Reusing recovered yeast.

[mitchmalt]

I recovered yeast from a Morland Hens Tooth a while ago, and have used it in 6 brews so far, always recovering from bottles of the previous brew, and using a starter. Is there a limit to the amount of times I do this? Today I recovered from the yeast cake and put in the fridge for a brew next week. Is this a better option or does it not matter? Thanks and apologies if already covered.

 

[Mrobson]

Google ‘acid washing yeast’

Some commercial breweries acid wash every fourth pitch and have had the same yeast for years and years :-)

 

[MyQul]

You can keep going until you notice 'effects'. A previous forumite did this with notty as an experiment and it wasnt until he hit generaton 10 till he saw the yeast become very flocculant and not attenuating properly.

What happens when you recover from your own bottles/yeast cake, is your always selecting the most floculant cells (essentially selctive 'breeding') so eventually the cells you've selected floc out so fast they stop fermenting the wort as fully

If you're happy with 10 or so gens before having to culture up from another bottle that's fine. But there is a technique called 'yeast scavenging' thats a bit like top cropping that potentially could be infinate. If you interested I'll detail the tech

 

[mitchmalt]

You can keep going until you notice 'effects'. A previous forumite did this with notty as an experiment and it wasnt until he hit generaton 10 till he saw the yeast become very flocculant and not attenuating properly.

What happens when you recover from your own bottles/yeast cake, is your always selecting the most floculant cells (essentially selctive 'breeding') so eventually the cells you've selected floc out so fast they stop fermenting the wort as fully

If you're happy with 10 or so gens before having to culture up from another bottle that's fine. But there is a technique called 'yeast scavenging' thats a bit like top cropping that potentially could be infinate. If you interested I'll detail the tech

Thanks a lot for the detail, I think I had read previously about accidentally selecting flocculant cells, but it’s really interesting about the previous forumite, thanks for sharing. To be honest the recycling of yeast was one of those experiments I just couldn’t stop, I liked the taste, don’t even know the strain!
I have wondered about top cropping, but have been put off thinking my interfering with the beer in FV could cause infection, I generally airlock and leave for 3 weeks before even opening. I am really interested in the yeast scavenging though, always keen to skill up, I’m still a newbie at AG17.
Thanks for taking the time to reply.

 

[MyQul]

Thanks a lot for the detail, I think I had read previously about accidentally selecting flocculant cells, but it’s really interesting about the previous forumite, thanks for sharing. To be honest the recycling of yeast was one of those experiments I just couldn’t stop, I liked the taste, don’t even know the strain!
I have wondered about top cropping, but have been put off thinking my interfering with the beer in FV could cause infection, I generally airlock and leave for 3 weeks before even opening. I am really interested in the yeast scavenging though, always keen to skill up, I’m still a newbie at AG17.
Thanks for taking the time to reply.

I've never used an airlock and just cover my FV with cling film. For yeast skavenging (cant claim the technique as I read about it on jims), about 36 hours after pitching you want to remove some wort from just below the krausen and fill a bottle with it. Cover the bottle with some sanitsed foil and let it ferment out. You'll get about 1/2 cm - 1cm of yeast in the bottom of the bottle when it settles out.
Then when you come to use it just pour off the beer (and drink it) and swirl up the dregs and pour into a starter.
To fill the bottle, I use a turkey baster (also as I only make 10L batches I just use a 250ml pop bottle rather than a full 500ml beer bottle) Because I cover my FV's with clingfilm, I'm able to fold back the cling film just enough to slip the turkey baster into the FV, thus minimising any infection risk. You could just push back the FV lid in a similar manner, leaving just enough room to slip the TB into the FV
Similarly to top cropping this method will get a mix of cells so potentially like top cropping you could use it from brew to brew forever. It also has the advantage of you can do it on any strain not just the strains with large krausens, like you need with top cropping

 

[mitchmalt]

Turkey baster it is then, I might even get one in the sales! Again, many thanks.