Many here keep stating that you can only wash yeast and use it a maximum of five time or risk getting off flavors and mutated yeast but i just finished watching a documentary on the Budweiser factory and one of the master brewers stated that their yeast strand are of the original yeast . What led me to believe that they.harvest and care for their yeast for years and years... Now to my question.... Why do some here state that to only use it 5 times? Or is.it that someone who worked at a yeast distributor started the myth to ensure people kept buying ?
Harvesting yeast question
- Thread starter Big_Cat
- Start date
Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:
you're talking about 2 different things.
when homebrewers wash yeast, they are re-using the same cells.
the commercial breweries use yeast banks. they "bank" the original strain, freeze it, and propagate from that. they do re-use the same batch of yeast, but after a few generations they will dump it and go back to the original source and get a refresh. it's a little more complicated than that, but that's the general idea - they go back to the source. as Ben58 mentioned, having dedicated labs techs (or a yeast management company) makes this a lot easier.
when homebrewers wash yeast, they are re-using the same cells.
the commercial breweries use yeast banks. they "bank" the original strain, freeze it, and propagate from that. they do re-use the same batch of yeast, but after a few generations they will dump it and go back to the original source and get a refresh. it's a little more complicated than that, but that's the general idea - they go back to the source. as Ben58 mentioned, having dedicated labs techs (or a yeast management company) makes this a lot easier.
+1^^^
They probably have a staff/facility/budget just for "yeast" that exceeds the ENTIRE facility/staff/budget of any microbrewery in America. . . . . .
Much less homebrewer.
They probably have a staff/facility/budget just for "yeast" that exceeds the ENTIRE facility/staff/budget of any microbrewery in America. . . . . .
Much less homebrewer.
AgentHubcap
Well-Known Member
Yes, you can, but you probably won't know when it starts to mutate on you. I know some people on here go much farther than 5 times. I normally go 3 times (or so).
Big_Cat said:
Make a streak plate of whatever strain you want, then go back to that to start a new culture after every five or so batches. That's what I understand they do in industry for house strains.
When I get a new yeast strain I make a starter that is larger than needed. I then make 4 vials from that with 5ml yeast, 5ml glycerin and 10ml water. I freeze these. If I were to make 4 more each time I used it for 4 generations I could make 256 brews from the original vial. Since I brew maybe twice a month and use many different yeasts it is doubtful that I will use any single yeast 256 times. I have 8 different strains in my yeast bank so far.
thrstyunderwater
Well-Known Member
Do you care to post anymore on this or can you point me to another source? I'd love to be freezing yeast but haven't ever found a source on how to properly use the glycerin.
I'm interested as well...yeast washing..harvesting ..freezing ...all comes down to savings and i love to save money
dpark
Member
dinnerstick
Well-Known Member
mutations in a yeast strain are only bad if they make your beer bad. genetic mutations can occur randomly by small changes to the DNA, but the whole population of cells can't suddenly mutate. but it's very true that the behavior of the population can change over only a few yeast generations. harvest just the last dusty bit of yeast to flocculate, and repitch that, you'll get a very different result than you expect from that strain. these behavioral changes are likely 'epigenetic', rather than due to DNA mutations; genes stay the same but get locked into certain on/off states, and it's these states that can confer certain properties, like willingness to flocculate, ability to consume maltotriose, whatever. but one random mutation in a population of hundreds of billions of cells cannot propagate rapidly through the population over the course of a few brews, with each brew hosting fewer than 10 yeast generations, even if you select for it. if you keep harvesting healthy clean yeast and your beer keeps being good, and the yeast behaves the way you want it to, keep using it. not that you shouldn't save a master stock if you can, and propagate new pitches from that whenever needed; it's a luxury but it's nice to have a few strains banked, and you will need to go back to the master stock eventually. remember it will take longer to get them up to a pitchable amount than a new smack pack, and you should work very cleanly at the early steps to avoid propagating contaminants.
Similar threads
Latest posts
-
Why didn't anyone ever tell me to buy a grain mill sooner- Latest: corkybstewart
-
-
-
-
-
