when counting cells with a hemocytometer (I'm assuming Jamil's method for counting) you can use methylene blue to "stain" dead or weak cells. Whether he did this or not during cell counts I can't say. If he was on White Labs side and was trying to damage the name of dry yeast, why the hell would he be saying that dry yeast packs have more viable cells then liquid, I would have thought he'd point at that they have less if that was the case.

I found this article which backs up what Jamil is claiming. This seems to suggest that dry yeast are very fragile and that during the re-hydrating stage (with the sprinkle method or re-hydrating separately) the cell walls are very weak, and that it takes up to 30 min for the yeast to build up their walls using the inbuilt glycogen and trehalose provided by the manufacture before they are strong enough to perform fermentation. As others have mentioned perhaps the manufacturer assumes that during this stage around 60 % of the cells will not be viable and only 40% will be good for fermentation. This bring the 20billion cells/g back into range the manufactures claim of 6 billion cell/g.

I get the feeling their is a bit of truth to both sides. I think Jamil and others who conduct cells count are in fact counting cells that won't be viable. I also think the manufacture assumes that under worst case conditions after re-hydration their will be at least 6 billion/g.

Another point is that the S05 packs claim their is enough yeast to ferment 20 - 30 liters. Let assume the best case scenario, a 20L low gravity brew with an OG of 1.035, the recommended pitching rate is around 130 billion. Let say more realistically a 24 L batch with an OG of 1.052, the recommended pitching rate is around 230 billion. A worst case scenario (within reason), a 30 L batch with an OG 1.060, the recommended pitching rate is around 330 billion. How can they claim their are only 69 billion viable cells in a pack (6 billion/g x 11.5g) and then claim you can pitch it in 20 - 30 L? Now if we assume their are 230 billion in a pack (20 billion/g x 11.5g), as Jamil and others claim, this seems to match the 20 - 30 L recommended volume by the dry yeast manufacturer. I would like to trust the manufacturer, but what they are claiming, to me, doesn't quite match up.

 

[Nick JD]

Don't really agree with that, I will be adding yeast nutrient as it is an important addition with high gravity brews, but I'd say that pitching an ample amount of yeast is more important.

I know when counting cells with a hemocytometer (I'm assuming Jamil's method for counting) you can use methylene blue to "stain" dead or weak cells. Whether he did this or not during cell counts I can't say. If he was on White Labs side and was trying to damage the name of dry yeast, why the hell would he be saying that dry yeast packs have more viable cells then liquid, I would have thought he'd point at that they have less if that was the case.

I found this article which backs up what Jamil is claiming. This seems to suggest that dry yeast are very fragile and that during the re-hydrating stage (with the sprinkle method or re-hydrating separately) the cell walls are very weak, and that it takes up to 30 min for the yeast to build up their walls using the inbuilt glycogen and trehalose provided by the manufacture before they are strong enough to perform fermentation. As others have mentioned perhaps the manufacturer assumes that during this stage around 60 % of the cells will not be viable and only 40% will be good for fermentation. This bring the 20billion cells/g back into range the manufactures claim of 6 billion cell/g.

I get the feeling their is a bit of truth to both sides. I think Jamil and others who conduct cells count are in fact counting cells that won't be viable. I also think the manufacture assumes that under worst case conditions after re-hydration their will be at least 6 billion/g.

Another point is that the S05 packs claim their is enough yeast to ferment 20 - 30 liters. Let assume the best case scenario, a 20L low gravity brew with an OG of 1.035, the recommended pitching rate is around 130 billion. Let say more realistically a 24 L batch with an OG of 1.052, the recommended pitching rate is around 230 billion. A worst case scenario (within reason), a 30 L batch with an OG 1.060, the recommended pitching rate is around 330 billion. How can they claim their are only 69 billion viable cells in a pack (6 billion/g x 11.5g) and then claim you can pitch it in 20 - 30 L? Now if we assume their are 230 billion in a pack (20 billion/g x 11.5g), as Jamil and others claim, this seems to match the 20 - 30 L recommended volume by the dry yeast manufacturer. I would like to trust the manufacturer, but what they are claiming, to me, doesn't quite match up.

