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Exposure to sunlight causes beer in transparent bottles to lose its flavour and develop an unpleasant smell. This phenomenon is known as ‘lightstruck’
Brown bottles are the most effective at shielding beer from UV rays, preventing chemical reactions from spoiling its flavour. (Getty Images)
Have you ever wondered why beer bottles are usually brown or green? These colours are not chosen randomly or for marketing purposes. Instead, they play a critical role in preserving the taste and freshness of beer by protecting it from sunlight.
Importance of The Beer Bottle’s Colour
According to a Times of India report, beer has been packaged in glass bottles since the 19th century because glass is an excellent material for maintaining freshness. However, brewers soon realised that plain glass bottles were unsuitable for storing beer. Exposure to sunlight caused beer in transparent bottles to lose its flavour and develop an unpleasant smell.
This phenomenon, known as ‘lightstruck’, occurs when ultraviolet (UV) rays penetrate the glass and react with the beer’s compounds, particularly hops. Hops contain isohumulones, which, when exposed to UV light, can release foul-smelling compounds.
Why Brown Bottles Are the Best
According to reports, brown bottles are the most effective at shielding beer from UV rays, preventing chemical reactions that can spoil its flavour. By blocking light, they protect the beer’s delicate compounds, ensuring its taste remains pure. Brown bottles became widely used as breweries sought to address the adverse effects of light on their products. Even today, brown bottles remain the most common choice in the beer industry.
The Introduction of Green Bottles
During World War II, a shortage of brown glass led breweries to adopt green bottles. Consumers began associating green bottles with premium-quality beer. However, green bottles do not offer the same UV protection as brown ones, meaning beer stored in green glass is more susceptible to lightstruck effects. Despite this, many breweries continue to use green bottles for branding and tradition.
Why Not Transparent Bottles?
Transparent bottles allow consumers to see the beer inside but offer no UV protection. This makes beer stored in plain glass vulnerable to light damage. To address this, some manufacturers now apply UV-protective coatings to clear bottles, balancing the risks while maintaining visibility.
Cans: A Modern Solution
Cans are really popular because they provide 100% UV protection, ensuring beer remains fresh and unaffected by sunlight. Along with this, cans cool quickly and are convenient for outdoor events.
