Brewed a stout 2 weeks ago, 1.070 OG. Checked the gravity after a week, 1.020, krausen was still hanging out. Checked it a week later (today), gravity still at 1.020, krausen still there. Fermentation still seems to be plugging along though; small bubbles were evident in the sample I took (which tasted great). Incidentally it tasted carbonated as well. I realize some yeast do not like to floc, but WLP001 shouldn't have this issue. FWIW my plan is to let this guy go for at least another week. Little more info: partial mash riff of a Jamil American stout recipe 2# american 2-row 1# black roasted barley 0.75# choc malt 0.75# crystal 40 0.5# flaked wheat (leftover from a previous recipe) 6.6# light LME 0.5# pilsen DME (leftover from a previous recipe) 1oz warrier at 60min 1oz centennial at 5min 2L starter of WLP001 pitched at 72F, fermentation held at 68-70. Jamil listed an OG and FG of 1.072 and 1.017, respectively. All this brings my to a question: what's the longest time you all have seen the krausen stick around?
I've racked from under a krausen that never fell. Your beer has the same SG after a week? It's done. Bubbles are a poor indicator of fermentation as changes in temperature and pressure can drive gases into and out of solution.
You're taking hydrometer readings, that's what really matters. I've had krausen fall 2 weeks before my beer got to FG. I ferment most of my beers in a stainless conical so I can't easily see krausen, but if I don't see any activity from the blow off hose I'll peek inside to see what's happening. Invariably there's krausen so I wait a couple of weeks to check the gravity, but if there is still krausen or not I'll never know.
I often have a "cabonated" beer in the primary, which I initially took to mean it was not finished (gravity readings notwithstanding). Obviously if gravity isn't moving then it's finished for the most part, but is it possible the yeast is still working in a less active fashion? When I add priming sugar before bottling these same yeast still convert it to CO2 and alcohol. I know some yeast types (brett for example) take a long time to munch their way through the fermentables.
Yes it is, but you would see a drop in the SG, even if it were only a point. In the first three weeks, you should see a drop in a week. The reason carbonation works is that the yeast has now found more sugar it can munch on which you just added, the yeast are at this point done munching on what you gave them for the first round and are waiting for round two. They are not weak or dead or needing revival, rather they are in a hold-like state. The carbonation you are tasting / feeling is the CO2 that is in solution (that's where it starts, and only after the solution becomes saturated - a function of temperature - does it bubble into the headspace and through your airlock)
Thanks for the info and suggestions--I'll rack it to secondary under the krausen and let the crap settle out for a while before bottling
No big deal, carry on if the gravity is where it needs to be and is stable. I had a DIPA that had hella krausen. It wouldn't budge.. Then one day I came home from work and it was all gone.. like, not a bubble to be found.
Just racked it to secondary a little earlier. Two days ago krausen, today nothing. It does make me wonder why the time before it falls is variable from batch to batch with the same yeast. If it was correlated with activity it should have dropped out when the fermentation stopped a week ago. Guess I'm showing my ingorance on the finer points of flocculation. In any case I think I'm going to like this one a lot--smells and tastes delicious! The hops aren't popping right now without carbonation but the bitterness is just right; the roasted malts are nice on the nose too.
