I did some research, and many brewers beleive that top cropping yeast during active fermentation is a way to harvest the best of the yeast, and some claim that it is almost "super" in its abilities to attenuate and start up quickly.
I have a 1.052 american amber that was just starting to wind down after 3 days with pacman and there was a tiny layer of foam left on the top. I made 1 quart of 1.040 starter and just for the heck of it, i skimmed 1 tbsp of the foam from the top of the beer, with a sanitized spoon.
Woudn't you know it, this morning, that little bit of "super yeast" had a nice krausen going on my starter! I am going to step this up to a 2 litre starter and pitch into 1.055 IPA/APA type thing.
I am expecting good things, pacman always is a beast, but now I have cultured the best of the best!
Does anybody else have any experiences to share with top cropping yeast?