Sunlight will damage your wine

Most wine enthusiasts know that sunlight during the storage of wines is not a good thing, but few of us really understand why.

Why does sunlight damage wine?

Sunlight damages wine through a process known as photodegradation, which involves the interaction of light with the chemical compounds in wine. This process will usually lead to undesirable changes in the wine’s flavour, aroma, and overall quality.

How does sunlight damage wine?

Sunlight can damages wine in four ways, UV light damage, the creation of free radicals, oxidation of the wine and the breakdown of sulphur.

1. Ultraviolet (UV) Light Interaction

  • UV Light Exposure: Sunlight contains ultraviolet (UV) light, which is high-energy radiation that can penetrate the wine bottle, especially if the bottle is clear or lightly tinted.
  • Excitation of Molecules: UV light can excite certain molecules in the wine, particularly phenolic compounds (such as tannins and flavonoids), leading to chemical reactions.

2. Formation of Free Radicals

  • Radical Formation: When UV light excites these molecules, it can cause the formation of free radicals—highly reactive species with unpaired electrons.
  • Oxidative Reactions: Free radicals can react with other molecules in the wine, such as oxygen. This can initiate a chain reaction of oxidative processes.

3. Oxidation of Wine Components

  • Oxidation of Phenolics: The phenolic compounds in wine, which contribute to its color and flavor, can be oxidized, leading to the formation of quinones. Quinones can polymerize, causing a loss of color and changes in flavor.
  • Degradation of Aromatic Compounds: Aromatic compounds responsible for the wine’s bouquet can be degraded or transformed into unpleasant-smelling aldehydes and ketones.

4. Sulfur Compounds and Lightstruck Flavor

  • Lightstruck Flavor: One of the most notable effects of light exposure is the development of “lightstruck” flavor, which is particularly common in white and sparkling wines.
  • Sulfur Compounds: Light exposure can cause the breakdown of sulfur-containing compounds, such as thiols, leading to the production of undesirable sulfur compounds like hydrogen sulfide (H2S) and mercaptans.
  • Off-flavors: These sulfur compounds can impart off-flavors reminiscent of wet cardboard, cooked cabbage, or skunk, significantly diminishing the wine’s quality.

How to Prevent Sunlight damage to wine

  • Dark Bottles: Using dark-colored bottles (green or amber) can help filter out UV light and reduce the risk of photodegradation.
  • Storage Conditions: Storing wine in dark, cool environments minimizes exposure to both light and heat, further protecting it from photodegradation.
  • UV Filters: Some wine producers use UV filters in the glass to provide additional protection against UV light.

For more help and knowledge on the proper storage of wine, and protective measures please contact our team of experts: Tel: 0115 9441434