a mood ring....for your beer

The label on a Coors Light bottle turns blue when the beer is cold enough to drink. Wow.

I didn't know the average American beer drinker had a problem determining when a beer is cold (and if it really is an issue, perhaps that's a sign it's time to put the beer down and switch to coffee.) I always resorted to holding the beer in my hand and, based on what I felt, made a subjective judgement on the drinkability of the beer. So far that method hasn't failed me.

I wonder, what color does the label turn if the beer is happy?