Effects of light on secondary in a carboy

[joejoe]

I have a 5 gal. carboy of a California Common Lager that I brewed a few weeks ago sitting in my basement at 64 degrees. During primary fermentation it was covered with a big towel. During the past 10 days of its secondary fermentaion it has been in my basement uncovered at 64 degrees. Occassionaly one of my kids will forget to turn the light off in the back room so the beer is exposed to some light. Will the light from this 60 watt bulb it hurt the beer?
The beer has been exposed to perhaps a few hours of light per day for the past 5 days.
Are there signs of damage I should look for when I am ready to bottle?

Thanks for any advice on this.
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[Tweek]

If your beer became light struck it will taste of skunk. You will know it when you taste it for sure

[b3s]

i was led to believe that it was uv, not incandescent/fluorescent, light that was the culprit. am i wrong on that?

[joejoe]

I found this quote from John Palmer's book "How to Brew":

"The wavelengths of light that cause the skunky smell are the blue wavelengths and the ultraviolet. Brown glass bottles effectively screen out these wavelengths, but green bottles do not. Skunkiness will result in beers if the beer is left in direct sunlight or stored under fluorescent lights as in supermarkets."


So I assume I will be alright if the light that has been hitting my carboy comes from a regular light bulb.

This also begs the question: What about the last batch that I bottled in green Grolsch EZ cap bottles?

Will they be OK if they sit in the light?
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[batkins]

and what aout the blue ez-caps?

[paul84043]

I just try to avoid letting any of them sit in the light, period....It sure takes all the guesswork out of it.

If the damaging rays are UV, then the color of the bottle is only going to have a minimal filtering effect, no matter what color it is, some will simply let more visible light in than others. You've probably noticed that you can get a UV protective coating on a pair of glasses that doesn't change the perceived color at all, the lenses will still be clear. UV is invisible unless your'e a bird, or possibly a bee or butterfly...

I would venture a guess that the MOST damaging rays are UV, but that simple visible light in any form is also a no-no.

Brown is just a mish- mash of many of the colors in our spectrum, Obviously not all of them, otherwise it would be white..... so it filters out more light than a bottle that has a "primary" color, or a simple combined color like green (yellow and blue).

So....to review..Colored bottle, good....clear bottle, bad....darker bottle, better....no light and darker bottle....very good....drink beet faster than photons can reach it.....BEST!!!!