Perpetual Yeast method.

stormtracker · 03-29-2008, 07:50 PM

Reading many posts here it seems that a technique being used is to utilize the yeast in the trub at the bottom of each primary after fermenting out and racking.

So it got me to thinking. Can I just take the used trub from the bottom of a fermenter and just pour it onto my next freshly brewed wort?

Am I to understand that the yeast is still good and will continue over a long period of time to be good? Can I re use it over and over again or is there a time it starts to peter out? Say every few batches or so?

One concern would be that somehow the wort before became contaminated and I keep inoculating over and over again several worts before I discover the issue.

Does anyone use this method? If not why?

Any thoughts or ideas?

**Revvy** · 03-29-2008, 07:52 PM

a lot of people do it....I've done it on occasion...

actually you don't pour the trub into the wort...you rack the wort onto the trub in the bottom of the fermenter.

2 things to remember...(1) you should always go darker on what you pitch onto...you don't want to brew a pale ale on top of an stouts yeast cake...unless you want some of the flavors of the previous batch to be tasted in this one..

(2) Use a blowoff tube!

stormtracker · 03-29-2008, 07:58 PM

I read that as well.. Pour the wort on the old trub. Im being anal though as the Belgians I brew leave lots of crap behind in the fermenter (carboy).

Would this mean I shouldn't worry about it and I should never have to clean a primary fermenter carboy again?

**Revvy** · 03-29-2008, 08:03 PM

Quote:

Originally Posted by stormtracker

I read that as well.. Pour the wort on the old trub. Im being anal though as the Belgians I brew leave lots of crap behind in the fermenter (carboy).

Would this mean I shouldn't worry about it and I should never have to clean a primary fermenter carboy again?

No....eventually the yeast would be too overtaxed, and full of off flavors...usually people do it no more than 4 times....If you want to do the perpetual yeast thing, you should wash it on occasion and make up starters, and clone it....Papazian has had a strain going for over 25 years....

He talks about it in this basic brewing podcast.

http://media.libsyn.com/media/basicbrewing/bbr02-14-08history.mp3

**TimBrewz** · 03-29-2008, 08:03 PM

I pitch on previous batches often just like Revvy says go from light to dark and low to high hops and it works great- about 3 times is all I re-use a yeast cake as I think it can give off flavors after a few batches. Be aware of very fast and active starts! Blowoff hose for sure.

Of course you can just take the yeast out of the carboy and wash it and repitch it later. Lots about that on this board.

Happy Brewing!

**Yuri_Rage** · 03-29-2008, 08:07 PM

There are ways to make it more perpetual, but if all you're doing is dumping one batch on top of the yeast cake from the previous batch, 3's the generally accepted limit.

If you want to make sure that you have the same strain of yeast for lots of batches, you'll need to look into some minor lab equipment and read up on yeast propagation. Some breweries are able to culture the same yeast strain for many, many years using agar, slants, stir plates, and starters.

stormtracker · 03-29-2008, 09:16 PM

Great advice here.. Thanks guys.