Top Cropping Yeast (in pictures)

[greenxpaddy]

That's the part that makes top-cropping more an 'art' than a 'science' there is no answer I can give that is 'right' because it all depends on your yeast, wort-conditions, temperature and other factors

In order to try to introduce more science and certainty into this area I thought it would be good to start a reference log for different yeast and conditions. viewtopic.php?f=12&t=54045 Hope you think it could be helpful

[smeggedup]

hi all

great post wolfy

i top cropped for the first time the other day from a london 3 thames valley yeast 1323.

this was how it looked before cropping


i collected 2 litres from 2 fv's each with 19l in


after cropping it was placed in the fridge layers formed, i didn't throw any layers away.


2 weeks and 2 days later it looked like this

all looked fine and smelt fine
so i added 250ml of dme wort to it the night before i brewed, no reaction, no fermentation

any ideas where i went wrong ?
did i store it to long before use ?
what are the seperated layers, should any be thrown away ?

cheers

[Wolfy]

hi all
all looked fine and smelt fine
so i added 250ml of dme wort to it the night before i brewed, no reaction, no fermentation

any ideas where i went wrong ?
did i store it to long before use ?
what are the seperated layers, should any be thrown away ?

Looks like you did everything fine, the only question I have is how you stored it for those few weeks?
Freezing the yeast or keeping it too warm will likely kill many of the cells, but keep it at normal refrigerator-temps and you should be fine.

[greenxpaddy]

" so i added 250ml of dme wort to it the night before I brewed, no reaction, no fermentation "

The lag phase of 12-24hrs might not show normal (anaerobic) fermentation but the yeast would still be growing. Did you aerate the 250ml wort?

Also just thought. Did you bring the wort and stored yeast to the same temp before pitching? You can shock the yeast if you throw yeast straight from the fridge into wort at say 25c

[smeggedup]

hi all
all looked fine and smelt fine
so i added 250ml of dme wort to it the night before i brewed, no reaction, no fermentation

any ideas where i went wrong ?
did i store it to long before use ?
what are the seperated layers, should any be thrown away ?

Looks like you did everything fine, the only question I have is how you stored it for those few weeks?
Freezing the yeast or keeping it too warm will likely kill many of the cells, but keep it at normal refrigerator-temps and you should be fine.

cheers wolfy
yer it was kept it the fridge

i'll try again next brew

[beerlover36]

I've always been a top cropper, I keep it in the fridge and have successfully pitched after as long as 4 weeks. Leaving it for this long can be hit and miss though, a couple of weeks should be fine, but after that you run this risk of being left with a jar of dead yeast and a full brew of beer for the bugs to get at first.

I also crop some slurry after I've racked to a secondary, this serves as a good back-up. I've noticed that the slurry seems to stay viable longer than the top-cropped yeast, this adds weight to the theory that towards the end of fermentation the yeast readies itself for dormancy.

[Matt]

I've noticed that the slurry seems to stay viable longer than the top-cropped yeast, this adds weight to the theory that towards the end of fermentation the yeast readies itself for dormancy.

Interesting observation

[mozza]

Just throwing this out there- in the yeast book it says that if the ph of your yeast slurry/rinsed yeast rises by more than 1, then there is considerable cell death. So testing the ph will give you a good indication as to the viability of the yeast.

[6470zzy]

I had to make a blow-off-cap for it:



The bungee cord around the FV is in case the yeast decides to "make a break for it"