Seeing the Light?

Last week I noticed that Marstons Old Empire IPA was on special offer at Waitrose, in a three bottles for £5 deal. I've always been a fan of this 5.7% beer which claims to be faithful recreation of a 19th Century India Pale Ale, with its full-bodied, juicy malt base and its rich fruity hop character, as even if its authenticity might be called in question by some, it's still a damn fine beer.

One thing though always niggled me, and that was the beer was packaged in a clear glass bottle. The beer might look good in clear glass, and it's perhaps understandable that the marketing people might want to show it off, but as most people associated with the brewing industry know, clear glass allows the un-impeded passage of UV, and other wavelengths of radiation, which can have a disastrous effect on the beer. Beer exposed to ultraviolet and visible light is known as "Lightstruck", or "Skunked". Without going too much into the chemistry of the process, the light reacts with, and breaks down isohumulones, a molecule which is derived from hops that contributes to the bitterness of the beer. The resulting compound formed is very similar chemically, and in odour, to the musk-like mercaptans that are a skunk's natural defences; hence the term "skunked".

On this occasion I was pleased to see the beer packaged in a traditional brown bottle. The thought that Marston's may have had a change of heart crossed my mind, but the change of packaging was sufficient to persuade me to buy three bottles at this bargain price. I didn't think any more about this until I cracked a bottle open yesterday evening. The beer tasted good, but when I looked on the back  label I noticed a statement which read "MARSTON'S MARK OF QUALITY. All Marston's beers are bottled in Amber glass to avoid unnecessary deterioration sometimes experienced with clear bottles, ensuring the highest possible quality at all times."

Well they never used to be "bottled in Amber glass", but whilst this sounds like a taciturn acceptance of past mistakes, the change has to be applauded! If major brewers, such as Marston's have come out against clear glass, then there is hope at last that others will follow suit. The main culprits still using clear glass are Greene King, Shepherd Neame and of course Scottish & Newcastle, for their famous Brown Ale. Whether they too will change remains to be seen, but let's hope they see sense. the scientific evidence against clear glass is overwhelming. History too is in favour of brown glass, as it is not for nothing that over the last few hundred years beer has been packaged in dark brown bottles.

As a scientist I was so pleased with this about turn which, for a change, was a triumph of substance over style, that I felt obliged to write this blog post about it. Hopefully other writers and beer enthusiasts will spread the good news and encourage those remaining recalcitrants, who are still using clear glass, to do the same.