Do normal incandescent lights cause skunking?
Yes, the wavelengths generated by a standard incandescent fit within those that are known to "skunk" beer, a process that is a photochemical reaction that causes specific chemical bonds to change, resulting in flavenoids (flavors) that are generally distasteful. They emit about one third to one half of the intensity of sunlight in the <500 nm range that causes skunking. There are sunlight bulbs that emit about the same intensity as sunlight, so look at your bulbs to see. If they are marked "sunlight replacement" or something like that, keep your beer shaded. Even beer in brown bottles will skunk and some brews skunk more easily than others. Hope this helps.