harvestjng yeast, easiest and most productive ?

[loady]

I just paid £3.50 for some yeast from my lhbs, I know I can buy it cheaper online buy I like till support the local guy. what's the best way of growing my own yeast, I am not using liquid yeasts yet, I am using dried yeast, not sure if it's best to grow the dried yeast and keep using that or use the slurry.. what's the process and how many times can you regenerate it ?

 

[MacKiwi]

I've just been rinsing and reusing the yeast-cake from the bottom of the fermenting bucket (originally from dried US05). It's been working great! I just keep it in a glass jar in the fridge until it's needed.

edit : for the process, just do a searching on "yeast rinsing". Lots of how-to guides out there. Note that it is quite different from "yeast washing"...

I don't know how many times you can do it - I haven't had any problems and I'm onto the 4th fermentation. I had a chat to a commerical brewer and he's been re-pitching the same yeast strain for years...

 

[loady]

so what, just scoop all that slurry into a sterile bottle and refrigerate ?.... sounds way to easy but I like that

 

[RobWalker]

I've just been rinsing and reusing the yeast-cake from the bottom of the fermenting bucket (originally from dried US05). It's been working great! I just keep it in a glass jar in the fridge until it's needed.

edit : for the process, just do a searching on "yeast rinsing". Lots of how-to guides out there. Note that it is quite different from "yeast washing"...

I don't know how many times you can do it - I haven't had any problems and I'm onto the 4th fermentation. I had a chat to a commerical brewer and he's been re-pitching the same yeast strain for years...

some home brewers say it'll start to mutate after 6 uses, so you may get somewhat different flavours, but i don't think it's ever going to go particularly badly. just be careful if you ever use it to brew a stout, or anything with a pungent flavour (american IPA for example) - some colour or flavour may transfer over. :thumb:

 

[Dack]

just be careful if you ever use it to brew a stout, or anything with a pungent flavour (american IPA for example) - some colour or flavour may transfer over. :thumb:

And try to keep the ABV of each re-pitched brew about the same, if you're aiming for a long term use. A good rule of thumb is to never go from high to low, only low to high.

 

[Smiddylad]

It depends how you harvest it. Top cropping is the best way as you get the most viable yeast at high krausen. If you harvest your yeast this way there is no real limit to how many times you can repitch it. Ironically the worst method for re-using yeast is a conical fermentor as the shape of the fermentor and the density of the yeast, puts the under stress. Hence the limit on the number times you can repitch. It is however the easiest way to harvest the yeast. In most cases people usually harvest the slurry at the bottom of the fermentor after bottling. The are numerous ways to do this, and the Internet is awash with them. I like to wash the yeast and store it in test tubes and build a starter as usual when I want to brew. As a back up I always keep a sachet of fresh yeast in the fridge. As I always taste my starters for infections as harvesting always runs the risk of wild yeast getting in there.

Neil

 

[loady]

hmm..cant seem to see a difference between washing and rinsing..also i have used my first ever saf05 yeast..very different fermentation from what i can see...doesnt seem to have a krausen but a really thick carpet like layer all over the top

 

[daveb]

It depends how you harvest it. Top cropping is the best way as you get the most viable yeast at high krausen. If you harvest your yeast this way there is no real limit to how many times you can repitch it.
Neil

This isnt always true....though you will get very active yeast, taking it from the top all the time will eventually change some attributes of the original yeasts...

Especially alcohol tolerance for example....if you took the yeast off the first krausen EVERY time then over a short period those yeast cells will eventually loose their original tolerance to high alcohol concentrations...

Natural selection or evolution applies to everything that reproduces..whether its sexual or asexual....any organisms attributes are moulded and shaped by external pressures of the environments they live in...

High alcohol yeasts were originally developed by subjecting yeasts to higher and higher alcohol levels during fermentation and selecting those cells that are still alive after a certain alcohol level had been reached....any dead yeast cells found will be ignored and discarded...

This process is repeated all the time brewing to higher levels of alcohol...until the yeast that live under the very highest levels are cropped and cultivated....these are then designated high alcohol tolerant.

It is an ongoing process to keep such yeast strains high alcohol tolerant and just because a certain strain of yeast says high alcohol tolerant does not mean it will stay that way over successive generations (brews)...taking yeast from the top of the very first krausen means that those yeast cells have never experienced high alcohol levels and so over a time they will eventually LOOSE their original inherited ability to withstand it!

The same situation is found can be found in bacteria and antibiotic resistance...only this is due to bacteria surviving after a small dose of anti-biotics is administered and rapidly developing genetic mutation resistance....

If you want to maintain the high alcohol tolerance of ale yeast then i would advise against top cropping!....you may be ok for a few brews but the yeast will eventually loose its alcohol resistance.....i suggest taking any yeast for cropping purposes AFTER fermentation is fully complete...any viable yeast still alive then even though stressed, will soon recover in fresh wort and still have its high alcohol tolerance attributes intact!

Yeast strains can be cultivated to adopt to various temps, alcohol tolerance and fermenting abilities its all very scientific nowadays....its always an ongoing battle to keep certain attributes intact...