In response to previous installments one and two, an Actual Scientist writes to set us straight about what really happens to precious droplets of beer when they are housed in amber-colored glass bottles as opposed to metal cans:
Sure, cans will keep out light better than bottles. But I want to correct something one of your readers wrote regarding ultraviolet light getting through amber bottles. The reason for the amber coloration is that it allows longer-wavelength, low-energy light to pass through, but blocks the high-energy photons including virtually all of the UV. Here's one spectrum I could find online, here. (My students would look at me funny if I walked into the lab with empty beer bottles to take their spectra.)
Amber glass transmits some visible light, so yes you can still see the beer--and since beer has some color, it does absorb some visible light and in principle this can trigger some reactions. But it's UV light that does some serious photochemistry, and if your beer is in an amber bottle, you don't need to worry about UV. (You can neglect that tiny hump around 340 nm.) I would expect that the difference between amber glass and aluminum cans is minimal as far as photodegradation is concerned.
So there. Granted, this chart is from a company that makes protective glass, but at face value it suggests that no UV light at all makes its way through amber glass. I will turn to my bottles of Lagunitas or Victory or Sierra Nevada or [name your brown-bottle-using brewery] with hope and trust restored.
Further on the trail of error, a veteran of the beer industry writes to chastise not me but one of the readers I quoted.
Your post admitting a wrong opinion of beer cans contained the following quote from a reader:
>>As someone in Colorado put it, "New Belgium Brewing in Ft. Collins has their flagship brew "Fat Tire" available in cans as well as their "Ranger IPA" [JF: I have had this, and it's great] and "Sunshine Wheat". Great for traveling. And don't forget, ALL draft beer is packaged in aluminum kegs." <<
I work for a beer distributor and can assure you that beer kegs are not aluminum. The industry standard is steel, although some craft breweries have turned to plastic to cut costs. I'm not aware of any beer kegs made of aluminum. Steel is used for its durability. Most kegs remain in circulation for many, many years.
Now, back to self-criticism as it applies to me. I mentioned yesterday that can-protected Dale's Pale Ale, of Colorado, had been in the "top ten" of a NYT tasting panel, rather than "winning" it, as a loyalist reader in Colorado had claimed. And in the most recent testing I was talking about, from 2010, that was indeed true. But the reader has come back to point out that in an earlier taste-test, in 2005, DPA had been the NYT's winner. So we're all right. And just as we still address George H.W. Bush and Jimmy Carter as "Mister President," even though someone else later got more votes than they did, so too can we refer to Dale's Pale Ale as a "national champion" beer, as at least once in its career it has been.
