UV Light During Fermentation

The most convenient place to keep my carboys is in a room that gets ample sunlight on a daily basis. They are never exposed to direct sunlight but I was just curious if anyone knew whether or not the ambient light is detrimental to the beer.

I haven't had any issues, but since I know light can negatively affect beer after fermentation, it stands to reason that it could do the same during fermentation.

So is ambient UV light an issue or only direct UV light?

Try to avoid light exposure, the way I figure it is why risk it... Just put a dark T-shirt over the carboy

Cover them.

old T-shirts work awesome, +1 for them.

I try to avoid both direct and indirect light. The cardboard boxes that the carboys come in also work well for blocking light (I just flip them over and cut a hole for the carboy neck/airlock).

I flip those boxes over, too, but I find they stand up just fine on the box lid flaps, so that I don't have to cut a whole for the airlock.


TL

explosivebeer said:

I haven't had any issues, but since I know light can negatively affect beer after fermentation, it stands to reason that it could do the same during fermentation.

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It's the hop oils that have a problem with light, so pre fermentation, post fermentation, doesn't matter, you need to protect it from light, especially sunlight or florescent lights.

Thanks for the information everyone. I suspected that was the case but just wanted to hear what other peoples' thoughts on it. I'll get them covered up one way or another.

I place a Large Black Trash Bag over the carboy. Primary and secondary both the the Bag treatment.

Last time I was at mom and stepdad's, my step-dad had his carboy sitting in the open living room. I woke up one morning to see the carboy with sunlight streaming through it like that scene in Raiders of the Lost Ark when Indy was in the Well of the Souls searching for the Ark. NOooooooooo! I rushed to find one his tshirts and found a hideous tiedye tshirt to put over it. He told me he does that a lot (leaves the primary in the living room). I told him I hope he likes skunky beer.

So now all of his brews get the tie-dye treatment too :fro:

Clothes for your carboys

I always use blow off tubes, instead of an airlock, and I use the old t-shirt method also. I start the shirt part way up the blow off tube, and then down around the carboy. Works great. This will become more and more important as the eco-nazis force us all to convert to fluorescent lighting.

Oh yeah, and don't try to move the carboy with the t-shirt on it... take it off first. Almost dropped a carboy doing that, only made that mistake once. Those things are slicker than a greased pig at the county fair, if you try to pick them up with the t-shirt still on.

I didn't realize fluorescent light was bad too. I have a big peace of cardboard I block the basement window with, and it keeps them in shadow from the fluorescent as well so I'm covered.

RLinNH said:

I place a Large Black Trash Bag over the carboy. Primary and secondary both the the Bag treatment.

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Me too ... I always cover carboys with black trashbags ...use and re-use.

SuperiorBrew said:

Clothes for your carboys

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That reminds me of "hats for bats" from Major League. Do you have trouble hitting curves?

My favorite part about a cardboard box is you can label, date and write notes right on it.

SuperiorBrew said:

Clothes for your carboys

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That looks like the fixins for a kahlua/nyquil night cap over there on the right...

mrkristofo said:

That looks like the fixins for a kahlua/nyquil night cap over there on the right...

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Why even bother brewing when you have such a delicious concoction readily available??

Thats SWMBO's junk.
I heard on the radio about some Purple Monster Cocktail, made with Nyquill that Britney Spears was drinking before her last little trip to the hospital.

What is the overall flavor effect of the UV light on the beer?

HCNate said:

What is the overall flavor effect of the UV light on the beer?

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From what I've read the photochemical reaction of hop oils + UV = the same exact chemical that comes out of a skunks ass.