Krausen still floating, wait for SG?

[Ziggybrew]

Should I not bother taking a sample for SG if I see krausen still covering the surface of the beer? I don't want to disturb the beer unnecessarily. Wondering if this is another indication that fermentation is still in full swing and should just wait for it to dissipate before worrying about an FG.
Normally, I am used to seeing just clear beer surface with that gooey ring of foam around the edge of the fermentor when I go in to take an SG. With this batch, the activity in the air-lock slacked off so I opened her up on the 8th day only to discover the foamy krausen still covered the surface. (yet the SG was at my suspected FG anyway) I'll check the FG in a few days anyway. Just wanted to know for future reference so I'm not disturbing the beer before it is time.

 

[danielinva]

Yeah, I would just leave it alone at this point. Give it another several days to a week. You want the fermentation to be complete, not just slacking off before you look for a FG.

 

[Revvy]

It depends on how long it has been. Generally speaking the krausen should fall after 7-10 days or so.

I have a wit beer that I pitched bottle harvested Hoegaarden yeast on Dec. 26th, that STILL had a 2" krausen on it three weeks later. I took a grav reading and it had reached terminal gravity, 1.010. So the beer was done, but the krausen still lingered. I finally gently swirled the beer to knock it down, and let it settle for another week before I bottled it.

 

[Ziggybrew]

Thanks! So you’re saying krausen will usually fall back in after fermentation is done. I should wait when I see this in the future because it is normally a good indicator that fermentation is still going on. However, in some circumstances, the krausen may still float after FG is already achieved. --it’s better to just wait and see. (learning every day!)

 

[Revvy]

Thanks! So you’re saying krausen will usually fall back in after fermentation is done. I should wait when I see this in the future because it is normally a good indicator that fermentation is still going on. However, in some circumstances, the krausen may still float after FG is already achieved. --it’s better to just wait and see. (learning every day!)

Yeah, it's supposed to fall when fermentation is complete, and it kinda filters the beer as it falls, pulling down stuff with it. That's why I'm not normally a fan of knocking them down, and let it do it naturally.

But some yeasts are low flocculating, and may have a difficult time. I figured since mine was bottle harvested, and I had pitched the starter at high krausen, maybe it was "genetically mutated" with the flocculation "gene" off or something. So I gently swirled it and let it fall.

Again, it just goes to show that visual cues like airlocks and krausens are not 100% accurate indicators of fermentation, and the only accurate measure is the hydrometer.