If your beer smells like skunk...
The word that gets thrown around most for bad beer is probably “skunked,” which makes sense since there’s an incredibly high chance you’ve had one recently. How do you know you’re drinking a lightstruck beer? Pick up any beer sold in clear, green, or blue glass bottles, open it, and take a sip. It’s that easy!
This is because beer has three mortal enemies: oxygen, heat, and light. In the case of going lightstruck, the deterioration process begins almost immediately, and can be affected by any form of light, from the sun to fluorescent bulbs in a cooler case. Brown glass blocks over 99% of the wavelengths of light that will deteriorate a beer (and cans will block 100%), whereas others only get as good as around 30%. But if you stop to think about how popular certain well-known beers sold in clear or green glass bottles are, you’ll quickly realize that a lot of people actually like this defect.