Great post.

 

[sama]

as a guide mr malty and those fellas pitching rates seem to work,dosent it? well does for me..great info provided tho.

 

[bigfridge]

I found this article which backs up what Jamil is claiming. This seems to suggest that dry yeast are very fragile and that during the re-hydrating stage (with the sprinkle method or re-hydrating separately) the cell walls are very weak, and that it takes up to 30 min for the yeast to build up their walls using the inbuilt glycogen and trehalose provided by the manufacture before they are strong enough to perform fermentation.

I had the pleaseure of chatting about yeast with Dr Cone in the HBD Fortnight of Yeast (was it really way back in 2003 !) and the information about re-hydration was first paosted as part of this serries of questions.

There is no doubt that this procedure give optimal results with the Danstar yeasts. But as a followup (it may have been Wes Smith who posted it) this does not apply to all yeast manuafturers equally. Fermentis use a different manuafcturing process which is why they recommend to

"Re-hydrate the dry yeast into yeast cream in a stirred vessel prior to pitching. Sprinkle the dry yeast in 10 times its own weight of sterile water or wort at 23C 3C. Once the expected weight of dry yeast is reconstituted into cream by this method (this takes about 15 to 30 minutes), maintain a gentle stirring for another 30 minutes. Then pitch the resultant cream into the fermentation vessel.
Alternatively, pitch dry yeast directly in the fermentation vessel providing the temperature of the wort is above 20C. Progressively sprinkle the dry yeast into the wort ensuring the yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes and then mix the wort e.g. using aeration."

As MHB says follow the manufacturers directions - contrary to popular beleif they would much rather that you continue to buy yeast due to getting good results.

I know when counting cells with a hemocytometer (I'm assuming Jamil's method for counting) you can use methylene blue to "stain" dead or weak cells.

...

I get the feeling their is a bit of truth to both sides. I think Jamil and others who conduct cells count are in fact counting cells that won't be viable. I also think the manufacture assumes that under worst case conditions after re-hydration their will be at least 6 billion/g.

I don't have a reference handy, but I believe that methylene blue has been discredited as it also stains the glycogen in healthy cell walls. I can probably look up some stuff later if ya'all ask nicely.

HTH,

Dave

 

[dabre4]

Cheers Dave.

I think your right about methelyne blue, I've also read something about it only being effective for finding up to 10 to 20% if unviable cells, probably related to what your saying.

 

[felten]

Beginning to wonder if I am the only one who sees something wrong with the guy who co-authored a book with a manufacturer of liquid yeast being totally at odds with the three big manufacturers (all much bigger than Whitelabs) and their paid professional yeast experts.
Considering the scant mention of dry yeast given in Yeast: The Practical Guide to Beer Fermentation (Brewing Elements) you would be left in no doubt as to the bias of the authors.
And yet we are asked to take Jamils word for how many yeasts are in a packet and the best way to handle that yeast.
Like I said isn’t anyone just a little cynical aren’t there any faint tinkling of alarm bells in the distance?
The idea that you must rehydrate yeast – reference Chris White/Jamil
That half your yeast will die if you don’t – same/same
That you get 3-4 times as many yeast cells as the maker claims – think about it.
I guess if you use dry yeast and you follow Mr Maltys advice and don’t get the results you wanted you should have brought a liquid culture in the first place – don’t worry you will know better next time – seriously?

I both use and sell both dry and liquid cultures, both have their place but I never bother with Mr Malty, I really think he can’t count and I am quite capable of working out from the manufacturers cell counts how much yeast I need in a brew.
Mark

What a crock... You sound a little too much like NickJD with the conspiracy BS.

