Astringency from Fermenter Scum?

[krausenhaus]

My last few batches of beer have had a seriously unpleasant dirty astringency to them. I've been racking my brain trying to work out why, and this is the best I can come up with.

These are all double-batch brews and for one of them, one fermentor made it through unscathed while the other copped the taste. I usually add gelatin to all my fermentors but didn't for this one because I had ran out - so I'm trying to work out if it's something to do with my fining process.

Generally when I add gelatin to the fermentor (20L jerry can) I give it a gentle little rock just to disperse it through. I'm thinking maybe I've been getting a little too excited and washing some of the brown scum clinging to the sides of the jerry can into the beer. These have all been really hoppy beers so there would be plenty of resinous junk in there.

The other common factor is that I've recently set up a cold conditioning fridge in the shed and the fermentors have been making the journey from the fermenting fridge round to the back of the house, which I try to keep as smooth as possible for them but its highly possible there could be some more scum-splashing there too.

Does this sound plausible? Any alternate theories?

Maybe the WASABC judges can tell me what it is h34r:

 

[Markbeer]

does it settle out with age?

otherwise i would think possibility of infection.

 

[Screwtop]

Hmmmmm.............................. similar experience. Can you better describe the aroma/flavour? Do you Keg?

Screwy

 

[Online Brewing Supplies]

Bring some over, one mans descriptor ( unpleasant dirty astringency) is another mans guess.
Has the malt backbone gone to the beer ?
Nev

 

[Helles]

Have some experience with this too
Believe it came from krausion ring around fermenter too
Also read it at some stage too

 

[krausenhaus]

Sorry, I should've been more descriptive. It's kind of hard to describe. Yeah Screwy, I keg.

The up-front flavour and aroma of the beers are as they should be. This taste comes on the back of the normal hop bitterness and is a sharp, almost chemical-like astringent bitterness.

Nev I'll bring some over next week, it still smells nice and hoppy so it'll assault your senses all round.

 

[krausenhaus]

Anyone else got any thoughts on this?

 

[MaltyHops]

Could try transferring the beer into a secondary fermenter (towards the end of fermentation) so there won't be a krausen ring when you add finings to see if it makes a difference?

 

[boonchu]

Does it have that taste straight from the fermenter or only from the tap?

How long has it been since you've cleaned / replaced your beer lines and pulled apart and cleaned your taps?

 

[krausenhaus]

Could try transferring the beer into a secondary fermenter (towards the end of fermentation) so there won't be a krausen ring when you add finings to see if it makes a difference?

That's the plan, buying a couple more jerries today. Will rack into it straight from the fermenting fridge, purge the headspace and then move it around to CC and keg without the risk of splashing the ring.

Because I ferment very hoppy beers in jerry cans, i get a really high, chunky ring of scum surrounding a relatively much smaller surface area than a round fermenter would have. A little side-to-side rock to disperse some gelatin probably washes a lot of it in but it's something I never gave much though to.

Thankfully I had the batch where it only happened to half of it, which narrows it down to a cold side problem. Hopefully this solves it, but I'll also give the fermenting and CC fridges a good disinfection to make sure there's nothing lurking in there.

Does it have that taste straight from the fermenter or only from the tap?

How long has it been since you've cleaned / replaced your beer lines and pulled apart and cleaned your taps?

I think I've tasted it from the fermenter before but have put it down to having a mouthful of trub. I often only taste after ferment is finished and before I've cold crashed or fined it, so if it is a scum-splashing issue I would probably miss it most of the time.

I gave all my taps, lines and kegs a thorough clean not long ago but the problem persists. Also got it from bottles I'd filled with CPBF so I think it's safe to rule out a keg/tap issue.

 

[manticle]

Does it only happen with very hoppy beers? I ferment in cubes and get a similar krausen ring but notice no such flavour - however most of my beers sit between 30 and 50 IBU with very occasional ones pushing 60.

 

[krausenhaus]

Does it only happen with very hoppy beers? I ferment in cubes and get a similar krausen ring but notice no such flavour - however most of my beers sit between 30 and 50 IBU with very occasional ones pushing 60.

The last less-hoppy beer I made didn't have the problem, but I make them so infrequently that it's hard to draw a conclusion. This doesn't happen to every beer but does seem to have increased since I've started moving the fermentors considerable distances (fermenting fridge to CC fridge).

Do you use any finings? If so, do you rock the cube at all? I also remember you saying somewhere that you rack to a second fermentor, is that before you add anything?

 

[manticle]

I only rack to bulk prime or if the beer is going in for a few weeks lagering.

No finings.

Reason I ask is since you're testing to see, why not try a super hoppy beer and much less hopped beer, keep everything else the same - maybe apa and aipa with similar grist.

 

[krausenhaus]

I only rack to bulk prime or if the beer is going in for a few weeks lagering.

No finings.

Reason I ask is since you're testing to see, why not try a super hoppy beer and much less hopped beer, keep everything else the same - maybe apa and aipa with similar grist.

I have an amber fermenting now, brewing an AIPA today, APA next week and wheat the week after so should have a good spectrum of hoppiness to look at.

I'll report back whether there's any difference or if the problem ceases with the changes I'm making.

 

[Camo1234]

Why not just put the gelatin in the keg and rack the beer onto it.... That's the process I follow which will help avoid you needing to rock the fermenter to get the gelatin to mix.

 

[krausenhaus]

Why not just put the gelatin in the keg and rack the beer onto it.... That's the process I follow which will help avoid you needing to rock the fermenter to get the gelatin to mix.

I'm not sure why but that doesn't always work for me, sometimes I just keep pulling pints of concentrated yeast and shedding tears over wasted pints. I'm happy to start moving to secondary anyway because there's other aspects of it that I like.

 

[Bizier]

Is it always the second transfer with the bulk of the kettle trub?

That would potentially contribute astringency.