I build a fermentation chamber that has a small computer fan that is equipped with tiny blue led lights. Is it only UV light that can skunk a beer? What would the effect of this frequently run fan light be?

  • Why did you put a fan? Fansj ust move air they do not lower the temperature (unless you are moving in significantly cooler air)
    – Paolo
    Apr 30, 2013 at 8:00
  • In my chest freezer, I was having issues with even temperatures. One side would get colder (10degF) than the other, depending on where the temp probe was at. After installing two fans into it, the temperature stays consistent on both sides of the freezer. I use it as a kegerator, and the difference was causing minor issues with freezing, which is unacceptable when you want to serve beer from a tap (and fermentation)!
    – jsmith
    May 2, 2013 at 18:50

1 Answer 1


Here is some great information about beer skunking based upon wavelengths of light (http://www.safespectrum.com/applications_beer_wine.php). UV is the strongest light source that will cause beer skunking. However visible light, specifically anything under 500nm or thereabouts, are threats for beer skunking. And from this page (http://www.oksolar.com/led/led_color_chart.htm) you can see that blue light emitting diodes (LEDs) have their wavelengths under 500nms (470 or 420nms). Thus the blue lights on the fan could be a problem, but based upon the exposure time and brightness of the lights will determine the effect on the beer. Pale colored beers and very hoppy beers will have the most dramatic effect if there is an effect.

Why don't you just replace the fan with the lights with a normal fan, or place the computer on the outside of the fermenter. Also aren't you worried about the heat production by the computer? Or the possibility of the fermenter blowing off and ruining your computer? Seems like it would be prudent to place the computer on the outside.

  • 1
    I don't think there's an actual computer involved, just computer fan parts, hooked directly to their own power. I do the same to keep the components in my TV stand cool. Apr 29, 2013 at 18:59
  • Oh ok that would make sense. In that case the fan should be replaced with a non-light up fan. The effect may be negligible on the beer but it is definitely in the range of skunking light. For a beer in direct sunlight skunking takes a matter of minutes. But if the beer sits with very little light for a long time (days) this could have an effect on the beer. Apr 30, 2013 at 14:07

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