Yeast & Light

[Tony]

Okay, what are the issues with yeast, as in a starter, and the effect light has on it.

Ive tried to find any info on whether light damages yeast or helps it propagate.

 

[Nwcw2001]

Alrighty!

After tiring research I have found that the only way light affects yeast is if it is under perfect conditions and is UV light of a certain level. So in short No. yeast is not affected by light only hops are. that is what gives the "skunk"


HTH

John

 

[El Pistolero]

After tiring research

Could you please post your tiring research? I'm sure you're 100% correct, but there are some here from MO who will need to be shown. I'd do it myself, but I'm already tired.

TIA

 

[Nwcw2001]

here ya go!

http://www.selah.k12.wa.us/MS/SciProj98/7TH/CARMELL/radiation.html#CONC

so in short if you don't want to read this, in essence it says that UV light speeds up fermentation. That is the only effect any light has on yeast.


HTH

John

 

[david_42]

Ah! High School science. Yeast is a fungus and has no ability to photosynthesize. I suspect the only thing the UV was doing is heating up the water.

 

[Genghis77]

Sunlight: Aid in the yeast growth at the expense of making the beer skunky from the effect on the hops.

 

[Tony]

So light on a yeast starter, ethr direct or indirect, is no problem then?

 

[El Pistolero]

So light on a yeast starter, ethr direct or indirect, is no problem then?

Light on an unhopped starter will have no effect, except with the caveat that if you've got a clear glass vessel setting in direct sunlight, the temp inside will rise pretty quickly...just like in a car with closed windows on a sunny day.

 

[Tony]

Light on an unhopped starter will have no effect, except with the caveat that if you've got a clear glass vessel setting in direct sunlight, the temp inside will rise pretty quickly...just like in a car with closed windows on a sunny day.

Point taken! I just wondered it starters on stirplates need to be in a light devoid area, rather than a naturally lit room. As far as direct sunlight, no I always have my starters out of direct sunlight. but just wondered about in direct lights.

 

[Johnwongfat]

Ah! High School science. Yeast is a fungus and has no ability to photosynthesize. I suspect the only thing the UV was doing is heating up the water.

I would have to agree. I think that the following, "reach the top of the test tubes first than the test tubes not under ultra-violet radiation.", shows that his methods may have been just the slightest bit flawed. I have a feeling his mind was somewhere besides his high school science project. As long as you don't hop your starter wort, and I have seen a few people suggest that very thing, you will not have to worry about skunky flavors.

 

[El Pistolero]

Point taken! I just wondered it starters on stirplates need to be in a light devoid area, rather than a naturally lit room. As far as direct sunlight, no I always have my starters out of direct sunlight. but just wondered about in direct lights.

I don't see any reason why a starter on a stirplate would need to be in the dark.

 

[Tony]

I had read somewhere where someone posted about "how we all know light is bad for yeast" and it struck me funny, as I never had heard that, and wanted to make sure this was some wivestale or something, and make sure I didnt miss something somewhere. Thank everyone!