Sunlight, UV Light & Wine Storage

Ultraviolet light (UV light) can have some pretty dramatic effects on your wine. Some of these effects can be positive (like photosynthesis for example!); however, many of them are negative and can disrupt the quality of your wine in bottle. The positive side of UV light comes from before the grapes have been fermented into wine. Before bottling, wine grapes can be enhanced with UV light by intensifying their colour and developing aromatic compounds. Grapes can overripen, however, if they are exposed to too much UV light, which can result in the degradation of these same compounds and produce overly ripe, sweet aromas and too many sugars.

What happens to wine that has been bottled and placed in a storage space which is exposed to a great deal of UV light? How does sunlight hurt wine? What are the negative effects of UV rays or sunlight on your wine including premature aging, a change in flavour, aroma and mouth-feel.

UV Light and Premature Wine Maturation

It's not just our skin that doesn't like exposure to many UV rays! The ultraviolet rays from the sun are known to speed up the aging process when it comes to wine too. Consequently, if you expose your vintage bottles to too much sunlight, the bottles may prematurely age. Nothing is more frustrating than opening that bottle of wine you have been saving for a long time to discover that it has spoiled, regardless of the reason. 

The reason behind UV light and premature aging in wine are due to the light’s effects on the chemical balance in a bottle of wine. When a bottle of wine is exposed to too much light, the chemical reactions inside the bottle speed up, which ends up causing faster degradation of the wine and results in a glass of prematurely aged and spoiled wine.

UV light causes aroma and flavour changes

Not only will the wine smell bad if you still manage to get yourself to taste it, but you will also notice that it has a sour and foul flavor to it. If you have a bottle of wine that has been light struck, we strongly suggest that you toss it out as it cannot be restored to its previous condition and these smells and flavours indicate that the bottle has been spoiled.

A wine that is exposed to too much UV light can experience undesirable changes in flavour and taste. The technical term for this side effect is “light-struck.” When a wine is light-struck, the smell can be described as similar to cabbage, sulfur, wet dog, or even wet wool. This smell is overwhelming and incredibly off-putting and also unmistakeable. Even with a bottle of Mouton Rothschild and the strongest desire to ignore the problem, you'll be unable to take more than a sip; it's beyond foul!

UV light and changes in mouthfeel

How else does sunlight hurt wine? Well, with premature aging and changes in flavour also come changes in texture. If you drink a wine that was previously silky, you may notice that it has a grittier feeling after being exposed to too much UV light. The reason sunlight harms your wine concerning mouthfeel is also because of the chemical reactions being sped up.

Overall, it is best to store your wine in a dark and cool space. Try to avoid placing your wine in high-sunlit areas. This will reduce the amount of UV light it encounters and help it to remain fresher for longer.

How a Wine Fridge Helps Reduce UV Light

If you don’t have a dark room to store your wine in OR are looking to increase the amount of protection your bottles get from UV lights, a wine fridge is going to be your best bet. Most wine fridges are designed with the intention of keeping UV light away from your precious bottles. They come with either UV protected glass doors or completely dark, sealed doors where no sunlight can enter. Either version will protect your wine from harmful UV light but if sunlight is a particular concern for you then opt for a solid door.

Here are a few of our wine cabinets that are the very best at keeping out UV light.

Artevino Oxygen Eurocave OXG3T199NPDLike all the Artevino cabinets, the OXG3T199NPD comes with a winter system which allows it to be placed in a garage or outbuilding so it can operate at low ambient temperatures. The standard configuration OXG3T199NPD comes with a solid door, 6 universal beech wood shelves that can be used for display, storage or sliding shelves plus two wooden compartments. As all these units are bespoke and made to order, customers should use the chat facility if they'd like to swap the door or add more shelves.

Climadiff RESERVE 300XL: With solid door and an exterior made from anthracite coal grey sheet metal your wine will remain undisturbed in total darkness and away from harmful UV light. The Reserve 300XL comes with 4 fixed and 1 wooden sliding shelf, a charcoal filter to prevent bad odours and automatic humidity regulation. The technology inside the cooler is designed to most closely replicate the conditions in a traditional Chateau cellar to allow your wines to develop to their optimum flavour profile over the decades.

Other Tips for Keeping Your Wine out of Sunlight

So, what else can you do to protect your wine collection from harmful sunlight or UV light?

Choose a wine that comes in an amber or green bottle: Some producers will use translucent glass to bottle their wine in. Although this may be a good marketing tactic to show off the colour of your wine, it does not protect it from UV light. The best-coloured bottle to purchase in regard to UV light protection is amber. However, a green bottle is more popular. Green glass cuts the damage from UV light in half, so it’s better than a clear bottle but not as good as an amber one.

Store in a cellar: Storing your wine in a cellar is the second best spot (a wine fridge being the best). Wine cellars are usually cool, which is great for keeping your wine at the appropriate temperature. They also help to reduce sunlight exposure because, typically, wine cellars have small and very few, if any, windows.

Don’t store by windows: Okay, this one is pretty obvious. If you are trying to avoid UV light from attacking your wine, it’s probably wise not to store it by a window. If you are going to have a wine rack in your living space, opt for a room that gets the least amount of light. You are also going to want to avoid opening the curtains. However, it is imperative to take caution when storing wine in your garage. Fluctuations in temperature and humidity can damage a cork, and bugs and pollutants can contaminate it.

TL:DR

When it comes to protecting your wine collection, UV light is something to be concerned about. Make sure you protect your collection from the harmful effects of sunlight with any of our wine coolers or wine cabinets that all have UV resistant glass doors or solid doors. Look at our wine fridge selection to see how we can help you protect your wine from UV rays.

Sarah newton

Leave a comment

All comments are moderated before being published

Author - Sarah Newton

Sarah Newton has worked in the wine industry for two decades holding senior positions at some of the UK wine industry's leading brands. The MD of Coolersomm, Sarah is WSET certified and our lead wine buyer too.