Clear. Growlers. Why do they exist and why do they upset me?
If we look into the history of beer bottles we see that since the 16th century brewers have been struggling to find affordable and effective methods of distributing single servings of beer.
While there is limited historical information about how each individual brewery packaged their brews, recorded commercial bottling didn’t hit the markets until the late 17th century. Porters and other high body beers had a tendency to be bottled in ceramic stoneware which were strong enough to hold the brew, but incredibly heavy for distribution. Glass came in a variety of colors; blue, brown and green since obtaining pure silica for glass blowing was nearly impossible in those days. Furthermore, hand blown glass bottles couldn’t hold the pressure of the CO2 like it’s ceramic counterpart. Bottled beer was an extravagant purchase and so it was mostly used for export. In 1879 screw top bottles were created as a light weight, cheap and reusable solution, and until the first World War, bottled beer continued to soar. Prohibition, of course, halted sales (to put it mildly). With the arrival of WW2, glass was highly taxed and hard to find. Reusing glass bottles was common for breweries hoping to receive empty bottles back from its drinker. Yet when the war was oven and soldiers came home – they returned to beer heaven with bottled and canned beer being extremely available to the population.
Yet after all these centuries of hard brewing, scientific experiments, bad beer, and improvements in beer science clear glass growlers still exist.
What are people thinking? It has been known for YEARS that clear bottles allow for UV and Visible light to pass through the glass and affect the beer, imparting an off-flavor called Lightstruck. You can experience this yourself! Step outside in the sun with a pint. Take a sip every five minutes and by the end of the pint your beer will taste funky. And wrong. And bad. We even nailed down the molecule that causes this: 3-methyl-2-butene-1-thiol or 3MBT. It looks like this:
This molecule is formed when light from the UV and visible spectrum (350-500nm) pass through the isohumulones (hop acids) in the beer. Brown glass blocks any light around and below 500nm. Blue glass blocks around the 450nm mark and green glass begins to block light 400nm. Clear glass doesn’t block anything. Every single UV and visible ray of light strikes that beer and destroys it.
Yes, yes. Corona has and probably will continue to use clear glass. It’s cheaper. The beer doesn’t have a ton of hops to convert to lightstruck, and it’s almost always taken with lime – in which the citric acid covers the aroma of lightstruck. So clear glass is used by Corona, but only because they can get away with it.
Don’t buy a clear growler it will ruin the beer you paid for. If you already have one re-purpose it for cider, white wine, soda or a coin collection jug. But let’s keep one thing straight:
Clear growlers are Not for Beer.