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Brews & Views Bulletin Board Service * Brews and Views Archive 2004 * Archive through December 31, 2004 * One step closer to the mystery of amazing survival rates < Previous Next >

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Fredrik
Senior Member
Username: Fredrik

Post Number: 1885
Registered: 03-2003
Posted on Saturday, December 25, 2004 - 11:45 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I posted before about really high viability 80-90% in a WY2565 smack pack that was stored 19 months in the fridge. Clearly expecting way better results than my fridge slurry experiment, I didn't expect it to be *this* good. I simply didn't believe it at first.

However I wouldn't let this pass, and I plated this slurry and the viability determinatiion as per the plating/cfu method is consistent with the methylene blue method within the measurement errors.


Wether I understand it or not, these results now indicate that the viability count I originally did is correct. Both methylene blue staining and plating give consistent results.

I find this amazing. One problem with long storage and low viability may be selection, but if you have 80-90% of the population still alive after 19 months this issue seems totally eliminated?

I am going to plate it again, to make sure I get the same results again, but I now think that the cells has really survive.

I have to say though that I find it really amazing and if the reason to this amazing survival rate could be found it would allow storing yeast in the fridge for many years without reculturing. I find this topic well worth giving some more research.

I have one idea that I will try. I suspect that rather than the medium beeing tha magic (water, beer, NaCl solution etc) yeast coming right from yeast cake may not be best suited for long term storage although viable. I believe, yeast companies do not pack the yeast coming from primary sediment of beer batches. I think the history and composition of the yeast before entering storage, is *part* of the explanation. I will do more testing on this, and if I'm right I think it should be possible for homebrewers to attain these survival rates as well if done properly.

Until I have duplicated the plating results, I keep the possibility open that I did a dilution mistake and got it wrong by an order of magnitued or something. But this is now getting really interesting...

/Fredrik
 

Fredrik
Senior Member
Username: Fredrik

Post Number: 1898
Registered: 03-2003
Posted on Tuesday, December 28, 2004 - 10:47 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

I kept this smack pack slurry in a bottle in the fridge, as I wanted to do more tests on it. From visual inspection only after some weeks I didn't get the impression that it lost much viability, but today, after 45 days, it took a proper viability reading as per the methylene blue and it has dropped from 86% to 50%, which makes good sense.

Interestingly, this is is the same ballpark as the slurry in the fridge viability drop from the fridge slurry test, which dropped from 95% to 46% in 45 days.

I think the methylene blue method is not that bad after all. The survival rate in the smack packs until opened seem indeed amazing. The next project is to try to find a method to attain similar survival rates when storing my own slurries.

Heck, if wyeast can do it, there got to be a way for homebrewers to do the same, though it may take some extra tricks and efforts. These survival rates outperforms my freezing test.

I think protection from oxygen is essential. I think I will actually test the yeast jelly idea I had.

/Fredrik
 

Pete Strunk
Junior Member
Username: Strunkale

Post Number: 82
Registered: 01-2004
Posted on Wednesday, December 29, 2004 - 12:08 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Freddy,the Cool Evil Science-test! Keep up the good work.
 

Chumley
Senior Member
Username: Chumley

Post Number: 2614
Registered: 02-2003
Posted on Wednesday, December 29, 2004 - 05:15 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

One of the reasons I still smoke weed is because I live for threads like this.
 

Ken Anderson
Advanced Member
Username: Ken75

Post Number: 563
Registered: 11-2002
Posted on Wednesday, December 29, 2004 - 01:51 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Vote for Chumley!
 

Fredrik
Senior Member
Username: Fredrik

Post Number: 1902
Registered: 03-2003
Posted on Wednesday, December 29, 2004 - 03:37 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

> One of the reasons I still smoke weed is because I live for threads like this.

I have to admit I read this three times and am still processing it's meaning. I never thought Elivs was still alive in the first place.

/Fredrik
 

Denny Conn
Senior Member
Username: Denny

Post Number: 3996
Registered: 01-2001
Posted on Wednesday, December 29, 2004 - 07:54 pm:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

"One of the reasons I still smoke weed is because I live for threads like this."..and if ya didn't, this would make ya start!
LIfe begins at 60...1.060, that is.
 

JimTanguay
Intermediate Member
Username: Pizzaman

Post Number: 337
Registered: 02-2003
Posted on Thursday, December 30, 2004 - 08:07 am:   Edit Post Delete Post View Post/Check IP    Ban Poster IP (Moderator/Admin only)

Can I use those "special hops" in my beer? Man, even I've been around too long.