Is light bulb light bad for fermenting?

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johnnyboy847

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Hi guys! I have a white, plastic fermenter which I have to use in a room with lights on most of the day. There are no windows so sunlight won't be a problem.

I've heared sunlight makes beer skunky, but what about light bulb light? And is this even an issue with a plastic fermenter bucket? You can see water level and krausen through it, so it doesn't block all the light.

Thanks!
 
Not sure if those buckets block UV or not...just dress it in a dark t-shirt and it should be fine.
 
Good question johnnyboy847, it would be great if anyone could chime in on incandescent light and Florescent too.

Cheers :mug:
 
As far as physics goes, incandescent bulbs match sunlight best. However, I've heard that fluorescent lights are worst for beer. No idea about intensity or exposure times.

Looking at it practically, I would think it is fine (imagine being in an identical, but larger bucket: you would never get a sunburn, so light is MOSTLY blocked). However, a dark t-shirt is pretty cheap insurance.


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http://m.livescience.com/33718-beer-skunks.html

Gives a technical but concise answer to the overall question.

As far as whether the bucket will protect it from the particular wavelengths I would say yes but like others have said a dark shirt is cheap insurance or a big cardboard box would work too.

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I use a lightbulb in my fermentation chamber as a heat source. It kicks on when the chamber needs to heat up. Never had any issue with skunking.
 
I use a lightbulb in my fermentation chamber as a heat source. It kicks on when the chamber needs to heat up. Never had any issue with skunking.

I use the light bulb in a paint can trick myself. I drilled a tiny hole in the bottom of my paint can so I have a visual indication of whether I need to change the light bulb any time the heat side is on. Never had any issues here.

I also make sure to point the light hole away from my fermenters as well. Don't know if this makes any difference or not.
 
I use the light bulb in a paint can trick myself. I drilled a tiny hole in the bottom of my paint can so I have a visual indication of whether I need to change the light bulb any time the heat side is on. Never had any issues here.

I also make sure to point the light hole away from my fermenters as well. Don't know if this makes any difference or not.

+1 on the paint can fermenter heater. A 40 or 60 watt bulb provides plenty of heat, but doesn't make the can uncomfortably hot.
 
I wonder how much this has to do with Kelvin or color temperature? I know that green glass filters to a wavelength that causes the skunking.

Sunlight has a typical color temp or 5500-6500K

Fluorescent cool white is around 5000K

Fluorescent warm white is around 3000K

Incandescent is around 2700K

Source: Wikipedia

Green glass may be concentrating the wavelength around 550nm. Fluorescent light and daylight has an energy peak in this area whereas incandescent peaks higher between 600-700nm.

With this said I would theorize that incandescent would be the least likely to produce skunking. Not certain what other reactions may be caused by incandescent vs. fermenting in total darkness absent of any light energy peaks.

PS: I always ferment in the dark. :cool:
 
Further: The light reacts with hops through photolysis. Photolysis breaks down the alpha acid constituents forming the compound 3-methyl-2-butene-1-thiol or skunk butt.
 
The light from a light bulb is magnitudes of less UV than direct sunlight. You can't really skunk a beer with a lightbulb unless you are trying to.

I have a glass front commercial cooler as a fermentation chamber, and the room I ferment in has it's share of nice direct sunlight. What I do is just put an old T-Shirt over the carboy while I ferment and bulk age. I have never had an issue with skunking, EVER!
 
I wonder how much this has to do with Kelvin or color temperature?

Sunlight has a typical color temp or 5500-6500K

Fluorescent cool white is around 5000K

Fluorescent warm white is around 3000K

Incandescent is around 2700K
Physicist here :)
This may be TMI, but I can shed some light on this.

So, the thing is that color only has a direct correlation to temperature when you're talking about "blackbody" radiation. Blackbody radiation refers to the glow that something has simply due to its temperature. For very hot objects, say about 2700 Kelvins, that glow can be in the visible spectrum that humans can see (hence the term "color temperature"). These are things like the heating elements on your electric stove, the filament in an incandescent light bulb, a hot piece of iron on a blacksmith's anvil, or the sun. Another important point about blackbody radiation is that it is always a CONTINUOUS spectrum. There are no gaps in the wavelengths of light that it emits. Let me illustrate:

tungstenlampsfigure1.jpg



Fluorescent bulbs are NOT blackbody sources. Fluorescent bulbs don't glow because of their temperature, they glow the same way a neon sign does: because of the direct electrical stimulation of gas and fluorescent atoms inside the bulb (fluorescent atoms absorb light and re-emit them in different wavelengths). They don't have a true color temperature, only an equivalent one that is meant to give you an idea of the color of light that it emits. Because it is NOT blackbody radiation and the light that it emits relies on the configuration of the electrons in the particular types of atoms in the bulb, the spectrum is NOT continuous:

spectrum-9-07a.png



To finally answer your question, the "skunking" of beer is caused by light breaking up a chemical compound from the hops, and that light will have to have a certain minimum wavelength to do the breaking. If you know that wavelength, color temperature can indeed predict how much effect the light would have on it since it is very easy to find how much light it will emit at that wavelength; every blackbody object at a particular temperature has the same spectrum. However, that ONLY works for blackbody sources, NOT fluorescent lights, since those lights spectra are not necessarily tied to their color temperature. To know if a fluorescent source would cause skunking, you'd have to find the wavelengths that the specific bulb emits, which is not knowable simply by its color.


I know that green glass filters to a wavelength that causes the skunking.

According to this source, clear and green glass do not prevent skunking, only brown does.
 
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