How much effect does light have on fermenting beer?

Question

How much effect does light have on fermenting beer?

Dmac the Destroyer

2021年1月27日 21:58

If I keep my fermenting beer in my living room, should I cover it with blankets or otherwise keep it out of the light? I've seen topics on brewing referencing this, but most just settle for "why take the chance?"

I'm hoping for a little more clarity on the matter.

Topic light fermentation homebrew

Category Mac

organic chemist · Accepted Answer · 2016年1月23日 01:34

1

organic chemist answered at 2016年1月23日 01:34

UV wavelengths do not penetrate glass. It is more likely that visible wavelengths catalyze photodegrading reactions of the dissolved organic carbon, the stuff leaching out of the hops included.

user12489 · Accepted Answer · 2015年8月2日 05:46

my 2 homebrew fermenters were getting about 30 to 40 minutes of direct sunlight at about 10 am every morning for about 6 to 7 days and the beer tastes terrible. I am now covering up my fermenters a will see how the next batch tastes.

805 ICK · Accepted Answer · 2014年4月13日 17:21

1

805 ICK answered at 2014年4月13日 17:21

You can wrap the whole fermentation carboy or bucket in a black plastic trash bag. It stops light and will contain any messy spills or explosions. Be sure to leave the bag open at the top so heat and gas can escape.

Ryan Sullivan · Accepted Answer · 2013年1月9日 04:32

I'm just down I-5 in Portland. I tend to use carboys for my fermentation vessels, so what I do is keep the box the carboy came in, cut a small hole in the bottom of the box, cut the top flaps off the box and make a sort of carboy sleeve that slips right back over the bottle and leaves the airlock sticking up from the small hole, so far it's worked fantastic.

Ryan Shdo · Accepted Answer · 2012年4月7日 05:05

I live close to Seattle (puyallup) and we get UV rays even when its cloudy. you could through a pillow case over it but that wont block all the UV's maybe a open top cardboard box (assuming you want easy access).

Ultraviolet light is often used to purify water because it kills bacteria. Yeast Is a fungus which essentially is a slightly more complicated organism, therefore it has a little more fighting power against it's enemies (UV). Yeast stress is of coarse a big issue in fermentation and anything you can do to keep them yeasties calm the better, UV stresses yeast.

Typical commercial "beer skunking" has nothing to do with yeast, It's more of a hop alfa acid thing... here is a great link http://www.washingtonpost.com/wp-dyn/content/article/2007/02/27/AR2007022700312.html

David PGB · Accepted Answer · 2012年3月16日 13:02

It's the hops that create that skunky aroma. The UV rays react with the hop oils and spoil. Also, if the fermentor is in direct sunlight, one would assume that the fermentations temperature would begin to rise until the sun sets, when the ferm temp would start to fall! Better to keep a constant temperature and keep out of the sun.

At the very least, cover with a blanket to protect your hops!

Ell · Accepted Answer · 2012年3月13日 17:06

Keep it out of the light.

ESPECIALLY if the fermentation vessel is clear, but generally, keep it out of the light.

Light (specifically, UV rays) will skunk the beer, producing off-flavors. It's probably better if you have a closet or someplace else out of the way that's dark to ferment.

But - keep it out of the light.

How much effect does light have on fermenting beer?

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