Why do red wines tend to be stored in green bottles and white wines not?

I was told that....wine in a brown bottle meant it was bottled in the autumn; and wine that was bottled in the spring is in a green bottle.

I'm a designer specialising in wine packaging and I can say that, with the exception of 'great' wines, most decisions about glass are made on purely aesthetic or economic grounds.

Great wines that are always aged for long periods are stored in green or brown glass to limit the damage caused by light over time. Wines like the Grand Crus of Bordeaux which are predominantly red, the great whites (and reds) of Burgundy, Champagne, the reds of Rioja Reserva and Gran Reserva, the great red wines of Tuscany, and the humungous Cabernets and Merlots of California. These are vintage wines which will live in their bottles for anything from between 5 and upwards of 50 years. Even though these wines are normally stored in wooden cases in dark cellars or temperature controlled warehouses, light damage over these long periods is a real possibility, hence the darkened glass. Of course, given the traditional nature of the product, traditional packaging is expected by the consumer, even though modern wine bottles can be coated with a UV filter so dark glass is now less relevant.

Wines which will be drunk quickly, in a year or two after harvest have no need of UV protection. You will still see whites in green glass, especially from 'classic' wine regions, and you will also see occasionally reds in clear glass, though in this latter case the glass will have probably been UV treated as even, though such wines will be drunk young, they will likely sit in full light on supermarket shelves for a while.

Light destroys wine. Simple as that. White wine doesn't last long anyway, so light doesn't get a chance to do much harm, red wine is harder to ruin but we also keep it longer. The way it happens is that UV sunlight actually causes a chemical reaction in the wine which ruins its taste.

Nowadays a lot of bottle manufacturers also make UVAG bottles. Generally, the darker the bottle, the better. Even though a red wine's tanins protect it from sunlight, because we tend to store red wine much longer, it is vital to protect it, especially from UV rays. The second best choice (after UVAG) is the brownish bottles, which are actually better than green.

The flavour of Red Wines deteriorates greatly due to the breakdown of the wine in the bottle when exposed to UV light. White wines don't have this problem as much as they are much more filtered and do not contain tannens, etc that break down this way. That's my understanding at least, I read something along these lines in the book "Making Good Wine" (ISBN: 9781405036016).

A quick google found a very technical study performed - and I'm sure there's a lot more supporting material than this! http://www.wrap.org.uk/downloads/UV_wine_quality_May_08.8a4c4eb0.5388.pdf

It's a combination of marketing and tradition. For better or worse you're average consumer expects white wine to come in a clear bottle.

This is not exclusive however, one example being Riesling which is traditionally bottled in brown glass.

Both white and red wine will change when exposed to light (Google "light struck wine" for plenty of interesting reading) but generally this is not as big an issue for white wine as it is usually drunk fairly young and stored cold.

The commonly repeated belief is that green bottles are better at keeping sunlight out and whites don't need this because they are often refrigerated. I never put much stock into this since worldwide refrigeration was not always common and a most wine is stored out of sunlight anyway.

A few winemakers in Sonoma told me that it was tradition based on the reasoning that reds were stored in darker bottles to hide the natural sediment that came along with those styles.

I don't know which, or if either, is true, but I'll tend to believe the tradition story over the UV-blocking reason.