How much light do brown bottles block from penetrating the beer?

Brown bottles are highly effective at blocking light, particularly ultraviolet (UV) light, which is detrimental to beer quality as it can lead to the development of off-flavors, commonly known as "skunky" beer. The correct choice indicates that brown bottles block approximately 98% of UV light, significantly reducing the risk of light-related spoilage.

This high degree of protection makes brown bottles a preferred choice among brewers for packaging beer, as it helps in maintaining the beer's flavor stability and overall freshness during storage and transport. Comparatively, green and clear bottles offer much less protection from light, leading to a higher potential for light-struck defects in beers packaged in those types of bottles.