Effect of light on fermentation/aging

[garbagegeezer]

Hello all.

I have a question that came up today when I was wondering whether my yeasties were starting to work away in their 5 gal white plastic "Ale Pail" home. I could not see them, and too early for bubbles. However, I have greater confidence in yeast activity when I can see the must in my 3 gal clear better bottle.

Can anyone relate to me the rundown on clear VS. non-clear fermenters? I guess this also brings up the issue of translucence of the secondary vessel and bottles (brown, green, clear, opaque) as well as whether the aging room should be dark or not (and how dark).

A quick google source uncovered the following abstract:

Light effects in yeast: inhibition by visible light of growth and transport in Saccharomyces cerevisiae grown at low temperatures.
J R Woodward, V P Cirillo, and L N Edmunds, Jr
Small right arrow pointing to: This article has been cited by other articles in PMC.
Abstract
Growth rate, sugar transport, and amino acid transport of yeast cells grown at 12 degrees C were inhibited by cool-white fluorescent light. At light intensities below 1,250 lx, growth and membrane transport were only slightly inhibited. Above 1,250 lx, there was increasing inhibition of both processes. Transport of histidine was completely inhibited after 3 to 5 days in cultures grown at 12 degrees C under 3,500-lx illumination. Cells grown at 20 degrees C were not inhibited by light intensities that caused complete loss of viability and membrane transport activity in cells grown at 12 degrees C.
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It seems like there study at room temp did not show any adverse affects.

 

[MikeBlick]

My understanding is that it can make the color of the wine fade. Although, i've made some apfelwein that got about half an hour of sun a day through a window and I can't tell a difference in taste or color from another batch I made at the same time which was in a dark closet. I'm actually drinking a glass from that batch right now...mmm mmm good.

That said, I try to keep my wine covered and out of the light.

 

[garbagegeezer]

I dug more into the forums and the light issue has come up in regards to skunking beer (hop oils reacting with photons to produce sulfur). There are no hops in my cider, but I wonder if when I use my clear better bottle the next time, I should find it a dark closet.

 

[SeamusMac]

I cover my carboy of Apfelwein with a black shirt, I'm not really sure if it puts me at any advantage but I do it anyways. Perhaps I like suspenseful event of pulling it off every weekend to see how well it has come along since I've been gone...?

 

[Homebrew-Micheal]

I started a cider recently using wine yeast pitched to no name apple juice. everything's going fine, I had about a half inch layer of foam at the top of my glass carboy for the first couple of days and it's died down since then. Today I turned the flashlight on my cell phone on and shined it into the carboy to see what I could see. Not much to be honest, but what I did notice was that a LOT of foam rose up from the must almost immediately after I put the light on it. At first I thought it must be from something else, but after a few more tests, I concluded that it was in fact the light causing the foam to rise from the fermenting must. My best theory is that some wavelength of light from my cell phone light is stimulating the yeast somehow, but I don't quite know how. Does anyone have a good explanation for this phenomenon?/

 

[Scrumpy!]

Bottled wine and wine in the anaerobic phase of fermentation (commonly refereed to as "secondary") can be ruined by exposure to light (so called "light struck"). Cider however does not appear to be affected by light. I ran across a reference to cider's immunity to being light struck but can't seem to find it now.