Any light or just sunlight bad?

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aliu630

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Hey guys

Quick question. Is any light bad for fermentation or is it just sunlight? I like to turn on my closet light to take a peek at my apfelwein when it's fermenting :cross: but I don't know if the closet light will mess up the fermentation? Should I stop doing this?
 
Apfelwein will not be light sensitive. Its the hops oil in beer that react to all light.
Go ahead

take a peek.;)
 
Awesome! Thanks for the quick response. Something about the fermentation process is fun to watch
 
Your not kidding when I first started me and my buddy propably watch most of our first beer ferment.
 
Wow I'm glad I'm not the only one who does this. Sometimes, with plastic fermentation buckets, I'll even press down on the top to force out a good whiff. The CO2 and alcohol fumes burn so good.
 
For future reference - if you're fermenting something that is hopped, any light can be bad for it. I never worry about that though...
 
Additionally, a LITTLE bit of light exposure isn't going to hurt anything. If you need light for a task or two in the closet - no problem.
 
I put old t-shirts over my carboys, with the neck of the carboy sticking up out of the neck of the shirt. I use a one inch blow off tube, running out to a bucket of water, and I wrap the shirt up and around the first part of the blow off tube. The seals out as much light as I possibly can.

As to sniffing, I too am guilty of stopping take a whiff of the blow off bucket. Hmmm.... hoppy yeasty goodness...
 
Here is an clip from an article on the beer advocate...it speaks to bottled beer but it should still apply.

Alström Bros said:
What does light-struck mean?
This is when the beer has been exposed to ultraviolet light for a period of time. Hop-derived molecules, called isohumulones, are basically ripped apart. Some of these parts bind with sulfur atoms to create that “skunk” character, which is similar in character to a skunk's natural defense and is such a potent compound that parts-per-trillion can be detected and even ruin a beer. Although brown bottles aid in protecting beer from being light-struck, it hardly makes the beer invincible. Green or clear bottles provide little to no protection. And it's been said that bottled beer can become light-struck in less than one minute in bright sun, after a few hours in diffuse daylight, and in a few days under normal fluorescent lighting.
 
I've heard that green lights will not react with the hops. Never tried it, no proof...
If it really is the UV light that causes the reaction, hypothetically you could use a UV filter.
Why bother? Well, if you had a "cold room" setup that you lagered in, fermented in, stored ingredients and stored beer in, you could have a light source that would cause no risk of skunking you beers. Of course, you could just cover everything, but that would oppose the efficiency of the cooler.
 
I've always understood that it is the UV that does the damage. Of course full sunlight would be the worst. From what I understand, flourescent lights can also crank out the UV also- People will use flourescent lights for inexpensive artificial greenhouses.
 
So does the hop oil only react when it is in beer, or will hops or hop pellets by themselves react to light? I am sitting here brewing with bags of hop pellets sitting on the counter, and the sun shining through the windows.
 
So does the hop oil only react when it is in beer, or will hops or hop pellets by themselves react to light? I am sitting here brewing with bags of hop pellets sitting on the counter, and the sun shining through the windows.

It is actually the isomerized alpha acids that react with the light and since you need to boil the hops to isomerize the alpha acids, your pellets will not skunk
 
So does the hop oil only react when it is in beer, or will hops or hop pellets by themselves react to light? I am sitting here brewing with bags of hop pellets sitting on the counter, and the sun shining through the windows.

your pellets are fine, its after the boil. it took sunshine to grow them :)
 
It's definitely just UV or fluorescent, right? Please? I'm doing my first batch with my new freezer fermentation chamber, using an incandescent light for heat. I read here a few places that incandescent was ok. Hoping I didn't skunk this one!
 
yes, ultraviolet or blue wavelenghts produced by sun or florecent light. your fine
 
Cool. Because aside from some wonky temps due to not pre-heating my mash cooler, this batch has gone perfect. Wouldn't want to wreck it by accident.
 
in general anything that emits uv light is bad but to be safe you should just keep it in the dark
 
The light from fluorescent bulbs are much more harmful to the beer than incandescent light. I have just a 25 watt bulb on a pullchain in the area near the carboys, and I only turn it on when I need to. No CFL bulbs in the brewery!
 
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