The Green Bottle Conundrum

The same Jester King announcement I referred to in my previous post has sparked quite a bit of controversy. Jester King, known for its farmhouse and funky beers, is going to use green bottles instead of the brown variety they thus far have been bottling their beers in. Or at least for one particular beer, they’re about to run an experiment by bottling it in green bottles and see what develops.

This use of green bottles received quite a lot of frowned eyebrows and concerns in the beer community. But why is this such a big deal ? What is the problem with using green bottles ?

It all has to do with keeping a beer as fresh as possible and as close as possible to what the brewer intended. In addition, people have adopted a tendency to cellar and age beers, much like wine aficionados tend to do. And thus it generates the challenge  to determine which container is the best one to make sure that as a beer ages it preserves all the good qualities and doesn’t develop any bad ones. And yes, beer can develop some nasty traits.

One of them is that beer is light sensitive. Or more accurately, the isohumulones in hops are light sensitive. The detailed chemical explanation is that the iso-α-acids break down and form 3-methyl-2-butene-1-thiol when exposed to UV light. This iso-α-acid is what gives beer its bitterness. The “thiol” in the resulting chemical compound indicates the presence of sulphur and it is most often associated with the smell a skunk leaves behind. Hence in the vernacular this process of beer developing this sulphury aroma is often called “skunking”. Mark that contrary to popular belief, this is not an off-flavor, but an odor that can disappear quite quickly after a beer is poured in the glass. I’ve had beers where the aroma lingers, but more often that not, it’s gone within minutes or even seconds of pouring the beer.

So what’s up with the green bottle ?

Green colored glass is less efficient in limiting the UV light that reaches the bottle beer. Hence the risk of a beer developing the skunky aroma is greater. On the other hand, one can argue that several Belgian beer styles are traditionally bottled in green bottles. Especially the lambic style beers from the Senne valley near Brussels are bottled in green bottles. And I have never heard anyone complain that a Cantillon, 3Fonteinen or Hanssens Artisanaal was “skunked”. When I serve one, usually people’s eyes glaze over, roll backwards in their heads and exclamations of appreciation follow after the first sip. Hype ? Or Truth ? Personally I have never experienced more than a faint skunked aroma in a lambic beer. This may be the result of the fact that the lambic beers are traditionally brewed with old hops containing very low levels of iso-α-acids. Since those same chemical compounds bring the preservative qualities of hops to the table, when making a beer that is naturally soured by bacteria and other micro-organisms, we want to avoid those preservative qualities. We want to introduce the bacteria to develop these sour flavors. Not stop them. So we want some of the hop aromas, but not the preservative qualities. Hence low levels of iso-α-acid and consequently low risk of UV light creating the dreaded skunk aromas.

So what about the Jester King approach ?

Most of the Jester King beers I have had the pleasure tasting exhibited likewise very low hop bitterness. On the other hand, two of the three beers they picked to bottle in green bottles are described as “well hopped” and “an abundance of noble hops” respectively. This may be the cause of some concern that undesirable aromas may develop. It works for the aforementioned lambic brewers exactly because of the absence of high bitterness levels. But perhaps it does work. Only time will tell. Personally, I look forward to getting my hands on a green bottle vs. a brown bottle version of the same beer and do a side-by-side comparison. Maybe they’re on to something. Or maybe, it’s nothing more than a good marketing scheme.