Help Defining Yeast Rinsing Layers, British 1098

Hey everybody, very insightful forum, keep up the good work! It has taught me more than I ever could have imagined Id know about beer. Thank you!

I had a quick question regarding yeast rinsing/washing and correctly identifying the different layers in the settled slurry after directly racking from the primary into a 64 oz growler. The strain in 1098.

It was my understanding that the heavier trub and debris would settle to the bottom. Counting from top to bottom, 1-4, it seems there is a very faint layer of trub at the very bottom, 4, as well as layer 2. Is layer 1 beer/water and layer 3 healthy yeast?

Thanks much.

I'm not sure but I think you let it settle too long. Most people stir up the slurry and then let it sit at room temp for roughly 30 minutes, then pour off the slurry into another jar. Doing this, the trub/dead yeast/hop matter will settle, and everything left in suspension will be good yeast!

I suspect your yeast flocculated and fell out of suspension quicker than the proteins. Have not had experience with 1098 but it seems it is only medium flocculator. You could rewash the yeast or pour of the darker layer but I suspect there is a lot of yeast in that darker layer also that you may be dumping. Have not seen it quite as pronounced as your pic.

Cell counts I gave done on three different strains and fermentation tests indicate that all layers have the same viability. Cell counts are here:
http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html

Later this month I'll post the fermentation observations. They seem to indicate that even during active fermentation the suspended cells have the same mix of live and dead cells as the slurry on the bottom of the vessel.

el_caro said:

I suspect there is a lot of yeast in that darker layer also that you may be dumping.

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I agree 100% with this part. IME the amount of protein trub is also very similar between the layers. By dumping the layer that is darker you might be removing slightly more protein than the other layer. Under the microscope it looks like a 10%-20% difference in protein content at most.

Yep--I say, swirl it up, wait 20 minutes, pour off the top layer. That's your yeast. The rest is probably OK too, but you'll get the cleaner stuff that way, and most of the nasties will have settled out.

Antler said:

... stir up the slurry and then let it sit at room temp for roughly 30 minutes, then pour off the slurry into another jar. Doing this, the trub/dead yeast/hop matter will settle, and everything left in suspension will be good yeast!

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Has any one done cell counts to verify this? It's a common statement I hear, but my experience is that there is an even mix of live and dead cells between the layers. At one point Wyeast promoted this technique, but it seems they have removed it from their site.

jerrodm said:

The rest is probably OK too, but you'll get the cleaner stuff that way, and most of the nasties will have settled out.

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I agree that the rest is probably okay. We might be using different terms. If by "nasties" you mean hop debris, then I agree. My experience is that the bacteria stay suspended better than the yeast. Typically if there is 0.5% bacteria per live cell in the thick slurry there is about 5% bacteria per live cell in the liquid at the top.

That big thick creamy white layer is the yeast.

WoodlandBrew said:

Has any one done cell counts to verify this? It's a common statement I hear, but my experience is that there is an even mix of live and dead cells between the layers. At one point Wyeast promoted this technique, but it seems they have removed it from their site.

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It totally depends on the yeast. The sticky gives fantastic directions for washing and getting really nice cell counts (verified by microscope). However, confusion sets in in cases (like this one) where the yeast flocs out really quickly. The creamy white layer is the best layer for live cell counts. Most of the time that is the stuff that stays in suspension, but not always.

WoodlandBrew said:

Has any one done cell counts to verify this? It's a common statement I hear, but my experience is that there is an even mix of live and dead cells between the layers. At one point Wyeast promoted this technique, but it seems they have removed it from their site.

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I certainly haven't, and can't claim to have any specific knowledge about the ratio of living to dead yeast in different layers. I looked at your work, and it's convincing enough to me. I was speaking from the perspective of cleaning the yeast of hop material, hot and cold break, etc--the other things that get deposited in the bottom of your carboy. I frankly don't worry too much about the ratio of living to dead yeast--don't yeast often eat their dead buddies anyway, one reason that people use dead yeast as nutrients? As long as there's a sufficient amount of live cells (something your starter should confirm), you should be good to go.

I hadn't thought about the bacteria issue...that's an interesting point, and one I suppose you would want to consider when pitching. I've never gotten an infection from repitching washed yeast (although that doesn't mean that I couldn't!), so I've never considered it an issue. If higher bacteria concentrations are present in the top layer, would that argue for pouring off the top layer and pitching the bottom layer instead? Interesting thought.

pabloj13 said:

It totally depends on the yeast. The sticky gives fantastic directions for washing and getting really nice cell counts (verified by microscope). However, confusion sets in in cases (like this one) where the yeast flocs out really quickly. The creamy white layer is the best layer for live cell counts. Most of the time that is the stuff that stays in suspension, but not always.

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I'm glad someone has done cell counts and got good results. That's comforting. However, I've done cell counts on four different strains, and not seen the variation. They were: WLP004, WLP566, S-04, and EC-1118.

