Marketing guru Seth's Godin gives his treatise on authenticity with a cool coffee drinking bell curve illustration.
I would add that people's need for authenticity is relative to the person and the product. For example, I'm not much of a coffee nut so I don't really care how authentic the coffee experience is, as long as I can get a cup when I need it. On the other hand, I am much more picky about my beers, what they look like, taste like and where I drink them.
There is a generational difference too. My generation (Gen X) and those after me tend to look for authenticity everywhere, even in the brands we buy. Maybe it is from being marketed to our whole lives, but younger generations tend to be much more sensitive to authentic marketing.
As usual the task falls on the marketer to determine what the audience is looking for and deliver the goods the way they like it.