Summer has begun and with it the high temperatures. With this heat, the crave for drinking a good refreshing beer grows even more, and in that refreshing moment, when you look at the bottle, haven't you ever wondered why beer bottles are mainly dark, brown or green in colour?
Today, we will explain the scientific reason for this choice since it began to be bottled centuries after beer was first brewed in Mesopotamian cultures in 5000 BC.
As we discussed in our post on Beer expire date and sensorial changes over time, exposure to sunlight is partly responsible for the negative sensory changes in beer. Ultraviolet rays degrade hop components, generating sulphurous substances and creating unappetising aromas and flavours, also affecting the colour of the beer in particular.
In order to prevent this degradation by exposure to the sun, the experts decided to dye the glass brown, with a few exceptions in green, when brown glass was in short supply in view of the Second World War.
Brown bottles, a great ally of craft beers
Brown glass is capable of retaining up to 85% of ultraviolet rays and thus the negative effects on beer in the summer, when the sun gives no respite.
It is true that nowadays glass, regardless of its colour, has additional treatments to block the sun's rays, but some brands choose to continue to keep these colours for their corporate identity (They have 'hope' in their colour ;)).
Canning boom, craft beer cans on the rise
A great choice for craft brewers is the use of cans for bottling beer, leaving behind the metallic flavours of long ago thanks to nowadays’ new canning technology. The use of cans effectively protects the precious beer from its greatest enemies: light, heat and oxidation.
But we will talk about this in the future if you follow the most brewer blog.
Next time you’ll know what to talk about while sharing some bottles of craft beer with your friends!