Wine’s Greatest Enemy: Light

Buying a bottle of wine out of a store rack or a cold case illuminated by fluorescent light may be worse than buying that same bottle from its cardboard box--even if it has been stored at room temperature.

“Lightstruck” wines are a major problem--but one that is rarely spoken about outside of winery laboratories. These are bottles that offer no ultraviolet (UV) protection and have been exposed to sunlight or fluorescent light for even short amounts of time.

One reason beer has traditionally been bottled in brown glass bottles is that beer is sensitive to light and this so-called amber glass gives UV protection.

The wine industry, however, has tradition standing in its path. Wine has traditionally been bottled in green bottles, though some wines (including a number of sparkling wines) are bottled in clear glass (called “flint” by the industry). Most of these bottles offer no protection from UV light. The results can be staggering.

Wine makers who are concerned about this problem say that a bottle of wine stored in the sun or under a fluorescent light source can change the aroma of a wine radically, leaving it with a funny aroma and taste.

One wine maker who experimented recently to see the effects of lightstruck wine was John Thacher of Cuvaison in the Napa Valley.

“We took a bottle of Chardonnay from a fresh case and stuck it outside on a cool day,” said Thacher. “The bottle never got above 50 degrees all day. We left it there from 9 a.m. to 2 in the afternoon.

“Then we brought the wine back in and set up a tasting, with a bottle from the case and the bottle from outside. The whole staff tasted the wines independently, and there was absolutely no comparison: The one from outside had turned smokey, lost its fruit, had gotten a gunflint aroma.”

Chris Markell, wine maker for Piper-Sonoma Cellars, called the aroma of a lightstruck wine “kind of like plastic or styrene.”

Greg Fowler of Mumm Napa Valley said, “There is a reaction between the sun and the sulfur components (in wine) that create this aroma, and it ranges from rotting leaves to a skunk.” He said that Robert Leaute, brandy master for Remy Martin, refers to the lightstruck smell as that of rotting cabbage.

Linda Bisson, a researcher working with Dr. Ann Noble at the University of California at Davis on the problem of lightstruck wine, said there were “some distinctive plastic characteristics that came out (of her research), and one I got was a Cornnuts aroma.” A partial solution is on the way, however. The largest producer of wine bottles in the United States, Owens-Brockway Glass Container, a division of Owens-Illinois, responding to industry pressure, announced recently that it has begun to produce bottles that have a UV protector built into the glass.

An letter to Owens’ clients some weeks ago said that all bottles of the “Champagne Green” color will contain the UV protector. This is a color commonly used in the California wine industry for Chardonnay, Cabernet Sauvignon and other popular wines.

However, many producers of Sauvignon Blanc, White Zinfandel and other paler wines like to use the flint (clear) bottle, which offers little protection from ultraviolet light.

Allen Babin, manager of production planning for Owens’ West Coast operations, said the firm had not yet decided whether it would extend the UV protection to other colors of wine bottles.

Richard Arrowood, who was the founding wine maker at Chateau St. Jean in 1975, said he knew back then that light could be a major problem, so he chose to bottle all his Rieslings and Gewurztraminers, the most sensitive wines, in amber (brown), “because that is the lowest actinic glass you can get.” He said low-actinic glass is light-absorbing and protects the wine “even better than green.”

“(Lightstruck wine) was a concern to us back then, and we chose amber to keep the wines fresh and to give us an extra edge,” he said. But he noted that it was difficult for him to find a supply of amber wine bottles. Owens made none for wine. Eventually St. Jean bought amber bottles from Dome Glass in Canada.

Arrowood said the color called Antique, a kind of amber/green, offers protection from UV and he said a number of wine makers are looking at it.

Fowler at Mumm said a lot of research is being done now in France. “This is a major problem,” he said. “An hour of direct sunlight in a clear glass bottle can noticeably change the wine. One of the reasons Roederer Cristal is wrapped in yellow cellophane is that they believe that it protects the wine better.”

Fowler acknowledged that the best bottle color for wine is amber. “The beer people have known about this because of the fluorescent light in coolers,” he said. He added that the problem is worse with white wine and Champagne than with red wine because the tannin in red wine is a good protector.

Dawnine Dyer, wine maker at Domaine Chandon, said the problem is a major one for the consumer “because of the way we are marketing wine--by the glass. The bottle is opened and it sits out, often under a light.”

She said that wine dispensed out of a nitrogen dispensing machine may be affected by the light inside the machine. Domaine Chandon was so concerned about lightstruck wine that it sponsored research at UC Davis into the problem.

A researcher set wine bottles out under varying wattages of light and for varying lengths of time “and there were detectable reactions in as little as 20 minutes,” Dyer said.

After seeing this research she became much more wary of buying wine in retail shops. “If the only bottle I can see is standing up on a shelf,” she said, “I ask if they can get me a bottle out of the case in back.”

Wine of The Week

Christian Brothers Meloso Cream Sherry ($3.75)-- Cream Sherry is a lovely finish to a holiday meal and this reasonably priced wine is one of the best on the market. The rich aroma is nutty, round and smells of roasted pecans. The sweetness of the wine (it is, in fact, not terribly sweet) is offset by good acidity. The Christian Brothers brand (now owned by Heublein) makes a line of fine dessert wines, all priced at less than $4. These include two light Ports as well as an attractive dry Sherry, an excellent aperitif. Two other cream Sherries worth looking for: Gallo’s Livingston Cream and Weibel Cream Sherry.