Why does harvested yeast need to be used quicker than a pitch you get from wyeast or white labs. I've heard you want to use harvested yeast within 2 weeks for best results and viability decreases rapidly. Why is this different than fresh yeast?
william_shakes_beer said:I regularly harvest yeast from split starters and use it up to 8 months later with no ill effects. Who told you you need to use it within 2 weeks?
Are we talking simply harvesting yeast cake, or washing yeast?
I just used month-old washed yeast, and have two more mason jars in the fridge washed and harvested from the same fermenter that I figure on using sometime in the next 5 months or so.
I've heard the 2 weeks thing as well. I believe it was from the yeast book. However, I have used 6 month old washed yeast on more than one occasion with great results.
I remember reading it from the Yeast book as well and being surprised because I have had the same results. However I think they are talking about ideal conditions and the hidden desire to sell more yeast.....
Dave
However, I have used 6 month old washed yeast on more than one occasion with great results.
Have used 4 month old yeast cake with good results.
I think like anything, a mysticism surrounds the big commercial producers that makes it seem far more magical than actuality.
I have used dried out 4 month old whole cake, no problems. Might have been overpitching, but who can say how many cells were viable?
Sanitization is part of the issue. Someone like white labs is growing their yeast from pure stocks in sterile, not just sanitized, conditions.......
indeed, my assumption in this thread is that we're talking about directly pitching saved slurry from a mason jar. make a starter and the age doesn't matter nearly as much. in matter in so far as you want to know how many cells you're starting with, so you can estimate how many you'll end with (and consequently if you need to step up).If you've made/are making a starter the age of the yeast is irrevelant- When you make a starter, and grow it, you're replicating more yeast to make up for any loss. You're making new, fresh yeast.
another very good consideration. over time the yeast will be dying out but bacteria could be growing (or at least not dying off as quickly).Sanitization is part of the issue. Someone like white labs is growing their yeast from pure stocks in sterile, not just sanitized, conditions. Consequently, there is a lower probability of contamination.
Pure stocks. from whence did these magical stocks come? and how does whitelabs keep them pure and happy?
Not saying that you are wrong, it just sounds like mysticism.
Given the cost and viability or dry yeast, maybe drying is the ultimate storage method?
Pure stocks. from whence did these magical stocks come? and how does whitelabs keep them pure and happy?
Not saying that you are wrong, it just sounds like mysticism.
Given the cost and viability or dry yeast, maybe drying is the ultimate storage method?
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