HDPE Fermenters and sunlight

[eastbaybrewer]

I was wondering if the HDPE fermenter block out the harmful uv light. I have a beer fermenting now and just noticed a some amount of sunlight hitting the fermenter. I have it covered now.

 

[bucketnative]

https://www.researchgate.net/public...ity_Polyethylene_in_Protection_of_Milk_Flavor
According to the above paper, HDPE does allow transmission of light in the UV range, more so than PET fermenters (which still allow some UV light). It's best to keep you fermenter shielded from light anyways. Sunlight might also cause higher temperatures than intended.