The water-to-beer ratio. From the Texas Living Waters Project:
"Water is a key ingredient in the production of beer, of course. But it might surprise you to know that as of 2008, it took 4.1 barrels of water to produce one barrel of beer brewed by MillerCoors. This is referred to as the water-to-beer ratio. In 2008, MillerCoors set a goal of reducing that water-to-beer ratio by 2015 so that it only would take 3.5 barrels of water to produce one barrel of beer. That wasn’t an idle target; the brewer has already met that mark. They did it through a variety of measures, including not only water use reductions at their eight breweries in the United States (including one in the Fort Worth area) but also by altering water irrigation practices on the farms of their barley growers in Idaho and elsewhere. For example, through a partnership with The Nature Conservancy (TNC) and barley growers in the Silver Creek area of Idaho, on one farm alone, MillerCoors and TNC helped to reduce water use by 20% from historic levels (419,000 gallons of water saved each year on this one farm)."