In the process of working with Sierra Nevada on their new brewery in Appalachia, I've been digging deeply into determining the amount of energy and water required to make a beer.
There is inevitable water use (you drink it) and energy use (the grain is milled, mashed, cooked, etc), but there are opportunities to minimize both.
Turns out brewers, and the beer industry generally, are big proponents of both energy and water efficiency. They are surprisingly forthcoming about their brewing process and energy consumption. I've worked with more manufacturing sectors than I can count, and breweries stand out.
So how much energy does it take to make a beer? According to a 2012 worldwide surveying effort, average energy consumption is 207 mega-Joules per hundred liters of beer produced. That's about 0.2 kilowatt-hours per bottle, or enough energy to run your 40 inch Energy Star TV for 3 hours and 20 minutes. Your six pack probably was made with enough energy to run that TV for 20 hours. Yikes. Of course, different size breweries use different amounts of energy, and some types of beers are more energy intensive than others.
The good news is that the industry has consistently been reducing that number. The same survey of breweries has been done every four years since 2000, and the average energy consumption per beer has dropped every time, and by about 30% since the first survey. I can tell you from working with Sierra Nevada that the number could go down even more.