What is lightstrike in wine and why is everyone talking about it?

Most of us will have rejected a wine because it was corked. But have you ever sent a bottle back because it tastes of light? Essi Avellan MW explains the increasingly topical issue of lightstrike

Words by Essi Avellan MW

Wine bottles

While the issues surrounding corked wine are largely well understood and accepted, even sommeliers in fine restaurants can often be unaware of the destructive effects of exposing wine to light. What the French know as goût de lumière we call lightstrike – and it is one of the most poorly recognised faults in the world of wine.

The problem is much more prevalent than one might imagine, and is, sadly, a rapidly increasing one, due largely to the trend for still and sparkling rosés to be packaged in clear glass bottles. The fashionable nude look that seems to increase the wine’s desirability and sales unfortunately also poses a huge risk to its quality. This, together with a concerted campaign by Champagne critics (this one included) has seen the issue suddenly thrust into a wider limelight, beyond its usual coterie of technically minded industry insiders.

The technical part first: the affliction is brought on when light reacts with riboflavin, which is naturally present in wine, and photo-oxidizes methionine (a sulphur-containing amino acid also present in wine) to form undesirable sulphur compounds such as dimethyl disulfide or DMDS. An hour’s exposure to the wrong sort of light is more than enough to produce these unpleasant sulphur compounds in a wine – cue aromas of cooked cabbage, rotten eggs, smelly cheese or even sewage. But it’s not only the nose that is spoiled, its fruity aromas at risk of being corrupted. Light can also affect the colour of a wine – and while white-coloured wines are the most vulnerable, rosés are at great risk too.

So what is “the wrong sort of light”? Generally we’re talking wavelengths below 510 nanometers, meaning ultraviolet and blue rays of light are particular culprits. Just five minutes in direct sunlight can do enough damage to be detected. Such an adverse effect can easily be spotted when sipping Champagne outside in the sun, where it very quickly develops a funky odour in the glass. The effect is irreversible.

Consumers looking to buy individual bottles or opened cases of wines in transparent glass containers need to take into consideration the wine’s entire storage history. Artificial lights such as fluorescent tube lighting can do significant harm to wine. When shopping at your local merchant, avoiding any exposed colourless bottles is often enough. Luckily, with the new generation of rosés, many come in giftboxes; they should be kept in them until the moment of consumption. In the same way, the coloured cellophane wrappings are placed around the bottles for protection, not decoration. Many are removed upon purchase, for storing or refrigerating, when it would be wise to keep them on – even when serving the wine.

The most historic and renowned of clear glass bottles is, of course, Louis Roederer’s Cristal Champagne, which received its transparent look in 1876 when it was first crafted for the Tsar Alexander II of Russia. When the wine was later recreated as the prestige cuvée of the house, the dangers inherent in clear glass bottles were taken into account. The solution was an orange-coloured cellophane wrapping, which is able to filter 98% of the harmful rays of light.

Louis Roederer Champagne
Louis Roederer’s Cristal Champagne is packaged in orange cellophane, which is able to filter 98% of harmful rays of light

It is fair to say that Cristal’s striking cellophane-decorated looks have been as effective in enhancing its desirability as in safeguarding its quality. Similar commercial clear-glass success stories include Ruinart’s non-vintage Blanc de Blancs, whose naked looks are just as appetising as its contents. It would be too risky, commercially, to change it, even if the winemaking department so wishes. Instead, Ruinart recently unveiled an innovative solution by developing an aesthetically appealing lightweight ‘second-skin’ to the bottles, crafted of sustainably produced recyclable carton.

Ruinart Blanc de Blancs wine
Ruinart Blanc de Blancs wine
Ruinart has developed an aesthetically appealing lightweight ‘second-skin’ for their bottles, crafted of sustainably produced recyclable carton

Responsible Champagne producers are taking the matter increasingly seriously – and rightly so. Traditional method sparkling wines that spend a long time on lees in reductive conditions are particularly vulnerable to the ravages of light. So why use them at all? English producer Nyetimber serves as an exemplary pioneer in rejecting them, having turned instead to very dark amber glass. And now Slovenian winery Radgonske Gorice is releasing its “Untouched by Light” sparkling wine which it claims is the world’s first sparkling wine made, sold and tasted in complete darkness –night-vision goggles being used for harvest, bottle rotation and packing, the wine housed in a black light-proof bottle, within a 100% recyclable vacuum-sealed bag, blocking any additional light or air contact.

Nyetimber sparkling wine
Two bottles of Nyetimber sparkling wine
English producer Nyetimber uses very dark amber glass for their sparkling wines

Conversely, led by the highly successful crop of Provence rosés, the vast majority of rosé producers are taking the issue regrettably lightly. Here, clear glass is the norm, as are the unprotected displays in supermarket aisles and wine shop windows. The choice of glass raises even more eyebrows when you stop to consider that rosé is a wine that is often consumed outside while enjoying the sunny weather.

Many producers seemingly think that as long as the wine has left the winery in proper condition they are liberated of responsibility. But this reasoning puts far too big a responsibility on retailers, restaurants and – most importantly – consumers, where the requisite level of understanding is simply too much to ask for. And why would producers take the risk of a consumer finding that their wine tastes “bad” without understanding that there is a fault in it?

As long as consumers continue to choose colourless bottles over dark ones, change is unlikely to happen. Instead, we need to leave unprotected bottles on the shelves and put quality first. It is simply senseless to let a moment in light ruin a wine the producer has spent years making and maturing. Not to mention a complete waste of money…