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Why this Pellicle?

I’m going to say this photo shows a pellicle growing on my beer. If anyone wants to tell me it is NOT that, I’d be grateful to hear what you think it is.

So - if it is a pellicle, what caused it and what to do about it?

This beer is about 3 weeks old. It is in the first fermentation vessel, a plastic Big Mouth carboy with an airlock, and a tap, since I like to use the siphonless models (which may be the problem).

This beer is a classic golden ale with British yeast that I did not add to a starter, just warmed and poured in. The recipe was mostly Golden Promise with some small adds of specialty malts but nothing unusual. The hops were exclusively 6oz whole cone Columbus I grew myself and dried back in September, then put in freezer.

My guess is I am failing to clean the carboy and the tap as well as I can, although my usual procedure is to take it all apart, soak the small parts in PBW solution, run the carboy itself through the Mark carboy cleaner with warm/hot PBW solution, and then on brew day spray with sanitizer Star San and soak the small parts in Star San solution.

My home brew shop guy said “you’ll be making vinegar…” if you go siphonless “…you can never clean those things…” and I am starting to think he is right since this is not my 1st pellicle.

Other beers have turned out perfectly drinkable - even great - after I siphoned right from under the pellicle layer to new vessel and bottled.

Thank you.

Yep, that’s definitely a pellicle. Nice one, too, if you’re into that kind of thing. Did anything touch your beer, after chilling, or did it go straight into the carboy? Something contaminated came into contact with it, whether it be the carboy, valve, tubing, straining mesh, etc. Can you walk us through the steps you take to get the beer into the carboy and pitch yeast?

When you say you spray everything down with star-san, that has me a little concerned. How fresh is the star-san? Are you sure you’re getting the surface wetted, and it has enough contact time? I only spray small items, like stoppers and airlocks when I don’t have a bucket of the stuff available. Otherwise everything gets soaked or partially filled, and shaken around to make sure it gets coated.

Are you fully disassembling the valve and cleaning it? How is your attenuation?

Just because it’s infected doesn’t mean that it will make vinegar. In fact, making vinegar is pretty tough if you keep it airtight. Could be wild brett (unlikely) that could overattenuate, could be lactic acid bacteria, could be something like pichia that could get citrusy or make it taste like a dead dog’s posterior. The biggest risk is overattenuation, and if you bottle this beer before gravity is done dropping, you could end up with bottle bombs.

My best advice is to bleach everything. That will kill the infection. But bleaching won’t do any good if the stopper isn’t being fully disassembled to clean. And step up your sanitation game, I regularly share equipment between clean and mixed fermentation batches, and have not run into cross-contamination issues.

I boil my water for sanitation and let soak.

I see a couple things to look at. The hops you dried. How? Could’ve picked up something on the outer part of the cone… I also like what Pork chop sez about a “spritz” of star san and is it low enough in ph? Try make up a couple of gallons of star san, put that into a couple of jugs. On brew day, I will pour a gallon into my fermenter, shake it vehemently and allow it to lay on its side. Every 15- 30 minutes repeat and and then roll it about a 1/4 turn to allow the solution to touch as much of the fermenter as possible. I do pour the solution when its time, back into the jug for another time. Sneezles61

Thank you Pokchop for the great answers. Here’s my follow up…IN CAPS



Hey Sneezless,

Thank you for the good points/questions.

My hops in this case were dried on a dehydrator right after picking, and left for about 8 + hours. Then I stuffed them into freezer ziplocks and put into the freezer after I by hand pressed out as much air as I could.

I will definitely try your fermenter move with the Star San. Thank you.

What about Star San solution running through the Mark keg and carboy washer? I use that for the PB cleaning process after hand washing my Big Mouth fermenters.

Thank you

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While I agree that spraying may not cover the entire surface with sanitizer, @sneezles61’s process is overkill IMHO. All you need to do is coat the surface. Put a quart or 2 of starsan in and swish it around to cover all surfaces then dump it out. You’re good to go.

I had a very similar looking pellicle that I believe was acetobacter. It definitely made vinegar.

After a pellicle like that I would replace any plastics that came into contact with that wort, buckets, hoses, tubing, racking cane, etc. Some will say bleach will clean it up but I’d err on the side of caution. YMMV

Yeah, I do about the same. Mix up a couple gallons of star-san on brew day, pour a gallon into the fermenter, and give it a good shake. I might do this a couple times while the wort is chilling, although it’s not necessary. Depends how long it takes to chill and how impatient I get. I always give it a shake and pour it out right before filling it, though.

Probably best to invest in a new fermenter. You can probably kill the infection, but how much do you really want to risk a new batch versus the cost of a new fermenter? I’d suspect that bacteria are lurking inside that spigot. They usually can be disassembled fully if you stare at them long enough, and soak them in hot water to loosen up all the fits. You can kill an infection with bleach (and heat, depending on the materials), but often times it’s just easier to replace the soft materials, like @dannyboy58 said.

Not that this matters, but I ran across something I posted here over a year ago:

I’m pretty content with my way of preparing my fermenter. Many years ago I was lax, well, I tossed out 2 batches. I haven’t since using this method. Since me fermenter is “just laying there”, heck why not? :sunglasses: Sneezles61


Star san will foam up too much for a pump to work effectively. There are some products out there that will work. Sneezles61

SaniClean is what you’ll want if you’re running a pump non-stop.

I do admit to using star san through a pond pump for my keg washer during the sanitization. But it’s a brief 10 second blast per keg.

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