Advice about pitching onto a yeast cake please...

[crashlann]

I hear Jamil and many other respected brewing elders refer to pitching new wort onto a yeast cake of a beer that just fermented. I understand about the risk of dead yeast, and potential off flavors...but if people are doing it and having good results, it must be doable. Who does this and what advice do you have? I do not plan on doing this very often, but Im fermenting a Saison right now and I want to move it to secondary and add Brett. After I move it, I want to add another Saison wort and experiment fermenting that at higher temps. I also plan on harvesting 50ml of the yeast for another starter. I do not plan on pitching onto a yeast cake more than once per beer. Any ideas, experience or words of wisdom? Thx.

[Effingbeer]

Do it.
Works great. Leave room for an extra vigorous fermentation.
No problems thus far.

[ultravista]

I pitched on an existing yeast cake for the first time last Sunday (Raison D'Etre clone). Fermentation took off quick, within 15-20 minutes.

Time will tell how it turns out.

Preliminary taste, albeit young, are promising.

[PorkSlapper]

Floating around this forum is a super simple way to wash yeast from a previous fermentation. This will help get rid of any trub, and dead yeast.

[Afterlab]

For a powdery yeast like a Saison strain if you use the yeast in the trub you're only getting the yeast the flocs out the quickest. Part of me thinks you need to carry over a decent percentage of the yeast that doesn't flocculate out otherwise you're going to likely end up with an under-attenuated beer for the second generation. I think the yeast cake method is fine (not ideal IMO) when using a strain that flocs out well but not the best with powdery yeast strains.

My only concerns would be losing a decent amount of space in a carboy from the trub pile (obviously not a huge deal), having such a large amount of yeast cells that strip out isomerized alpha acids and a lack of nutrients for such a large population of yeast cells.

[crashlann]

For a powdery yeast like a Saison strain if you use the yeast in the trub you're only getting the yeast the flocs out the quickest. Part of me thinks you need to carry over a decent percentage of the yeast that doesn't flocculate out otherwise you're going to likely end up with an under-attenuated beer for the second generation. I think the yeast cake method is fine (not ideal IMO) when using a strain that flocs out well but not the best with powdery yeast strains.

My only concerns would be losing a decent amount of space in a carboy from the trub pile (obviously not a huge deal), having such a large amount of yeast cells that strip out isomerized alpha acids and a lack of nutrients for such a large population of yeast cells.

Thanks. Why does this practice work for commercial breweries that pull yeast out of the conical. Isnt that the yeast that floccs early, or do they remove the early yeast, crash cool it to get the yeast remaining in suspension out and then use that yeast?

I know its not the best technique (dont sweat the technique...) but I hear people talking about doing it so I thought to maybe give it a try. Maybe I will go ahead and wash some like usual...Thx!!

[Afterlab]

Why does this practice work for commercial breweries that pull yeast out of the conical. Isnt that the yeast that floccs early, or do they remove the early yeast, crash cool it to get the yeast remaining in suspension out and then use that yeast?

I know its not the best technique (dont sweat the technique...) but I hear people talking about doing it so I thought to maybe give it a try. Maybe I will go ahead and wash some like usual...Thx!!

As unromantic as it sounds, the majority of brewpubs and breweries use the most reliable, predictable, flexible, easy to work with and flocculant yeast they can for the majority of their beers. Chances are they don't have to mess with finicky yeast strains for their year-round beers. That's why Cal Ale, ESB and a lot of English strains are popular.

If they're pulling out of the conical chances are they're are or should be doing some sort of rinsing, acid washing and sensory and microscopic analysis to ensure they're propagating a fairly young collection of yeast cells with very few bud scars. Breweries that want to stay in business know they need to deliver a consistent product and that can only be done with consistent and predictable ingredients--more so yeast than anything. Breweries are also transferring a lot less hot and cold break into fermentation which helps alleviate a number of issues for product and yeast stability.

[brewinhard]

At breweries they let the yeast drop into the conicals and typically will only collect the healthy, middle section of creamy white yeast and discard the trub and dead yeast cells from top and bottom sections.
If you want to use the yeast cake after racking over you might want to consider simply dumping out some of the cake first (if you aren't up for rinsing it) before racking the next beer on top as you will not need that much yeast/trub going into your next beer even if it is a moderately strong saison.