Slime on surface of beer in 2nd fermenter

What went wrong? Was this supposed to happen? Should I throw it out? What do I do now?

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Slime on surface of beer in 2nd fermenter

Postby lootcorp » Thu Jun 09, 2005 11:23 pm

Looking at my first batch of beer in the secondary fermenter, I noticed lots of stuff on the surface of the beer.

When it was racked to secondary, it had a lot of airlock activity and now there is a 'scum line' maybe 1/4 inch above the beer.

What I first thought was little circles of mold on the top (nearly had a heart attack) turned out to be clusters of tiny bubbles, which I assume are CO2. There are also a few specks that look like some sort of spice, which I assume was the 'lemon extract' spices that came with the kit (instructions were to add them early in the boil and leave them in). Do those two sound plausible?

The real part that bothers me is there's some sort of sheen on surface of the beer - looks sort of like an oil slick on water. It's not really dark, and I only saw it when shining my flashlight and looking at the surface from an angle while trying to figure out what the bubble colonies were.

Is this normal, or do I have the start of some kind of trouble?
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Could be Anything

Postby BillyBock » Fri Jun 10, 2005 5:07 am

Loot: Different strains of yeast will have different fermentation characteristics. The scum line you saw is normal. Sometimes they look slimy, other times not. The stuff you saw thinking it was mold is clusters of CO2 (I remember thinking the same thing when I started). You'll see all matter of stuff floating up and down in the fermenter that just looks odd--but it's ok. You'll have flecks of trub, or other proteinaceous material, clumps of yeast colonies, etc. They get buoyant due to the CO2 and then rise, once they get to the top they lose their buoyancy and fall. There could also be leftover hop residue. How much 'junk' you get in your fermenter depends on your transfer and cooling procedures from the boil kettle.

As far as the sheen, from time to time I've noticed the same thing on my beers. I would ask what temperature you fermented at? It could be fusel alcohols (aka fusel oils) if it fermented too warm. Remember there are a lot of organic materials with organic oils in your brew. Another source could be hops. If you had a late hop addition that didn't have time to isomerize in the boil, you'll see a sheen also due to the hop oils. It could've come from your lemon extract addition. However, if you used some new stainless equipment without a good wash first that may be a cause as it usually has a light machining oil on the surface. It could also be something in the water. A lot of places are using chloramine, instead of chlorine, to disinfect the water supply. As I understand it, some forms of chloramine have an oily appearance (I still have to check into that further). But you can see my point here...it could be just about anything. Next time you're concerned about it look at the surface of a cup of coffee...there's a sheen too from organic oils.

But if your equipment and procedures were clean I doubt you have much to be concerned about. Let the batch ride out, bottle, and carbonate it. See what the finished beer looks like, smell and taste it. Pour it in a glass. If oil is present (the kind that's not supposed to be there), a head will disappear quickly on the beer. [To see the effect as a test, stick your finger on the top of a beer head, or eat potato chips and drink from the glass--the foam will recede.] At that point make your decision.

Good luck.

v/r
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Was sort of a warm ferment

Postby lootcorp » Fri Jun 10, 2005 10:51 am

Thanks for the info, I was thinking along the same lines, but seeing as how this is my first batch I have no prior experience to go off!

Your comment about the fusel alcohols and warm ferment worries me a bit...I was worried about fermentation temps being too cold, so I got a brew belt (the little warmer belt) and put it around the fermenter. Samples I took towards the end showed the wort temp to be between 76-78 deg F, which I now realize is probably a bit too warm for ales.

This info will certainly help my next batch, but for this one, if it was fermented too warm, is there anything I can do to reduce the fusels in the beer? I plan on siphoning and leaving some beer behind in the secondary, hopefully leaving that 'oil slick' behind with it. Is there a telltale taste or smell of fusels? in all taste tests so far, tasted like beer :)

I still plan on bottling and seeing how it goes, but if there's anything I can do before bottling (tonight) which will help make it better, I'll give it a shot.

Thanks!!
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cold conditioning

Postby lootcorp » Fri Jun 10, 2005 12:00 pm

as an add-on to my last post, how should I condition these beers in the bottles? warm? cold (ie, just put the in the fridge?)
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room temp

Postby richanne » Fri Jun 10, 2005 1:12 pm

Let the beer carbonate at room temperature (75-78F)
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Temperature Control

Postby BillyBock » Fri Jun 10, 2005 6:50 pm

Warm ferments give rise to esters and fusels. Esters have a fruity aroma. Fusels have a solvent-like aroma. Esters are ok--it's a natural part of the 'ale-iness' of an ale. Some beer styles purposefully have fusels. I particularly don't care for it. Not all yeasts are created equal though...some are better at warmer ferments and some aren't, some throw off more fusels, and some don't. Fusels can give you a pretty bad headache. Been there, done that. Don't want it.

Temperature control will be your friend. If you have a spare fridge or freezer and hook up a external thermostat, you can precisely control the ferment temperature. Also remember, fermentation generates its own heat. In my experience it seems to be an extra 5F on average. I had one batch that increased it 10F! So if your room temperature is 76F, your beer could be fermenting in the low 80s.

My opinion: After you get done bottling it, let it carbonate at room temp for 2 weeks, and then cold age it. Try one and see how offensive the fusels are. If it warrants more aging, then leave it in the fridge for 1, 2, 3 months, it should mellow it out. Cold aging does wonders.

In my brewing the single most important improvement that helped me make awesome beer was temperature control. I use an upright freezer with a temperature controller and do lagers and ales. FYI, I ferment my ales at 65F normally, and my lagers at 45F-50F.
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