Sierra Nevada Brewing Co. has never been a brewery known for theatrics. So its decision to trial Shred Beer Soda in selected gift shops in California and North Carolina should not be mistaken for a publicity stunt. It reads instead like something more deliberate: a controlled experiment in how far the boundaries of beer can be stretched before they become unhelpful. The product itself is less important than the setting in which it is being introduced. By restricting distribution to...