Here are the details on the first three:
http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html

I don't remember seeing the cell counts in the yeast washing sticky. Could you please point me toward that?

WoodlandBrew said:

I'm glad someone has done cell counts and got good results. That's comforting. However, I've done cell counts on four different strains, and not seen the variation. They were: WLP004, WLP566, S-04, and EC-1118.

Here are the details on the first three:
http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html

I don't remember seeing the cell counts in the yeast washing sticky. Could you please point me toward that?

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The cell counts weren't in the sticky. They were in my hands. I didn't save the results, but I can do it again next time I wash.

WoodlandBrew said:

I'm glad someone has done cell counts and got good results. That's comforting. However, I've done cell counts on four different strains, and not seen the variation. They were: WLP004, WLP566, S-04, and EC-1118.

Here are the details on the first three:
http://woodlandbrew.blogspot.com/2012/12/yeast-washing-exposed.html

I don't remember seeing the cell counts in the yeast washing sticky. Could you please point me toward that?

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I just read that post. Can you describe when you took the samples? (i.e. did you take cell counts from the stuff left behind in the fermenter?). It's interesting.

jerrodm said:

I was speaking from the perspective of cleaning the yeast of hop material, hot and cold break, etc--the other things that get deposited in the bottom of your carboy. I frankly don't worry too much about the ratio of living to dead yeast--don't yeast often eat their dead buddies anyway, one reason that people use dead yeast as nutrients? .

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Yes, dead yeast makes good yeast nutrients. Also you are right that the viable cell count is more important than the viability. They are often used interchangably which can lead to confusion. Where it can be a problem is when the yeast is rinced with water the final volume is much smaller than the original. So if the viability is low, there are very few live cells.

jerrodm said:

As long as there's a sufficient amount of live cells (something your starter should confirm), you should be good to go..

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This seems true for the most part. One of my recent slurries was 1% when I harvested it. Out of curiosity I made a starter out of it to see if it would take off or if the bacteria would dominate. Because I used the actual live cell count to determine the pitch rate, and the yeast had just been harvested it took right off. I suppose if I had assumed 90% viability I would have seen very little activity.

jerrodm said:

If higher bacteria concentrations are present in the top layer, would that argue for pouring off the top layer and pitching the bottom layer instead? Interesting thought.

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After crashing the slurry I pour off the top and fill it back up with clean water. That lowers the alcohol level which is part of what protects the yeast, so I'm not really sure if this is the best technique, but time will tell.

pabloj13 said:

I just read that post. Can you describe when you took the samples? (i.e. did you take cell counts from the stuff left behind in the fermenter?). It's interesting.

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Those experiments were based on slurries that had been in the refrigerator for a period of time and then crashed in test tubes. A pipette was used to remove samples of each layer without disturbing them. I'm collecting data now on an active fermentation and am seeing the same mix of live and dead cells in the suspended yeast.

pabloj13 said:

The cell counts weren't in the sticky. They were in my hands. I didn't save the results, but I can do it again next time I wash.

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Awesome! I wonder why we are seeing different results. It would be interesting to see what the difference was in viability.

WoodlandBrew said:

Awesome! I wonder why we are seeing different results. It would be interesting to see what the difference was in viability.

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For sure. For me the biggest reason I wash is just to get rid of most of the hop debris and trub since I just put EVERYTHING into the fermenter. There is no question, though, that people have success direct pitching slurry. I also take my crashed yeast and freeze them at -80 with 15% glycerol so I can keep them long term, so I want them as clean as possible. I'll be washing again soon. Now I have an experiment to do. I love experiments.

pabloj13 said:

I love experiments.

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Me too! The sciency bits (that's a technical term) are the parts that I enjoy the most. I have one fermentation finishing up soon, and another in about a week. I'll re-read the sticky and follow it the best I can. It would be wonderful to be able to actually wash out 90% of the dead cells. It would make determining the number of viable cells much more accurate without a microscope. (Viability and thick cell density [likely driven by protein content] are the two biggest factors working against those not using microscopes, but that is a whole different discussion)

good info. Im still left wondering how to proceed....

Should I mix the slurry up again and wait for it to resettle to gauge the results before rewashing?

Or should I simply dump the top two layers of dark murkiness and clear beer and retain the bottom creamy white layers?

Thanks

bluelakebrewing said:

good info. Im still left wondering how to proceed....

Should I mix the slurry up again and wait for it to resettle to gauge the results before rewashing?

Or should I simply dump the top two layers of dark murkiness and clear beer and retain the bottom creamy white layers?

Thanks

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If a yeast flocs before the trub, simply allowing it to resettle won't do anything. Keep the creamy white layer. You don't have to get rid of the off-white layer. It won't hurt anything.

I had a similar experience with wy2007 lager yeast, I poured off the murky liquid, it still had some white yeast that settled out in the fridge, then i discarded the darker layer and saved the bottom white layer and recombined the two saved layers when I pitched.

I'm sure you will be fine either way, I was previously not washing my slurry cause I only rack clear beer to my fermenter.