Yeast Harvesting from Secondary

I don't do it every time, but I have washed yeast once I rack my beer to a secondary.  After the beer sits in the secondary, more yeast settles out of suspension, and is evident when I then keg/bottle.  Perhaps this is a stupid question, but can that yeast be harvested as well?  It would stand to reason that it would be more "pure" and hardly any trub to contend with.  Has anyone done this?

It can, but think about the selection pressure that you are putting on the yeast?  What is the property of the yeast that is still in suspension?  It will be yeast that stays in suspension longer---much less flocculent than the original strain.  Also, generally less flocculent yeast is also more attenuative because it has more contact time with more beer. 

It doesn't take long at all to have a yeast that doesn't resemble the strain you purchased and that the recipe calls for. 

Will it work?  Yes. 

Will it make the same beer twice?  Maaaaybe.  Will it make the same beer 3 times? not really, no.  Harvesting from the primary will be more consistent across generations. 

But, if you want to see what happens go for it. 

I agree with Tom.  I only harvest out of the primary for the exact reasons that he stated.

catch 22, the question you asked about the 2ndary yeast is the best question I've herd asked in quite some time. I also would agree with tom and scott on the yeast changing faster. The funny thing is with me, now that I have read this I must try it. guess I will have to get out the 1 gal fermenters again.

The only thing I can think of as being a good reason for harvesting out of the secondary, is if you want to make a really cloudy wheat beer some day.  You could use a strain of yeast that's already less flucculant and then harvest a couple of times out of the secondary to make it even less flocculent.

However, this doesn't really make sense, when you can just purchase a pure less flocculant strain that's already what you want, instead of trying to alter your yeast through natural selection.