Black ring inside my fermenter

[Birdsnestbrewery]

I just bottled a batch of golden ale. When opening the FV afterwards I found a nasty looking black ring (see attached photo). There are no funky smells, and the beer tastes fine.
Does it look like an infection?
This brew was dry-hopped with 30g of whole hops which seemed to remain floating on the top. Could they have brought something with them?

 

[RichardM]

Perfectly normal result of fermentation

 

[Birdsnestbrewery]

Interesting, I have never noticed that before. Thanks!

 

[hoppyscotty]

give mine a good scrub with a scourer and washing up liquid before proper sanitising and gets the black ring off no worries. ON my larger fermenter that is harder to reach into the jet washer does a good job at getting most off and a good strong solution of hot Sodium Percarbonate in the CIP cycles removes the rest.

 

[Stan's Brew]

Looks like mine before I cleaned today, dry hopped also, pretty normal.

 

[Birdsnestbrewery]

Yes cleaning wasn't an issue, it came off easily. I don't remember seeing anything as thick and black before. Maybe the yeast (Gervin Gv12) which I don't use very often.

 

[hoppyscotty]

Only get it with my grainfather fermenter for some reason. I always get a Krausen ring but it’s only ever black with the grainfather. Wonder if I need to passivate it?

 

[Stan's Brew]

My stainless fermenter has a blast treatment that never requires passivating, so it might not be that.

 

[hoppyscotty]

I have a Brewtools fermenter also which has some form of coating or surface finishing that doesn't require passivating, but not sure the Grainfather has the same type of finishing treatment. My other fermenter is a Fermzilla and the krauzen ring isn't black either on with that and comes off easily with a sponge and some washing up liquid.

I'm not too fussed on the basis I always clean it off and doesn't seem to cause any issues.

 

[Agentgonzo]

I have a stainless BrewMonk fermenter. I've never seen this black ring

 

[Stan's Brew]

I have a Brewtools fermenter also which has some form of coating or surface finishing that doesn't require passivating, but not sure the Grainfather has the same type of finishing treatment. My other fermenter is a Fermzilla and the krauzen ring isn't black either on with that and comes off easily with a sponge and some washing up liquid.

I'm not too fussed on the basis I always clean it off and doesn't seem to cause any issues.

So this was in my Brewtools F80, the Grainfather doesn't have the same coating and I'm sure I've had similar on that, only brewed with the Fermzilla once, but many times in the Chubbies and not seen it in the plastic.

Amazed that we have the same fermenters