Beer and Light

Is it only direct sunlight that will skunk beer? I have my primary in a bathtub downstairs that has an opaque window up high which lets some light into the bathroom, but nothing direct to the carboy. Sooo... is this okay? Or will any daylight in a room, even indirect, skunk the beer?

your brew is not a roll of film. it sounds like your bathroom is just fine. just close the shower curtain/door.

for future reference its the UV light that skunks beer not normal visible light.

Brett3rThanU said:

Is it only direct sunlight that will skunk beer? I have my primary in a bathtub downstairs that has an opaque window up high which lets some light into the bathroom, but nothing direct to the carboy. Sooo... is this okay? Or will any daylight in a room, even indirect, skunk the beer?

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Four factors.

1. UV light in a certain range of wavelength (google for specifics). Sunlight has a lot, fluorescent light has less, incandescent light has less.

2. Riboflavin, your beer has some nothing to do about that

3. Isohumulone, unless you use tetra hop extract you have this two

4. Ability of light to penetrate beer. Not only will a t-shirt (or brown bottle) block UV light, so will a dark beer. Dark beers just do not skunk. If you have a pale beer I would keep it out of light period, just to play it safe.

I'm pretty sure that dark beers are also subject to UV damage, albeit less easily.

Play it safe and always protect the brew from UV light. If it's not in a keg I've got it covered.

Also Isohumulones will actually help protect your beer. Hops are a preservative and they will help, but not prevent, with a bunch of issues. Some commercial brewers even use concentrated hop extracts to help stabilize beer.

why would dark beer skunk less? Maybe because theyre traditionally less hoppy? I would think the darker beer would absorb MORE light.

doctorRobert said:

why would dark beer skunk less? Maybe because theyre traditionally less hoppy? I would think the darker beer would absorb MORE light.

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No, not really. Dark beer is opaque, so light is only hitting part of it and not the bulk. The same reason why UV light won't pass through a brown bottle. Light colored beers allow light to pass through the entire mass, whether in a bottle or carboy.

I know this may sound silly but I have a a few woven blankets that I wrap around my glass carboy and one goes over my bottle cases as well.
Help hurt or does not much? I have no Idea but I do know that there are threads here that talk about "Light struck beer" and it can happen in direct sunlight in under 1 min.