Is fermentation 'done' even without there being cake?

Question

This one has me questioning what I thought I knew. Brewed a "mocha stout" 4 days ago: Steeped: - .5lb chocolate malt - .375lb roasted barley For boil, added: - 6lb DME (dark) - 1lb lactose At flameout, added: - ~8oz cocoa powder - 1qt brewed coffee

Problem #1 is that I broke my hydrometer, so did NOT get an OG. Cooled wort to 70F, then pitched two packs of Wyeast Irish Ale 1084. (I did not use starter because I had the yeast for a different brew in there.) Sealed the brew bucket and inserted airlock.

I saw very little activity in the airlock, which didn't concern me that much. Today, I opened the bucket to rack to secondary. There was no krausen. None. That's a first for me, but didn't bother me. Gravity was 1.020, which is what my calculated target gravity was to be. Racked it to the secondary and discovered that there was nearly NO cake!

Question then is, is it possible that fermentation occurred fine without there being much cake at all, and no krausen? Looks, smells, and tastes pretty much as expected, just surprised by the lack of what I've come to know as my tell-tale signs of fermentation.

Thanks!

Answer 1

If the gravity has dropped, you had fermentation. So, the answer to your question is yes, it's possible.

Answer 2

Krausen itself will definitely fall back into the beer once fermentation finishes; you should see some residue/evidence, but you should only really see krausen while it's actively fermenting ("high krausen").

The trub/cake consists of a number of things: coagulated proteins, hop residue, other solids, flocculated yeast. 1084 is listed as a "medium" flocculator.

I'm going to guess it's some combination of: not a whole lot of residual solid materials to drop out of suspension in the first place, and fermentation not really being fully complete after only 4 days, especially with a medium-flocc. yeast.

Sufficient time and low temp ("cold crashing") are things people do.