Strange Film In The Glass And Bottle

[Kai]

This is an alt that I brewed recently. I went to sample a bottle tonight and noticed a film in the neck of the (clear) bottle that I assumed was dusty yeast. However, when I poured the beer into a glass the film went in too, more specifically the film travelled up the side of the glass ahead of the liquid like a hydrophobic substance. As you can see in the pic, it just looks like a dirty glass but it's the way the film behaved that's got me puzzled. What could it be?

The brew was a partial using K97 dried yeast. The grain bill was munich, pils, melanoidin and carafa sp2 plus 1.5kg LME and 300g sugar. I used 78g spalt split 50/50 FWH/60min to achieve 40 IBU. OG was 1.057, FG 1.013 and the batch size was 20 litres.

The beer itself had an extended secondary because I did not like the taste of it and did not feel like bottling. I thought the k97 had thrown up excessive clove flavours. As the beer is aging the taste is improving, though it has only been in bottle two weeks which is usually not enough time for my beers to condition. I have not checked any other bottles to see if they exhibit this condition, I've drunk enough for the night. The beer also had no head but that is normal for one of my beers after two weeks in bottle at low ambient temps and a low priming rate.

My thoughts are that it might be that single bottle that had some sort of residue left within it, or the k97 has done something funny (never used it before), or I was considering as an outside chance that it was hop oil but I don't think I used nearly enough for that to be an issue. Other than that I do not know what it might be. Does anyone have any thoughts?

 

[Screwtop]

As you said the film appeared hydrophobic. Was there anything in the glass, was it hot water washed and rinsed. Still you did say the film was also in the neck of the bottle. Sounds like something insoluable maybe, either in the fermenter or bottle. Whatever it was, it was obviously lighter than the beer and left a film on the inside neck of the bottle, then came out on the first pour and repelled up the glass away from the beer as you poured.

Thats my 2 bob's worth.

 

[T.D.]

I think this is one of a million potential things it could be, but anyway, it sounds a little bit like it could be an acetic bacteria infection. Did your brew have any white scum form on the surface at bottling? It is usually caused by vinegar flies spreading the bacteria. Depending on how bad it is, you can get a ring of the scum form on the neck of the bottle (although, I have never heard of it happening in the glass too). If your bottles have it, it should have been pretty obvious in the fermenter - the surface of your wort would have been covered in a white scum - sort of like webbing.

If it is this problem (and as I say, there are probably a million other things it could be too) you generally get around 3 months in the bottle before you start to notice a harsh sharp flavour coming through (caused by the infection). So if it tastes good now, unfortunately that doesn't mean you are in the clear. If you did have the white scum on top of your beer in the fermenter, you should probably plan to drink this one within 2-3 months. Hopefully it is something totally different though!

 

[Darren]

could be a pediococcus pellicle

 

[colinw]

I have seen this kind of behaviour in non-infected beers with extreme top-cropping type German ale yeasts - 1338 and K-97 are both in this category.

Generally happens when the beer is under attenuated and the yeast "wakes up" and comes to the top when you pour a beer.

 

[Kai]

I don't think the beer was underattenuated, I was looking at around 76% apparent attenuation though I'm not sure what's normal for that yeast. The beer was nicely clear too, though it took a long time to get there.

With regards to infection, the krausen was not pretty, but there was no webbing and no stringiness and the beer is not turbid. There are little bits floating in the bottle, though. They look like flecks of hops like if I'd used ground up plugs or something, but I shouldn't be seeing them from using pellets.

I'll see if it develops any off-flavours over the next couple months.

 

[T.D.]

If it was acetic bacteria, it would have been obvious in the fermenter. I doubt anybody could miss it. So that's good news. Probably still a good idea to keep the idea in the back of your mind, but it looks like its probably something else - probably totally normal. Good to hear!

Oh and if there are any Uruguayans on the forum, nerni nerni ner ner!!!!!! :super:

 

[Kai]

Well, I'm drinking another bottle right now, no film but it doesn't taste too thrilling. At this poing I an inclined to blame the yeast; it is the biggest difference between this batch and any other.

 

[Kai]

However, now I am inclined to say infection. My american wheat beer has the same film on the sides of the bottle-neck and a skin on top. It's only half a week in the bottle, I tried one and it's tasting ok so I'm hoping it will condition quickly enough for me to drink the batch before it goes rank. The alt is a writeoff. At this point I would guess that darren's post was right and it's pediococcus

Tonight will be spent having a few quiet beers and thoroughly cleaning one fermenter and one secondary vessel.

Oh well, there's a first for everything

 

[Zwickel]

Hi Kai,

it could be Kahm.
Kahm-Yeast or Kahm-bacteria (I dont know, if the englisch synonym is similar to the german one) produces a kind of bio-film, a closed bacteria film can be established.
Often it appears in aquarium.
Kahmhefen are aerobe yeasts, which metabolize alcohol and organic acids, thus the components of beer and wine.

cheers

 

[Kai]

Hi Zwickel,

Thanks for the info, but it's bloody hard to google more info from the perspective of someone with less than rudimentary German. Does Kahm impact the flavour in any way?

 

[Screwtop]

A quick check of some Germanic sites indicates that the incidence of Kalm is associated with diacetl. Could not establish if it is one of the more than 30 viariants of pediococcus (a lactic bacteria which requires an anerobic environment). Is it possible the brew was on the yeast in high temp for too long.

 

[Zwickel]

I found a translation-machine, maybe the result is very funny:

A layer formed from bacteria and other micro organisms in form of a whitish-grey skin, which grows on nutrient liquids very rapidly. The Kahmhefen in such a way specified is oxygen needet and can be formed after the fermentation several millimeters strongly at the wine surface (Mycoderma vini = wine mushroom skin), if the vessel is not bungful (see in addition under bung) and by the oxygen blister a rapid grow of these bacteria takes place. The wine-harmful Kahmhefen breathes alcohol to acetic acid, acetaldehyde and carbon dioxide and functions as support for acetic acid bacteria sees additional under Acetobacter). Young, alcohol-poor wines with small content of sulfur dioxide are particularly susceptible. If this arises...

Does Kahm impact the flavour in any way?

sorry, I dont know, I never caught it.


cheers