second half of the first pour (first part normal discarded)
first half of the second pour (part normally kept as clean yeast)
second half of second pour (second part normally discarded)
A couple weeks back I wrote a post about the results of "washing" four difference strains of yeast. None of them washed successfully. For completeness I decided to wash an entire slurry from a beer made with fruit to really allow the yeast washing to work. Although the washing didn't effectively separate live cells from dead cells perhaps it would be suitable for separating fruit partials from yeast cells.
In a nut shell yeast washing, or more accurately referred to as yeast rinsing goes as follows:
1) Add water to the slurry and mix. Wait 20 minutes.
2) Pour off the top part of the slurry that hasn't settled. allow this to settle for 20 minutes.
3) Pour off the top of the slurry into jars to save the "washed" yeast.
The result is much less yeast that you started with. In the picture above all three of the different stages were saved instead of being discarded so that they could be compared. The one in the middle is what would be saved. Notice how there is very little yeast in the jar. This has packed much denser than the one on the left, but the viability is about the same in all three jars.
First discarded yeast (pour 1-2)
Second discarded yeast (pour 2-2)
Retained yeast (pour 2-1)
In summary, yeast washing was successful at separating the fruit from the yeast, but at the cost of loosing an enormous about of good yeast. (95% of the total cells produced) If you just put the yeast into jars from the fermentor you will have 25 times more yeast that is about as viable as the water washed yeast.