Did I screw this up?

So here's a picture of my washed yeast starter that I made from a British Ale yeast, as you can see the trub layer is thick and the yeast layer isn't as much. Wondering if I'm still in the clear to use these or not if i decant enough of the liquid. Let me know people!

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I usually try and get rid of most of that trub. It will probably work fine for ya but I would wash it a few more times!

 

There's a sticky around here with pics about how to wash yeast, super informative and useful. I reckon you need to get rid of that trub

 

Totally used the sticky your talking about my man. I guess I'll just wash them again. It's a fairly simple process.

 

It looks backwards....the lighter layer is usually the yeast, and that English yeast can look like "brains" and drop out quick because it clumps so much. I think that lighter layer is your yeast, which means you have a good amount there.

 

I thought it was the other way around???

 

It normally is, but the trub is almost always darker than the yeast. Some English strains clump together a lot more than normal yeast and this can cause them to drop out quicker than the trub.

 

Wow so its safe to say that that bottom layer is all yeast?? That's great news for sure!

 

That yeast looks perfect.

From doing cell counts on washed yeast I have found that the only difference in the two layers is cell density. The viability is about the same all the way through. The only significant difference I have seen apart for density is that the liquid at the top usually has more bacteria per viable cell.

I just pour the top off, add clean water, then shake it up, do a cell count, and measure out what I need to pitch.

For more information on cell counts see this:
http://woodlandbrew.blogspot.com/2012/11/counting-cells.html

 

Sweet link and nice work, keep it up!

 

I sort of assumed after all the reading that I've done, that the thinner top layer is yeast and that the denser layer beneath it was actually trub. Your saying BOTH are yeast layers with varying viability levels?

 

That is what I have read as well, but it hasn't been my experience. The two layers seem to have the same viability but with different densities.

The comment that I made earlier was not meant to be a blanket statement, but more a recount of an observation that I made recently that might be relevant to the original post. The processes that you use may be different than mine. I harvest my yeast at bottling time, so it has sat inactive for about a week after fermentation completion, and has been in the refrigerator for about two days. The yeast is therefore likely dormant.

My observations seem to indicate that when dormant yeast is re-suspended in water (not wort) that the live cells and dead cells do not separate.

For curiosities sake below is data from three slurries of a wide variety of viability. The "deviation" is the standard deviation of the data for that particular count. It is a general indication of the accuracy of the data. The actual number of cells counted varies from about 20 for the liquid on top to several hundred for the thick slurry. Which is why there is a much larger deviation for the top liquid than the bottom.

Code:

WLP004 27 days after harvesting
Layer       Viability     Deviation    Viable Cell Density
Top         6%            -            0.04 billion / liter
Middle      9%            13%          36
Bottom      7%            30%          6

WLP566 6 days after harvesting
Layer       Viability     Deviation    Viable Cell Density
Top         99%           14%          36 billion
Middle      98%           10%          1,386
Bottom      97%           10%          1,617

WLP566 57 days after harvesting
Layer       Viability     Deviation    Viable Cell Density
Top         20%           36%          2
Middle      57%           10%          812
Bottom      53%           16%          1,552

WLP56 58 days after harvesting
Layer       Viability     Deviation    Viable Cell Density
Top         12%           35%          0.017
Middle      42%           16%          514
Bottom      48%           10%          1,844