This is the first in a series of articles where I focus on a different aspect wine storage. Today, I am writing to tell you about light strike, one of the most common, least understood, and easily preventable defects in wine. Just as the name implies, light strike occurs when a wine bottle is exposed to enough ultraviolet light that cause chemical reactions in the wine. The light breaks down sulfur compounds that create a cooked cabbage or wet dog aroma in the afflicted wine. Obviously, the best way to prevent of light strike is to keep wine out of direct light!

A fascinating report on light strike was published last year in Britain, examining the protective role of wine bottles. Tannins inhibit the harmful reactions, so white wines are particularly vulnerable, followed by rosé and then red wine. Shockingly, white wines in direct light can be damaged in a matter of hours! Many variables such as the angle of the incoming light, thickness of the glass, glass color, wine label placement, and the intensity of the light source all affect how long a wine can withstand light before light strike occurs.

Clear glass blocks only 10% of harmful UV rays, while green bottles filter out 50%, and astonishingly, brown or amber glass blocks upwards of 90%! Of course, nothing beats opaque. Quality producers have shunned the reduced carboon-footprint, and light-strike proof packaging options of boxed wine and aluminum bottles. Even though wine producers are aware of the dangers of light strike, they continue to bottle in glass because of aesthetics and marketing appeal. Clear glass allows the consumer to see the color of the wine, and frankly, helps sell wine.

Since bottled wines are usually shipped from producers to retailers in cardboard boxes, wines are most vulnerable to light damage in the retail environment. Wine shops are notorious for putting wines on brightly-lit displays, while grocery stores always use the brightest lights. If you must purchase wine from a retailer with questionable lighting, remember the following tips:

• Choose from the bottles that are stored underneath displays or shaded from light. In other words, don’t pick the bottle on the top shelf, or the top of the stack!
• Unless you know that the windows are tinted to block UV rays, avoid wines displayed in windows.
• Bottles with higher turnover will also be exposed for a shorter duration. This is where it pays to know your local wine retail staff. They can easily tell you what wines are flying off the shelves and which wines have lingered on the shelves.
• Aim for darker color glass bottles, amber is best, followed by green. Avoid clear glass bottles when possible. Large wine labels help as well.
• Red wines are safer bets than whites, as the tannins protect the wines.

When you get home, protect your wine by keeping your wine in the dark. Shopping wisely and keeping wines away from light are very simple precautions that will help you get the most out of your wine dollars!