Which type of packaging offers the least protection from skunking beer?

Green bottles offer the least protection from skunking beer primarily due to their transparency to light. Skunking occurs when beer is exposed to ultraviolet (UV) light, which interacts with the hops in beer and leads to the formation of off-flavors, commonly described as a skunky aroma.

Brown bottles provide better protection against UV light because they absorb a significant portion of the light spectrum that causes skunking. Cans, being opaque, offer complete protection from light, making them the best option in terms of preserving beer quality. Kegs also effectively protect beer from light exposure since they are usually stored in dark conditions and are not transparent.

In summary, green bottles allow more UV light to penetrate, increasing the risk of skunking and resulting in lower quality beer compared to the other packaging options listed. This makes them the least effective choice in preventing this undesirable effect.