On page 63 of Brewing Better Beer, Gordon Strong says,
Some of the cold break material can actually help the yeast, but too much can contribute off-flavors.
I can attest to both of these. A couple of times I have,
- let the trub settle for a couple of hours
- racked the really clear wort to a fermenter
Since I was left with a bit of trub that had a bit of nice wort in it, I fermented a bit of it in PET bottle. The fermentation took off extremely fast. But the resulting "beer" had a pretty nasty smell.
My question: Can anyone tell me what the off smell/taste from excess cold break is? Is it one of the common ones, like diacetyl, acetaldehde, etc.? I couldn't identify it, but it was pretty distinct. I often detect this same aroma at bottling time, but it always goes away soon after bottling.