Why Does the Colour of Your Beer Bottle Matter?

Photo courtesy of Lighthouse Brewing.

If you’re a brewmaster making beer for the enjoyment of others, the ingredients and process you use are paramount. Quality control is one of the main concerns for beer drinkers who desire consistency with every pint. Regardless if you like Budweiser or not, no one debates that they have quality control mastered, as you always know how your beer will taste. One of the key factors in this consistency is the colour of their bottles.

The two biggest issues to affect your beer once bottled are light and temperature. Either of these can significantly affect the flavour of your beer, especially the former. This is why you see beer nerds cringe when they watch a beer commercial that shows open beer in the sun. Two seconds of direct sunlight will “burn” or “lightstruck” the beer, making it taste off. This is because light, especially ultra-violet (UV)  light, causes an instant reaction, changing the iso-α-acid to 3-methylbut-2-ene-1-thiol. If this sounds nasty, it is! The “thiol” change means sulphur. And even the smallest amount of sulphur, like one part per billion, will make your beer taste skunky.

This is why beer bottles are typically brown. They’re created specifically as a UV filter to protect your beer. Regular brown beer bottles don’t fully protect your beer, so you should still try to keep even a UV bottle our of the light.

Knowing what I’ve just explained, I’d suggest that any brewery using clear bottles is missing a huge step in ensuring the quality of their beer. It is why you may experience inconsistency of taste. You’ll also notice that these types of bottles often come from tropical places that need UV shading the most!

I like the trend going in the other direction. For example, Lighthouse Brewing’s Belgian Black has a powder coat of black on top of the amber glass that their brewmaster, Dean McLeod, informed me makes the bottle “…almost as lightproof as an aluminum can”. Rogue Ales offers their XS series in ceramic bottles, which are completely opaque. These are breweries committed to quality UV protection.

I have a hope that, some day, pubs and restaurants will start to understand and respect this. I envision a future where you’ll be on a patio enjoying the sun, and you’ll know you’re at a quality establishment when they bring you your beer with some type of shading device. In the meantime, I often open a menu 90 degrees to shade my beer. If asked, I use the opportunity to politely explain the reason to my server.

For more technical details, check out this Australian Brews News article. And remember, friends don’t let friends drink beer from clear, non-UV protected beer bottles.