Re-using yeast cake from high gravity fermentation

Hi,
Transferring a Baltic Porter at the weekend to secondary for lagering. It started at 1092 and Finlay finished at 1023.
So going to have a hefty amount of whitelabs German bock yeast left and would kind of like to make use of it. So am thinking some massive Imperial Stout or something.
But... Some questions.

I have some vague memory of someone saying you can't reuse the yeast cake from a high gravity fermentation because it is worn out. Anyone else know anything about this?

Also, because it is such a vast amount of yeast in there is it possible to get off flavours from using too much yeast in a brew?

And finally, recipe wise, i have some centennial and chinook hopes i want shot of, i know they really are not hops you would use in a stout but has anyone ever used them in a dark beer like this?

Last but not yeast anyone got anything at all to say about this yeast. I am quite impressed with it. The Baltic Porter has come out smooth with great balance between hops and malt flavour. Highly recommended strain!

Thanks for the tip regarding Baltic Porter yeast. I'm not a huge fan of raking off yeast from spent fermentations for the very reason you mention ... risk of off flavors. I've found that splitting yeast starter is a cleaner and better way to go.

You will get several people tell you that you can do it.  But, if you are trying to make the best beer possible, then you should NOT. 

1.  Yes, the yeast is "tired".  Basically, they have bene badly stressed and weakened by the OG of the wort, and the alcohol of the beer, and the time they have been living in these conditions. 

2.  If you reuse the entire yeast cake, you run two risks:
  a.  not developing enough flavor due to a lack of growth.  You WANT the yeast colony to grow about 4x in your beer.  It makes many of the flavors that we taste and enjoy in beers.  Without the growth you don't get the right flavor profile (ie. bland and flavorless).
  b.  Having some of this yeast die and produce autolysis flavors (nasty).

3.  If you were going to reuse this yeast, you should wash it with sterile water and repitch the CORRECT amount of slurry, not the entire cake.  You should also probably remake a starter with it, and lots of O2 to improve its viability and vitality.  But, again *I* would not.

As I said at the start, you could do what you suggest, and it will certainly make "beer".  Many people will tell you that they've done it and it came out "fine".  Have you had their beer? How do you know to trust their definition of "fine"?  Every beer and yeast expert in the world will tell you what I've said above. 

tom_hampton said:

3.  If you were going to reuse this yeast, you should wash it with sterile water and repitch the CORRECT amount of slurry, not the entire cake.  You should also probably remake a starter with it, and lots of O2 to improve its viability and vitality.  But, again *I* would not.

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I agree with Tom.  I would love someone that makes bigger batches to split a wort between a washed/re-started yeast sample and the remaining yeast cake.  I guess it would require a conical in order to get some yeast off in time to do the washing and starter, but it would be interesting to see what difference the yeast does make in this comparison. 

Cheers everyone, reckon I'll give it a miss then. Gives me a chance to try a different yeast.