Exposed beer lines - lightstruck?

[jipjanneke]

My question relates to come exposed beer lines leading from our serving keg manifold into the insulated python that takes all the lines under the floor to the taps.

These lines are all located inside a coolroom with twin fluorescent lights inside running 24 hours per day. Some of these lines run for a several feet long, and are also fitted with clear plastic fob protectors. Indeed, the lines running from each keg to the manifold are probably 3 feet long. So, there is quite a bit of beer exposed to the light.

I've just started wondering, is it possible that the beer in these lines may become lightstruck during the night (when the lights are on but there is no beer flowing)? Should I cover them up, even with a blanket in the short term, or put a motion sensor in the room so that the light is off during the night?

I haven't noticed any particularly undesirable flavours in the served beer at all, but maybe it's just a subtle taste that we could easily avoid.

All comments/opinions welcome.

[zbrew2k]

I would say no. Although your taste buds are the final judge of that. The light struck compounds are active at parts per billion. So they show up very easily. It probably wouldnt cost much to cover your lines up either. You could wind plastic tape around them as a cheap solution.

If you want to spend some money, these people have it all sussed out:

http://www.safespectrum.com/light.html

Apparently they make special lamps for display cases and the like.

"Volume 8, Number 2 of New Brewer (March-April 1991) mentions the
magic number on page 10 in an article by Owens-Brockway entitled
' The Right Glass':

"'The degeneration problem occurs most frequently in warehouses or
retail outlets where fluorescent lighting is the norm. While all light with the wavelength of 520 millimicrons has the potential to cause beer skunkiness, it is the ultra-violet (UV) portion of the light spectrum below 400 millimicrons that is the most harmful to beer in the shortest period of time. (See graph.) In fact, it can affect beer flavor in as little as 24 hours.'"

"The graph, which I obviously cannot reproduce, shows that amber glass transmits about 5% of the light below 400 nm (UV), green glass about 80%, and clear glass about 90%. Between 400 and 520 nm (green), amber glass climbs from 5% to 30%, green drops from 80% to
50% (at 450 nm, which is blue-green) and then climbs back to 80%, and clear glass stays around 90%."