I remember reading the science answer to why the yeast aren't suitable for regrowing but then I have done it myself with good effect.
I think the problem is more to do with mutation so may only become apparent with multiple pitches
Harvesting yeast.
- Thread starter dweb
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I think the problem is more to do with mutation so may only become apparent with multiple pitches
brumbrew
Regular dufus
I've jut been listening to a beer smith podcast on yeast. Apparently repitching yeast is ok until the yeast begins to run out of its reserves of zinc. That's what can stress it out and cause more off flavours.
MyQul
Chairman of the Bored
It all depends how you re-harvest. Harvesting can put selective pressures on a yeast. So if you continually bottom crop you get more an more flocculent yeast cell. The effect this has is that yeast can only ferment your beer when in suspension so if a majority of your cells are on the bottom of the FV you eventually get a yeast then has a lower attenuation.
An ex-member did this with nottingham yeast as an experiment, and re-pitchedfrom slurry from the bottom of the FV (iirc) 11 or 12 times before he noticed a difference in attenuation
Top cropping is different and you can harvest (possibly/probably) infinitely as your harvesting a mix of all types of cells.
Overbuilding a starter then portioning of a bit to use in the next starter is another harvesting method which you can re-use many (and I've read, again, possibly infinately) times as the yeast is re-grown and re-charged (vitality and viability) each time in the new starter
When I can I get to a local brewery for yeast.The head brewer has told me they have used the same yeast since the early 1970's, no washing or rinsing just top crop and re-pitch within a few days. They took the yeast from another local brewer who had done the same for as long as anyone can remember. I'm sure I have been told or read the reason it does not work as well with dried yeast is drying weakens the cell walls. This can cause mutations why I don't know but it does seem harder to keep going. With most live yeast as long as it's kept well it can be used a lot longer although like my wife some strains are temperamental. Also avoid duel strains as one will overpower the other.
Sadfield
Landlord.
I'm not sure that is entirely true. There appears to plenty of evidence of breweries having their yeast analysed and found to be multi-strain. Harvey's for example.
Commercial blends containing combinations of Saccharomyces, Brettanomyces and Bacteria tend to carry this advice due to differing growth rates and tolerance to hops or acidity. However, I don't think that necessarily extrapolates to mixed Saccharomyces blends.
There's an arguement for, the older the yeast, the less likely any lab work to isolate one specific strain was done.
Whitelabs appear to condone multiple strains https://www.google.co.uk/url?sa=t&s...FjABegQIBxAB&usg=AOvVaw34Sw0dJSP8PlolYWXzNMb3
"Even though proportions of strains are changing generation to generation, there’s typically enough cells to still perform similarly"
One would suspect your breweries 30 year old yeast is multiple strains that have hit an equilibrium.
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I can only go by my own experience with Adnams yeast from a mini keg. Only went two more generations.
The Adnams dual strain seems to be unequally matched with one of them overpowering the other after a few reuses. They document it on their site. Interesting stuff.
Sadfield
Landlord.
Yet they continue to use a dual strain. So not something to be avoided, but may require some management to maintain in some instances.
Interestingly, I've just checked, Jeff Alworth's book The Secrets of Master Brewers: Techniques, Traditions, and Homebrew Recipes, and it's Adnams that recommends pitching more than one yeast, and hints to looking at Belgian yeasts. They use one flocculent strain and one that isn't.
Interestingly, I've just checked, Jeff Alworth's book The Secrets of Master Brewers: Techniques, Traditions, and Homebrew Recipes, and it's Adnams that recommends pitching more than one yeast, and hints to looking at Belgian yeasts. They use one flocculent strain and one that isn't.
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Smileyr8
Impressive Member
I have been using WYeast Activator 1469-PC West Yorkshire Ale Yeast, as my house yeast since October 2016, it has been through at leaat 15 brews (Pales, Goldens, Bitters & Stouts) its probably not true to the original strain but its still doing a great job.
MyQul
Chairman of the Bored
That's very interesting, Sadfield. Ive been using the Gales strain on and off for the past few months. I might capture another strain and mix it with the Gales to see what happens
MyQul
Chairman of the Bored
I was aware you have been using 1469 from some of your posts. How do you store your top croppings as I was given to understand you need to use top cropped yeast straight away, or at least within a couple of days
Smileyr8
Impressive Member
I usually crop it into a large screw top jar then store it under an inch or so of one of my current brews (I keg all my beer nowadays) then store it in the kegerator ready for my next brew (3-6 weeks), when I am ready to use I make up a starter using DME while my brew is mashing, some times it kicks off and goes crazy within 30 minutes (3 weeks) and sometimes it only shows signs slight signs of activity shortly before I pitch it (6 weeks).
MyQul
Chairman of the Bored
There's a photo floating around the forum somewhere of a forumite having put some top croppings (think its the wye valley brewery strain) in a small amount of starter. The photo is taken a few minutes after doing this and the yeast is crawling out of the jar as if it's trying to take over the world
