The archaeology of beer and other inebriants is fascinating stuff!! I hope you will post more about your research into the Sumerian beer and ancient brewing techniques.
I too have heard the theory about grains being cultivated for beer rather than bread, but it always seemed to me that "all grain" brewing was a tough way to generate sugar for fermentation by ancient civilizations struggling to survive. Mead usually lays claim to being the oldest fermented beverage due the ready made fermentables in honey, but the Sumerian beer would seem to predate most Mead origin stories.
This was another interesting re-creation of ancient 'extreme' brewing techinque and a graphic illustration of the importance of the 'hot side' for sanitization as well as extraction and another example of early enzymologists!