Dr. Clayton Cone, who I believe is the head of the lallemand yeast lab, has made statements about the cell count per gram, and pitching death rate that agree with what Jamil/Chris White are saying.

ref; http://koehlerbeer.com/2008/06/07/rehydrat...r-clayton-cone/

Each gram of Active Dry Yeast contains about 20 billion live yeast cells. If you slightly damage the cells, they have a remarkable ability to recover in the rich wort. If you kill 60% of the cell you still have 8 billion cells per gram that can go on to do the job at a slower rate.

ed: no offense intended Nick, or Mark

 

[Nick JD]

What a crock... You sound a little too much like NickJD with the conspiracy BS.

Comparing Mark's comments to mine is probably the biggest insult you could make to him, and the biggest compliment you could make to me. I'd think you were even cooler if you weren't from the CIA and your name wasn't a toiletpaper brand. One should never trust toiletpaper - I'm pretty sure that's how they get the probe in all of us.

 

[Batz]

It been an interesting thread with some good information being posted.

Thanks to the posters who have contributed. Lets let everyone have their say without getting personal with **** slinging hey? Believe me I get my share of this these days and I believe it's cowardly.


Now me?

I use dry yeast on occasions and I sprinkle it on the wort, works for every time for me. How many yeast cells are in there, really I don't give a Tinkers Cuss as long as it works.

I do like to learn the science behind this stuff though.

Now be nice possums

Batz

 

[MHB]

It has nothing to do with conspiracy theory, I was simply trying to highlight the circular nature of the discussion; the point that a book that purports to be the final word on yeast for home brewers basically ignores dry yeast isnt acceptable.
I suspect that more than 85%+ of home brew made is produced with dry yeast; I would have had a little more respect for Yeast if they had put in a chapter on dry yeast, even if it was a chapter on why they hate it. The expression to dam with faint praise comes to mind.

The biggest problem I have is that people are sighting Mr Malty/Jamil/The Yeast Book as the reference for almost all discussion regarding rehydrating, pitching, making starters, harvesting... most anything related to yeast (both wet and dry); yet the calculations that Mr Malty bases his work on are at best very suspect, I cant find or think of any reason why all the Dry yeast manufacturers would site Viable Cell Counts 1/3-1/4 of what Jamil reports, nor can I understand why because Jamil says it, it carries more weight than the manufacturer (sorry but that really is nonsensical).
The same type of discussion about how much dry yeast to use, when Fermentis say a packet of (e.g. US-05) is sufficient for 20-25L of wort, people disagree because Jamil says its not enough... the same guy who gives the subject of dry yeast scant attention in his book - I think you can see why I find the whole discussion somewhat bemusing.

Personally any respect I had for Jamil (and I believe he has done a lot of good work) and Chris White (again a maker of fine products that work well) has been largely eroded by the yeast book and things like demonstrating that half the cells are killed by sprinkling into a wort, when we can be fairly sure half of them were dead in the packet ok being generous, put it down to the American view that Hype is the only way to sell your message.
Personally I would like a simple clear explanation of why one choose wet or dry yeast, the relative merits of each, even a bald statement that the author has a personal preference to the treatment dry yeast has been given.

Like I said its not a conspiracy theory, a bit of indignation, a touch of disappointment and not a little contempt.
Im working my way through The Yeast in the Brewery; hard work and very challenging but a thoroughly professional approach to the subject, it just looks at what breweries do, why and the best way to get the results we are aiming for.
Mark

 

[Wolfy]

Im working my way through The Yeast in the Brewery; hard work and very challenging but a thoroughly professional approach to the subject, it just looks at what breweries do, why and the best way to get the results we are aiming for.

Looks interesting ... and expensive.

 

[MHB]

And one of those books that makes me regret not doing a lot more study when I had the chance, how does it go youth is wasted on the young.

This thread has sent me off doing a lot of other reading as many of the better threads here do, I dont want anyone to think I have anything but the highest regard for the work of Dr Cone, he is one of the world experts on yeast, there was one discussion on another forum that I thought summed it up pretty well; basically that yeast experts are very good at telling you about yeast health which is their only concern, which is a very different subject to brewing with yeast, for that you need to talk to brewers.
Mark