Reusing Yeast

[TartanSpecial]

this will be the first time, but I've emptied it from the bottom valve before so I know what to expect...can;t remember if saf05 goes solid or remains a liquid slurry..

 

[Smileyr8]

this will be the first time, but I've emptied it from the bottom valve before so I know what to expect...can;t remember if saf05 goes solid or remains a liquid slurry..

I have repitched from Saf 05 & it remains fairly liquid.

 

[TartanSpecial]

First saf05 successfully harvested.....will find out when I pitch it into another brew in a couple of weeks.

 

[rodabod]

That Fullers / Wyeast 1968 was difficult to bottle! Had to water it down as it was so solid. Now have about three litres of slurry in the fridge.

 

[Padawanrob]

Hi, Im experimenting with yeast harvesting and I basically get 8.5ltrs of AG beer after my small batch brew, I was wondering if there was anyway I can calculate how much harvested yeast I need to pitch in a small batch, I usually go for 6g of dried yeast but this will be my 1st time with a harvested yeast.

cheers in advance

 

[mike77]

I recently did a similar size batch and I put 4 teaspoons of slurry that I had collected about 3 weeks earlier. There was fermentation activity within a few hours so I suspect it was over pitched slightly although I don't think that is a worry.

 

[YeastFace]

I believe the Mr Malty calculator advises the quantity of slurry to pitch, but you need to know yeast concentration and how much of the slurry is trub, hop debris etc.

The Brewer's Friend one is less complicated, but I've no idea on its accuracy - http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

 

[Padawanrob]

I believe the Mr Malty calculator advises the quantity of slurry to pitch, but you need to know yeast concentration and how much of the slurry is trub, hop debris etc.

The Brewer's Friend one is less complicated, but I've no idea on its accuracy - http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

as Im new to this how do i calculate the the yeast qty from the harvested yeast without having any scientific equipment, is the slurry density the amount of yeast compared to trub in the final harvest, I have 2 x 500ml jars with the washed yeast in my fridge but no way of me knowing the density, is there a simple way of me doing this or should I just go with around 3 teaspoons and experiment?

sorry for all the questions

 

[Padawanrob]

as Im new to this how do i calculate the the yeast qty from the harvested yeast without having any scientific equipment, is the slurry density the amount of yeast compared to trub in the final harvest, I have 2 x 500ml jars with the washed yeast in my fridge but no way of me knowing the density, is there a simple way of me doing this or should I just go with around 3 teaspoons and experiment?

sorry for all the questions

this is a pic as it is still settling out, i can see the yeast starting to settle on the trub but I wouldn't know how to calculate the %

 

[MyQul]

as Im new to this how do i calculate the the yeast qty from the harvested yeast without having any scientific equipment, is the slurry density the amount of yeast compared to trub in the final harvest, I have 2 x 500ml jars with the washed yeast in my fridge but no way of me knowing the density, is there a simple way of me doing this or should I just go with around 3 teaspoons and experiment?

sorry for all the questions

When all the yeast is settled out and compacted down to as much as it's going to, it will be 1.2billion cells per ml. You can measure how much you've got by getting an identical jar to the one you've got it in and filling it up with water to the same level of your yeast then measuring how much water you've got.

It's quite hard to tell from your piccy but it looks like you've got a distict trub layer at the bottom. You'll need to subract that from your calculations

 

[JapanBrew]

Sorry to re hash this thread but everyone is saying rinse with water others say not ( I lean on the not using 1/10 DME ) but couldn't you do both? Start with a water rinse to remove old beer residue. Settle it out for couple of hours. Dump off the top, re agitate, let sit so trub settles. Make a 1.020 DME mix and then pitch and let the yeast ferment for a few days, agitating it 2 or 3 times a day.
From there, no more water rinse. Just keep splitting it from there. Would this be a bad thing?

 

[Hoddy]

Buy the yeast elements book by Chris white (white labs) it has everything you need to know about collecting, cleaning, storing and re pitching yeast and starters.

 

[Hoppyland]

Have a look at this article about an experiment done where experimenter both over and under pitches yeast, along with a control 'correct amount'

http://sciencebrewer.com/2012/03/02/pitching-rate-experiment-part-deux-results/

Interesting article - I'd never thought much about under or over-pitching before.
Mind you, I'm cautious about the conclusions. They may be correct. However, I must say that the title of the blog - Brew Science - seems to me to rather overstate things. For a goodly number of reasons this "Pitching Rate Experiment" is most definitely not a well constructed scientific experiment.
Even if the conclusions happen to be correct for this particular yeast, under these particular circumstances (although these are barely specified), I would be extremely wary of extrapolating this to other yeasts, with other malt profiles and other conditions.
Don't get me wrong, I'm not knocking peoples personal experiences (mine are pretty well all I've got, and of course I use them to build upon) However, as a recently retired scientist, I'm acutely aware that my experience in brewing has been that of an artisan - gradually accumulating skills (I hope :)), and that none of my "trials" have been scientifically valid experiments at all (Too much bother!! but, seriously, only me to please, so I can drop the rigour & let my taste buds decide :thumb:)
No, what gets my goat here is the idea of this being thought of as "science", when it's really a poor imitation.
Rant over....thought: perhaps must read more about pitching rates :smile: