Cider and sunlight science?

[Freki]

I know sunlight can affect the hops and cause problems with beers, which got me to thinking, will sunlight harm a cider that is in secondary in a clear container? If so, what would it do?

 

[Grad]

I know sunlight can affect the hops and cause problems with beers, which got me to thinking, will sunlight harm a cider that is in secondary in a clear container? If so, what would it do?

Ya I wonder the same thing. I wrap a towel around the carboy if it's in direct sunlight just to be safe. I wouldn't worry about it if it is not in direct. I went to a wine making store once and they had dozens of wines in carboys that were fully exposed to the light so it's probably not a big deal. Though since beer is supposed to be kept out of light, I play it safe with a towel.

 

[RPh_Guy]

Sunlight causes heat.

Heat is bad for cider:
1. Heat causes faster oxidation reactions directly, AND thermal expansion & contraction introduces more oxygen through the airlock (and loss of sulfite, if applicable).
2. Heat encourages wild microbe growth.
3. Overheating may cause faster yeast death, leading to autolysis off-flavors, and additionally provide nutrients for wild microbes.

 

[dmtaylor]

Sunlight does heat up the cider, like a greenhouse-effect. That being said.......

If the temperature remains reasonably cool, less than like 75 F, I don't think it's hurting anything in a cider. Unless you've hopped your cider, in which case, you need to be slapped.

 

[Freki]

So it seems like I should be fine leaving them uncovered, as they would get a bit of ambient light, rather than direct sunlight. That was my main concern, and they remain in the proper temp range for my yeast.