Top cropping US 05 how long can it go

[brew_ny]

Good Day I have a yeast question about top cropping and how long can the yeast go

I us 05 most of the time for the ales I brew and 04 from time to time

I have been top cropping a couple of packs of yeast for a very long time and will more then likely start again fresh soon

but the question is this in the end how long can I keep harvesting the same yeast without problems?

I smell my yeast before using it, if it smells like fresh yeast then it's all good ?

I ferment at 64 - 65 F and my ales all taste clean

05 is cheap but why buy what I already have


thanks

S_M

 

[rhys333]

I think you've answered your own question really. I would keep using it until you either notice a change in characteristics or get tired of it and want to try a new strain. You can follow the 5-10 cycles rule, but it sounds like you want to see how far you can push it.

Suddenly remembering the Seinfeld episode where Kramer drives a new car until it runs out of gas.

 

[giraffe]

5 cycles is certainly safe. Ive gone 8 (with different strains, not cal ale) with no issues. Besides infection, theoretically the biggest issue is you are selecting for better flocculation. After many generations flocculation may improve, which may cause attenuation to suffer.

 

[rhys333]

I haven't gone any further than 8 myself (yet) due to the chance of infection as you describe giraffe. I expect floccuation could change with a strain like US-05, though as an aside I find true top-croppers (like a number of English and German strains) tend to stick to the numbers as long as harvesting is done on the correct schedule each time.

 

[Zepth]

BRÜLOSOPHY did one of these. Experiment with 4th gen vs fresh. Highlights:
" I’ve taken yeast out as far as 15 generations without any noticeably negative impact on the finished beer"

"First off, both beers taste good, the differences are slight enough that most folks likely wouldn’t be able to tell them apart if served at different times. I personally experience a very slight vegetal-like aroma and flavor in Lloyd, which I wouldn’t have expected given it was fermented with a fresh vial of clean yeast, it seemed to take-off faster, and fermented healthily."

I wouldn't mind seeing a similar side-by-side with a 20th gen vs fresh. Don't think I'll be the one to do it though.

 

[brew_ny]

I have been using the same yeast since September of 2013

I was just trying to figure out what to look out for other then bad smell

without a microscope

https://www.wyeastlab.com/com-yeast-harvest.cfm

this is a good read, I will start a fresh in a couple of weeks and do a better job of counting

lot of times I top crop from fermenter to the other when I brew a batch a day or so apart

the beers I crop from are always around 5% abv

thanks for the replies

S_M