View Full Version : Darkenss and metal with wines / meads

08-08-2010, 12:45 PM
When the wine / mead is in the 2nd fermenter. Is it OK to keep it at ambient room light, out of the sun? Or does it have to be in total darkness?

What about stainless steel and wine / mead?

I read that metals will mess up wines. Is using a stainless funnel or spoon to stir it going to hurt?


Medsen Fey
08-08-2010, 01:08 PM
Stainless steel is the ideal material for wine storage (aside from oak) and will not hurt wine. I keep most of my meads stored in Cornelius kegs made from stainless.

If you keep you carboys exposed to light (especially fluorescent) they can develop sulfur odors. If you wrap them with a towel, or put a T-shirt over the carboy, it will prevent such issues.

08-08-2010, 01:49 PM
Stainless steel is great for storage! There are other metals you could use, but they are all more expensive, like various titanium alloys, some of the nickel superalloys, some high chromium alloys, etc. Metals you should probably avoid include leaded brass and plain steels. For long-term storage, avoid dissimilar metals in contact with each other (e.g. a brass valve in a steel container). Aluminum gets a bad rap, but is fine for short contact. I'd not use it for prolonged contact unless it was anodized, however.

Ambient (reflected) light is not nearly as bad as direct or fluorescent light. However, it's easy to get a shirt, cardboard box, etc to throw on top of the carboy to keep it dark.

08-09-2010, 11:04 AM
Hmmmm? Where is the sulfer going to come from?

With beer, it's the hops that change into "skunk" in the presense of UV light. I had not heard of mead or wine having this problem.

About the only thing I know of is the color will fade sooner in light. Then again, I don't know anyone who stores in direct light!

Medsen Fey
08-09-2010, 11:16 AM
In wine it is know as Goûts de lumière, the "taste of light." It is caused by UV light interacting with sulfur containing amino acids. For some detailed description (and the references), see this info from the AWRI (http://www.awri.com.au/industry_support/winemaking_resources/frequently_asked_questions/notes/TN09.pdf). According to the Aussie's summary:

Maujean and Seguin (1983) demonstrated that ‘lightstruck’ flavour (goûts de lumière) is due to the formation of volatile sulfur compounds, which are believed to be derived from the sulfur-containing amino acids, methionine and cysteine. Riboflavin (vitamin B2), which is present in low levels in musts and wines, undergoes photo-activation and subsequent reduction when exposed to light at wavelengths of 370 nm and 440 nm. The sulfur-containing amino acids may in turn be oxidised, and subsequent reactions result in the formation of the sulfur compounds responsible for the sensory off character.