It's a bit long if you're not into brewing, so I'll highlight a few points.
McGovern has the view that many humans, if not all humans, are biologically adapted for drinking fermented beverages. He also thinks that some sort of fermented beverages were made in prehistoric North America and Australia. At least for North America, it's extremely likely there was at least a maize-based beer like Chicha.
As materials and remains of ancient peoples are analyzed with greater sophistication, he sees great potential for this field to expand.
In the United States, you can purchase some of these ancient recreations through a partnership between McGovern and Dogfish Head brewery, a popular microbrewery. It's likely these Ancient Ales are available in Europe through specialty vendors as well. [Dogfish Ancient Ales]