Have you ever tasted wine that smells and tastes like “cooked cabbage and wet dog”? If so, you might have attributed the spoilage to heat or cork taint, which are both uppermost in our minds when we think of spoiled wine. But research asserts that light presents a bigger problem, particularly for white wine. When white wine, especially in a clear glass bottle, is exposed to ultra violet and visible light at the blue end of the spectrum, it can spoil within a few hours, a condition known as light-strike, which initiates chemical reactions that produce moldy aromas and flavors. The most likely culprit for this condition is fluorescent lighting in markets and wine shops.
Introduced by long-time wine club member John Juergens, Ph.D. in Pharamacology, this research was a big surprise for me. I rarely buy wine at stores and have never tasted a spoiled white wine that I can remember. Most of the wine that I taste or consume is extracted from the corrugated box, into which the winery has placed it. At a tasting in my office or at a formal tasting venue, the wine emerges from the box or a bottle carrier that a sales person might be using and is poured directly into glasses. The wine I sample at wineries is equally protected. And any wine that you receive from Celebrations Wine Club also quickly emerges from the case and is repackaged for club members, exposed to light for only several minutes. Normally, neither do restaurants and bars store wine around bright light. But if you buy wine from stores, beware of light-strike.
“To reduce waste and recycle more,” the Waste & Resoures Action Programme in the U.K., which is promoting the use of lighter-weight wine bottles among other measures, has done a series of studies to better advise the wine industry. According to one of its studies, light-strike is a problem and one that most wine producers are aware of. Apparently, red wine is rarely subjected to light-strike, because the tannins in red wine protect against the condition. On the other hand, white wine and rose` contain only slight amounts of tannin and are by far more vulnerable.
The color of the glass bottle is extremely important, according to the study. Brown is the most protective and blocks the ultra violet and blue range of light by as much as 90 percent. Possibly wine producers have deliberately avoided brown glass to distinguish themselves from beer producers, who bottle almost exclusively in brown glass. Green glass blocks just 50 percent of light and white glass only 10 percent. Thicker glass, even when clear, blocks more UV light than thinner glass, and bottles with less pronounced shoulders reflect more light.
Because clear glass is more valuable in terms of recycling, the Waste & Resources Action Programme is suggesting that glass producers add certain chemicals to clear bottles to block UV light. The agency is also advocating sleeves and coatings for bottles. But at this point, these measures would increase bottle costs and are unlikely to be adopted.
So regarding light-strike, the take-away is to avoid clear or green bottles of white wine on tops shelves that would be most exposed to light sources. You might also reach for the bottle in back of the first one on a shelf. And of course, avoid light contamination at home. Just when we think we know enough, oops…. There’s more.
The chemistry behind the cabbage smell
Light-strike is a photochemical reaction rather than a temperature problem, which is why it can happen to a bottle sitting in a cool, brightly lit room. Riboflavin, a vitamin present naturally in wine, absorbs energy from light in the ultraviolet and blue-violet range and passes it along to sulfur-containing compounds. The products of that reaction are volatile sulfur compounds, and the human nose detects them at extremely low concentrations.
The wavelengths involved are the same short, energetic ones that concern people in other contexts. The Food and Drug Administration’s explanation of ultraviolet radiation describes how UV is divided by wavelength and why shorter wavelengths carry more energy. Glass color matters because tinted glass absorbs part of that range before it reaches the wine.
The compounds produced are the reason the fault is so recognizable. Volatile sulfur compounds are perceptible at concentrations measured in parts per trillion, so a very small chemical change is enough to dominate the aroma of an entire bottle. That sensitivity is also why the fault is described in such consistent terms by people tasting independently.
Tannin explains why red wine mostly escapes. Phenolic compounds act as antioxidants and absorb some of the incoming light, so a red wine has built-in protection that a white or rose largely lacks. That is a difference in composition, not in packaging.
Where wine is most at risk
Risk is a matter of exposure time multiplied by intensity, and the danger points are predictable once you know what to watch for.
| Situation | Risk level | Why |
|---|---|---|
| Sealed case in a dark room | Very low | No light reaches the glass at all |
| Wine rack away from windows | Low | Ambient light only, brief exposure |
| Top shelf under retail lighting | Elevated | Continuous exposure at close range, sometimes for months |
| Display in a sunlit window | High | Direct sunlight includes the full ultraviolet range |
| Kitchen counter beside a bright fixture | Moderate | Long exposure, often combined with heat |
What producers can do about it
The packaging decision is made long before a bottle reaches a store, and it involves a genuine trade-off. Darker glass protects the wine better, while clear glass shows off the color of a pale white or a rose, which is part of how those wines are sold. Producers who choose clear glass for that reason are trading protection for presentation.
Distribution adds its own exposure that nobody plans for. A bottle can sit in a lit display case, travel in a glass-fronted cooler and stand under retail lighting for months, and none of that appears anywhere on the label. The producer’s packaging choice is the only protection that travels with the wine.
Other measures exist and each carries a cost. Ultraviolet-absorbing additives in clear glass, printed sleeves, boxes and opaque cartons all reduce exposure, and all of them add expense per bottle or complicate recycling. The economics rather than the science are what keep most of them from becoming standard.
Practical habits for a household
A drinker cannot change how a store lights its shelves but can control almost everything that happens afterward. These habits cost nothing.
- Take bottles from the back of a shelf rather than the front, and skip anything sitting directly under a light fixture.
- Prefer darker glass for white wine and rose when the same wine is offered in more than one bottle.
- Store bottles in their original cardboard case, which is an effective and free light barrier.
- Keep wine out of direct sun, including on a covered porch where reflected light is stronger than it looks.
- Treat a decorative kitchen wine rack as short-term storage rather than a cellar.
Our notes on practical wine knowledge cover storage and faults more broadly, and the archive of hot topics collects the club’s other writing on how wine goes wrong between the winery and the glass.
FAQ: light-strike
Can a light-struck wine recover if I put it in the dark?
No. The reaction produces new compounds, and removing the light does not reverse them. Prevention is the only remedy.
Are modern store lights safer than older fluorescent tubes?
Generally yes, since typical light-emitting diode fixtures emit little ultraviolet compared with fluorescent tubes. Visible blue light still contributes, so proximity and duration continue to matter.
How quickly can the damage happen?
Research on the effect describes changes developing over hours of direct exposure rather than over months, which is why a sunlit display window is worse than a moderately lit room. Our guidance on serving wine with food covers the handling that comes after the bottle is safely home.