Beer has often been packaged in glass bottles usually of either brown or green colour. Ever wondered why? Since the 19th century, brewers used glass material to maintain freshness. However, does choosing particularly brown and green coloured glass bottles random or hold a purpose? According to reports, the colour of the glass bottle plays a crucial role in preserving the taste and freshness of beer.
Brewers used to store beer in plain glass bottles, however, they soon realised that exposure to sunlight caused beer to lose its flavour. Overtime exposure to the sun rays leads to beer developing an unpleasant smell, due to the ‘lightstruck’. The phenomenon occurs when ultraviolet rays perforate the glass, it reacts with beer’s compounds, especially with hops which contain isohumulones. The exposure of isohumulones to UV light releases foul-smelling compounds.
In brown-coloured glass bottles, beer remains effectively shielded from UV rays, protecting its delicate compounds. Brown bottles are widely used as they prevent beer from losing its taste and smell. Breweries began using green bottles due to a shortage of brown glass bottles during World War II. Later, green bottles were commonly used in breweries despite them being more susceptible to the lightstruck effect. However, due to branding and tradition, the brewers continued to use green glass bottles along with brown bottles.
Nowadays, brewers have begun using transparent bottles which do not offer UV protection. The transparent bottles let customers have a better look at the beer. To maintain quality and visibility, the manufacturers use UV protective coatings to clear bottles. This way, beer remains fresh and away from light damage. After glass bottles, cans became widely used for commercial purposes. Cans provide 100 per cent UV protection and ensure beer’s freshness while minimising the lightstruck effect completely. In addition, cans are convenient for outdoor events.
