Infection?

[steev]

Just got home from work,checked my beer that's been fermenting for 3 weeks and its starting to develop a white film on the top...what is this? And is it still gonna be drinkable?

 

[eastoak]

if you see a pellicle on your beer it has been infected with wild yeast or bacteria. hard telling if you'll like the taste, do you like sour beer? some of these infected beers taste fine early on then get sour after some time.

 

[RM-MN]

Infections rarely start in the primary because the organisms that can infect beer don't like the alcohol, the acidity, or are aerobic and the CO2 layer present in the primary stops them cold. A slight film may be just a reaction of the beer to the minerals in your water. I've had that and it didn't affect the beer at all. Give the beer another few days to perhaps a week and check again. If the layer hasn't changed, you're not infected. If it has grown solider you have a problem.

 

[steev]

So if I bottle it will that film be present in the bottle?...

 

[fearwig]

Three weeks? Isn't it done?

Take a sample and taste. If your beer is souring, this is an infection. You can also post a picture. When I hear "white film", I think pellicle. "Oily film" or "shiny film", I think hops, water issues, whatever. Usually the yeast won't have many new tricks after three weeks, though if you had a big temperature change or something that could be another matter, due to offgassing or some yeast activity or something like that.

If it is infected and you don't hate the taste, you can pasteurize to 170F, chill, repitch and prime (or don't repitch and keg). Some will say let it run its course, but good sours don't usually happen by accident.

 

[Smellyglove]

If you see a white/semi-white/semi-transparent MATTE film you most probably got some sort of infection. You can drink it for a couple of days, after that it will smell and taste "wrong". (It problably smells wrong already, but you can tap into it with a winethief and not notice it very much if if the surfac isn't way into becoming an alien planet).

 

[steev]

It doesn't smell.bad at all I just dry hopped a week ago and it smells the way I want but this white film has me paranoid now

 

[steev]

Really not too familiar with pasteurizing...should I boil it again and then repitch?

 

[steev]

After I repitch how long should I wait to bottle?

 

[steev]

I also don't have the best temp control its swings between 60-70 degrees during the day might this be the cause of the white film?...sorry for all these noob questions guys I'm new to this still and I just don't wanna have to dump the batch so of there's a way to save it please let me know

 

[fearwig]

Really not too familiar with pasteurizing...should I boil it again and then repitch?

Use a thermometer, and stir so your reading is good. Once it hits 170, it has been at pasteurization temps long enough, no need to boil. This is a last resort but doesn't seem to do much harm to flavor.

If you boil it, you may isomerize hop acids and make the beer more bitter than you probably want. This process starts around 180 and picks up rapidly as you go up from there.

After I repitch how long should I wait to bottle?

You can bottle right away, just mix the yeast in with the priming sugar once it's down to a safe pitching temperature. You don't need a lot of yeast, it doesn't have to do much work from here--but you should probably go with the same strain if you can.

I say >50% odds you don't have an infection. If you can take a pic, that would help. Hop oils from dry hopping can create a sort of sheen on top, and temperature swings can cause CO2 release which creates a little bit of foam or floats some yeast back to the top. These things could conceivably be mistaken for an infection.

Beer pellicles (google images)

 

[fearwig]

And for comparison, here's an example thread from someone who was worried about infection, but it turned out to be OK:

https://www.homebrewtalk.com/f163/infection-146585/

 

[steev]

Mine looks really similar to that picture hopefully its just some hop oils. When I moved it around a little the film gathers on the edges and clumps up

 

[eastoak]

Mine looks really similar to that picture hopefully its just some hop oils. When I moved it around a little the film gathers on the edges and clumps up

you wouldn't happen to have a cell phone that takes pictures? that would take lots of guessing out of the way.

 

[eastoak]

Infections rarely start in the primary because the organisms that can infect beer don't like the alcohol, the acidity, or are aerobic and the CO2 layer present in the primary stops them cold.

this is not a very precise description of what souring bugs can do. they will sour a beer in the presence of alcohol, acidity, CO2, and O2.