Top Cropping Coopers Yeast

[squirt in the turns]

Is it possible to get a decent crop of viable cells from the krausen of re-cultured Cooper's yeast?

Has anyone done this with success?

I've done some searching on this topic and found very little info. There seems to be some speculation about this yeast - that it may be a blend of 2 strains, or that it's derived from an English ale strain, but nothing definitive about top-cropping.

I understand that the risk when trying to top crop a yeast that isn't a "true top-cropper" is underpitching, even if pitching the entire krausen from one batch into another batch of equal size and gravity. This kind of leads me to a side question: what does make up the krausen of a yeast that's not a top-cropper, if not viable cells? Dead cells? Cells in an inappropriate metabolic state? Trub?

 

[Yob]

Top Cropping Search Results

 

[squirt in the turns]

Thanks Yob, but I've already read plenty of the generic info on top cropping. If I'm working with a known top-cropper like WY1469, I'll literally scoop the krausen directly from one fermenter to the other. I was hoping to get some specific advice about the Coopers yeast, to avoid risking that practice with a strain I know nothing about the top-cropping potential of.

That said, I was having a (re-)read of some of Wolfy's posts that came up in your search results link, and it did occur to me that I could crop the krausen into a jar and wait for it to settle and see what kind of volume I get (assuming sufficient volume is the primary concern when pitching harvested yeast?).

 

[Yob]

assuming sufficient volume is the primary concern when pitching harvested yeast?

as with any pitch, various factors affect the required amount of yeast you need to pitch. primarily gravity and volume (Ale or Lager) and temperature of the proposed ferment as well.

When collecting yeast, by rinsing or top cropping (Mostly rinsing for me TBH but I do occasionally top crop), I always like to collect about 100ml (settled) in a jar, this allows me to then tailor the pitch to the next brew.. ie if I work out I need 65ml of yeast its easy to pitch the required 195-200ml from 300 total liquid volume in the graduated jar.

Others do less and report good results.

Below are a couple of captures from Mr Malty, changing only the viability from 100% (top cropped direct re-pitching) to 90% (Rinsed Slurry 1 week old) has changed the pitch from 65ml to 72ml, not an insignificant amount.



:icon_cheers:

 

[Fourstar]

as with any pitch, various factors affect the required amount of yeast you need to pitch. primarily gravity and volume (Ale or Lager) and temperature of the proposed ferment as well.
When collecting yeast, by rinsing or top cropping (Mostly rinsing for me TBH but I do occasionally top crop), I always like to collect about 100ml (settled) in a jar, this allows me to then tailor the pitch to the next brew.. ie if I work out I need 65ml of yeast its easy to pitch the required 195-200ml from 300 total liquid volume in the graduated jar.
Others do less and report good results.
Below are a couple of captures from Mr Malty, changing only the viability from 100% (top cropped direct re-pitching) to 90% (Rinsed Slurry 1 week old) has changed the pitch from 65ml to 72ml, not an insignificant amount.
View attachment 59242 View attachment 59241
:icon_cheers:

One thing to note for those not rinising their trub collection is you have to take into account volume taken by protien, hop particulate etc settling. This is where Mrmalty calc comes in handy, i typically will double (or there abouts) the volume needed compared with pure cells.
The old 4.5billion cells/ml rule only applies to pure compated yeast, which is more akin to properly washed yeast or top cropping.

 

[ashley_leask]

One thing to note for those not rinising their trub collection is you have to take into account volume taken by protien, hop particulate etc settling. This is where Mrmalty calc comes in handy, i typically will double (or there abouts) the volume needed compared with pure cells.
The old 4.5billion cells/ml rule only applies to pure compated yeast, which is more akin to properly washed yeast or top cropping.

I don't think 4.5b is actually compacted, I think they mean thick liquid. In Jamil's Yeast book (p 123) they use 8b cells/ml as the solid compacted yeast at the bottom of a White Labs tube, and say that has a volume of 14 mls (versus 36ml fill level of 47ml total volume of the tube). 8x14=112 billion cells per tube.

 

[Nick JD]

I can't remember seeing a lot of yeast on top of CPA fermenting... Foam, yes, but not sludgy yeast.

 

[soundawake]

I've got a Coopers Pale esque recipe using Coopers yeast in day 3 of fermentation now... shall I take a happy snap of the krausen and post it?

 

[squirt in the turns]

I can't remember seeing a lot of yeast on top of CPA fermenting... Foam, yes, but not sludgy yeast.

I pitched on Sunday night (48 hours ago). 24 hours in it had a nice krausen, but as you say Nick, foamy, not dense and creamy. Has dropped back a bit today. I brewed a double batch (no-chilled) and was hoping to inoculate the second cube with yeast top cropped from the first.

I'll wait and harvest and rinse the yeast from the trub, and pitch it based on the advice above. Cheers all :beer:

 

[Kai]

To guarantee a good top crop from a yeast you need to see three distinct stages on the surface of the fermentation.

Stage one looks foamy and contains little to no useable yeast. This ought to appear the day after pitching as the yeast starts to do its thing, and roughly during the first third of the drop in gravity.

Stage two takes on a creamy appearance. The foam subsides, appears to thicken and you have the sticky goo that can only be described as yeasty goodness. This is when you crop. In a beer of healthy fermentation and 'ordinary' strength, this stage ought to appear 2-3 days after pitching. Specific gravity should range from half-complete to nearly done.

Stage three is when the yeast drops out and you are looking at beer. All the happy stuff is now at the bottom and you can't crop from the top. Take it from the other end instead, it's still good.

There's no hard line as to what constitutes a top-cropping yeast and what does not. There's just a varying window for time where the yeast floats on the top, ranging from seemingly forever to essentially never. You've just gotta hit that window if you wanna crop from the top.

I've never tried it with Coopers yeast but my bet is that it's definitely top-croppable.

 

[Midnight Brew]

From a recent batch I did with this yeast I had an American Amber Ale with a 1035 OG.

I pitched it late thursday night. Skimmed on Friday morning. When I got home Friday night it was all good to be cropped and thought I'd just wait until the morning. On Saturday morning the krausen had gone and missed my window. It was around 12 hours from skimming the first unusable crop to being able to crop the healthy yeast from the krausen. The window may be bigger with a 5% ale.

No worries I said, I'll just be harvesting from the bottom to save me the stuffing around of culturing up a starter again. So in she goes to cold condition and then it froze. Not looking forward to drinking some coopers longnecks again.