Solvent smell

[gongfu]

Brewed a Scottish ale (OG 1.069) with S-05. Fermented for 3 weeks at 65-66 deg and finished at FG 1.017. When fermenter opened the solvent smell was overpowering and beer had some small tan spots on the surface (like somebody sprinkled pepper flakes on it). In the bottling bucket, however, no off smells and no off flavors. What was going on?

 

[bucketnative]

Small tan spots, most likely = yeast rafts, and are totally normal (barring photos that prove otherwise).

Solvent smell? Did it burn your nose? Most likely CO2, which will do that when you breathe deep. Or it's just some alcohol vapors plus other smells associated with normal fermentation.

 

[RPh_Guy]

Can you post a good photo?

 

[gongfu]

Can you post a good photo?

Here's a photo; color of spots more tan than appears here.

 

[day_trippr]

Looks totally benign.
Carry on...

 

[RPh_Guy]

In my opinion, it's hard to tell whether that's a pellicle or "yeast rafts".

Make sure to open bottles periodically to make sure they don't over-carbonate.

 

[day_trippr]

fwiw, I believe a lot of what would be "scary" is a reflection from the sides of the fermentor.
If that was actually riding the surface of the beer I'd agree there might be something going on...

Cheers!

 

[IslandLizard]

The little slimy bubbles on top of the rafts/pellicle look suspect to me. But most pellicles tend to cover quickly, starting as a haze. You've got very clear beer between the rafts.

Have you tasted some of that beer? If it's totally weird tasting or undrinkable now, it'd probably chuck it. Definitely not going through the effort of bottling it.

Was that fermenter used before? Is it stainless?

 

[RPh_Guy]

I believe a lot of what would be "scary" is a reflection from the sides of the fermentor.

I know. I think the patches are possibly suspect. That is how a pellicle formation often begins.
Could it just be residual kräusen? Maybe.

But most pellicles tend to cover quickly, starting as a haze.

Not in my experience.

 

[gongfu]

Thanks to all for your input. Fermenter was glass "Big Mouth" and beer tastes and smells fine. I've bottled but left enough behind to toss the floaters. Will open a bottle or two as carbonation proceeds. I've attached an online photo (not mine) showing color of floaters that better approximates what I observed. I never experienced (in ten years) the smell or floaters like this before so was a bit freaked out. We'll see.

 

[RPh_Guy]

The color in this photo points toward it being leftover kräusen / yeast rafts.