Really, dude! What's your beer doing lying there on the ground ... in the sun?
In a beer exposed to sunlight's wavelenths, there will be photolysis of iso-alpha-acids in the presence of a thiol donor leading to 3-mehtyl-2-butenethiol. In other words, when sunlight hits the hops in your beer, your beer's going to smell like a scared skunk. And go down warm.
As seen —with a touch of photoshopping— at Blue Tarp Brewing, a small 'craft' brewery in Decatur, Georgia, on 6 August 2016, a 100-degree afternoon.
- Green glass is better than clear to forestall the skunky reaction, but not by much (e.g., that Heineken flavor). Brown glass is better yet, but still can't prevent it. In addition to visible sunlight, ultraviolet light, just like that in supermarket refrigerated beer cases, catalyzes the reaction. Cans, being opaque, prevent the problem altogether. Skunky is NOT stale: that's a different off-flavor, produced in old or over-warmed beer.
- More photos taken at Blue Tarp Brewing: here. The beers-on-draught were not skunky or stale!
- Pic(k) of the Week: one in a weekly series of photos, usually posted on Saturdays, and often, but not always, with a good fermentable as the subject. Camera: Olympus Pen E-PL1.
- Commercial reproduction requires explicit permission, as per Creative Commons.
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