🍷 Light strike
Also known as: lightstruck, light-struck taste, lightstruck wine, goût de lumière, sunlight flavour, light taint
A wine fault in which light makes white and sparkling wine smell of cooked cabbage, onion or rotten egg; dark glass protects against it.
Light strike is spoilage of wine caused by bright light, which gives it an unpleasant smell. Light strike (also lightstruck, light-struck taste or goût de lumière) is a wine fault in which light makes white or sparkling wine smell of cooked cabbage, onion or rotten egg. The culprit is vitamin B2, riboflavin: light sets off a reaction that breaks sulfur-containing amino acids into smelly compounds.
The harm comes mostly from light at about 370–450 nm, the blue-violet end of the spectrum. Riboflavin catches it, and the amino acid methionine turns into methanethiol and dimethyl disulfide. The wine also loses its floral and fruity notes.
It happens fast. In one test, still white wine in green glass picked up the smell after 31 hours under fluorescent lamps, and sparkling wine after 18. In clear glass, about three and a half hours were enough. AWRI adds that sunshine in a shop window does more harm than ordinary electric light.
The fault lingers, too: researchers could still smell it a year after the light exposure. That is why white and sparkling wines go into dark bottles, and why at home they belong in a cupboard or box rather than on a sunny sill. A dark bottle is no cure-all, though, since in the sun it warms up, and warmth changes wine as well. Sparkling wines made by the traditional method are more exposed, because yeast sediment adds sulfur amino acids.
Heat works differently: at 30 °C a wine takes about a year to pick up off flavours, while light needs hours. In the lab, chestnut tannin, glutathione and sulfur dioxide all limited the fault in white wine, with tannin doing best. For the wider picture, see wine storage and trade, the page on glass for the bottle side, and storage temperature for the cold side.
Facts
| Main use | Prevents cooked-cabbage, onion and rotten-egg smells caused by light 2 |
|---|---|
| Duration | Clear glass: 3.3–3.4 hours; green glass: 18–31 hours before the fault appears 1 |
| House range | Harmful light is about 370–450 nm (blue-violet); dark glass blocks part of it 2 |
| Taste | Smells of cooked cabbage, onion, rotten egg; floral and fruity notes fade 2 |
How it connects to Wine
🍷 Light strike → kind of → 🏪 Wine storage and trade → kind of → 🍷 Wine
Links
- What affects it
- 🍷 Glass
- Part of
- 🏪 Wine storage and trade
Frequently asked questions
Why does white wine smell of cabbage after sitting in the light?
Light makes riboflavin react with sulfur amino acids, which produces methanethiol and dimethyl disulfide. These smell of cooked cabbage, onion or rotten egg. The harm comes mostly from light at 370–450 nm.
Is clear glass worse than green for wine?
Yes. In one AWRI-cited test, white wine in green glass picked up the fault after 18–31 hours of fluorescent light, but in clear glass it took only 3.3–3.4 hours.
Can wine in a shop window be spoiled by sunshine?
It can. AWRI notes that direct sunlight, as in a retail window display, harms wine more than electric lighting does.
How long does the smell last once it appears?
A long time. Researchers report that the fault was still perceived one year after exposure, so a spoiled bottle will not recover on its own.
Is it true that a dark bottle fully protects wine?
No. It blocks much of the light, but in sunshine it heats up, and heat changes colour and taste. Shade and steady temperature matter too.
Similar
🍷 Enoteca (wine library) · 🍷 Wine refrigerator · 🍷 Wine cellar
Sources
- AWRI. Technical Note TN09: The effects of heat and light on wine during storage
- Fracassetti D. et al. Light-Struck Taste in White Wine: Protective Role of Glutathione, Sulfur Dioxide and Hydrolysable Tannins (Università degli Studi di Milano; PubMed Central)