Pitching Harvested Yeast - How Much Is Too Much?

[BobtheBrewer]

I know that I am going to get flamed for harvesting yeast, but I do it so here goes. My last 6 - 8 brews have had a really healthy yeast cake. If I dry hop I do so in a hop sock, so no hops in the yeast cake. I drain off all the beer, pour in 500ml of boiled water, swirl it all around, and fill up a couple of pet bottles. I wash the yeast but still end up with about 300 ml of yeast. I am a BIABer so I no chill. When I pour a no chill cube into a fermenting vessel (max 23 litres) my routine for pitching yeast is:
empty the liquor out of the yeast container, fill it with wort left over from filling the cube, give it a shake and pour it into the fermenter. This has worked for me for a long time but the last two efforts have seen the gladwrap (sorry, now cling wrap, the yanks are infiltrating us) blow up to a size where I thought it would burst. The krausen has risen to a level above the rim of the fermenter. I have 27 litre fermenters (or so I believe, they may be 25 litre). My latest effort has the dome of clingwrap 3 inches (7.5cm) above the rim of the fermenter. I figure that I must be using too much yeast and that I should harvest much less into each pet bottle in future. This is happening with dry US-05 and Wyeast 1272. Any comments?
PS. I am up to 4th generation with US_05.

 

[jbumpstead]

I know that I am going to get flamed for harvesting yeast, but I do it so here goes. My last 6 - 8 brews have had a really healthy yeast cake. If I dry hop I do so in a hop sock, so no hops in the yeast cake. I drain off all the beer, pour in 500ml of boiled water, swirl it all around, and fill up a couple of pet bottles. I wash the yeast but still end up with about 300 ml of yeast. I am a BIABer so I no chill. When I pour a no chill cube into a fermenting vessel (max 23 litres) my routine for pitching yeast is:
empty the liquor out of the yeast container, fill it with wort left over from filling the cube, give it a shake and pour it into the fermenter. This has worked for me for a long time but the last two efforts have seen the gladwrap (sorry, now cling wrap, the yanks are infiltrating us) blow up to a size where I thought it would burst. The krausen has risen to a level above the rim of the fermenter. I have 27 litre fermenters (or so I believe, they may be 25 litre). My latest effort has the dome of clingwrap 3 inches (7.5cm) above the rim of the fermenter. I figure that I must be using too much yeast and that I should harvest much less into each pet bottle in future. This is happening with dry US-05 and Wyeast 1272. Any comments?
PS. I am up to 4th generation with US_05.

The mrmalty calculator here has an option for using slurry when determining how much to pitch.

Cheers,

Justin.

 

[mwd]

I do the same but collect the yeast in 430ml screwtop glass jars ( ex black olives from Coles) I probably pitch about 250ml-300ml of slurry no problems. I think overpitching is preferable to underpitching. Never bothered looking at Mr malty for the proper amounts and I do tend to ditch it after about 4 regenerations.

I don't think you will get flamed as many people use slurry at least I think they do seems a waste not to.

 

[BobtheBrewer]

I do the same but collect the yeast in 430ml screwtop glass jars ( ex black olives from Coles) I probably pitch about 250ml-300ml of slurry no problems. I think overpitching is preferable to underpitching. Never bothered looking at Mr malty for the proper amounts and I do tend to ditch it after about 4 regenerations.

I don't think you will get flamed as many people use slurry at least I think they do seems a waste not to.

I've had a PM before about the negatives of yeast harvesting.

 

[felten]

I let my harvested and washed yeast settle out completely in the fridge, takes a day or two, and then measure the compacted slurry. Putting both sliders at the thickest yeast and highest non yeast %, it usually ends up being 60-80ml (80-140 if I use the default settings) of slurry per 21L batch.

I'm not sure if that's the correct settings for settled yeast, but I think the default settings are for freshly washed yeast.

 

[BobtheBrewer]

I let my harvested and washed yeast settle out completely in the fridge, takes a day or two, and then measure the compacted slurry. Putting both sliders at the thickest yeast and highest non yeast %, it usually ends up being 60-80ml (80-140 if I use the default settings) of slurry per 21L batch.

I'm not sure if that's the correct settings for settled yeast, but I think the default settings are for freshly washed yeast.

Thanks Felten, but I have no idea what you are talking about.

 

[felten]

The mrmalty calculator here has an option for using slurry when determining how much to pitch.

Cheers,

Justin.

^ that

Sorry should have specified what I was talking about.

 

[potof4x]

Thanks Felten, but I have no idea what you are talking about.

my idea of too much would be when my beer starts tasting bad. what you describe sounds like a good ferment; so run with it I reckon?

 

[Wolfy]

As long as the previous beer fermented without problems or infection and you are careful with your sanitation and procedures, if anyone says negative things about harvesting and re-using yeast, tell them to read the 'Yeast' book by C. White and J. Zainasheff. In the book, they actually seem to promote re-using yeast and suggest that the yeast may not perform at its best until it is repitched 2 to 3 times.

In terms of how much to use, it depends on two main factors; how much trub and debris is mixed in with the yeast, and how much non-yeast liquid is in the mix.

If you have washed the yeast there should be very little non-yeast material, and I usually measure the yeast-slurry as the amount left after the liquid is decanted, so that the slurry is only just thick enough to pour. Under these conditions - if the yeast is fresh and healthy - about 40-50ml of the 'thick pure yeast slurry' should contain about 100billion cells - or the same as a pack of store-brought yeast - so about 60-100ml is good for a single batch of standard gravity ale.