re-using a yeast cake...

Correct me if I'm wrong, but wouldn't there be plenty of esters in the cake from the previous batch?

 

My "whole cake" Barleywine had/has plenty of esters. (not a Belgian, but seemed relevant)

 

I think it might depend on the yeast. The alchemist has been rumored to under pitch his yeast to get more fruit character from Conan. If you over pitch with a yeast cake or with washed yeast from a yeast cake it would stand to reason that beer probably wont taste the same. Im a little concerned about that with my most recent beer, we will see though...

 

My point is, wouldn't the first fermentation stress the yeast sufficiently so that the stress-derived flavors are already there? No need to stress it again. I'm not an expert on this - this is truly a question.

 

The yeast turn on and turn off different biochemical pathways depending on how many cells are present in the wort. So no, you don't get the same products like the ones that produce ester flavors when you pitch higher as when you pitch lower.

 

I'm not an expert at all, but that is not what I inferred from my readings of Yeast. Quick find someone who understands bio-chem and fermentation

 

Aren't there other factors that influence ester formation other than yeast amount? (such as yeast strain, oxygen, and temp., etc.)

 

There are absolutely other factors, but we are just focusing on pitch size. If you include the other factors, you may influence the yeast to produce more esters, but I'd say pitching onto a yeast cake isn't one way to increase the amount of esters produced.

If you want to gain control over the whole process, I'd say understanding the way treating yeast influences your final product is essential to creating the beer you want to produce.

 

FWIW count me in that first group, too. I don't usually dump the next batch on top of the first, but swirl the sludge around a bit and scoop a couple of cups into a clean container and refrigerate until brew time. It usually gets used within a 10 days to 2 weeks, but I've kept in longer with good results.