Many people drink beer without ever knowing what ingredients, and how much of those ingredients, are used to produce it. According to CNN.com, "beer is about 90 percent water, so water is an important ingredient." Other sources cite the percentage of water in beer as being as high as 97 percent. Like other beverages and household items, it takes a significant amount of water to produce even small quantities of beer.
Calculate the percentage of water in one pint of beer by converting the range of 90 percent to 97 percent of beer as water in one pint. Convert 90 percent to 97 percent to a decimal which would yield .90 to .97. Multiply this range by one. So there are .90 to .97 pints of water in one pint of beer.
Convert liters to pints (1 liter = 2.11 pints) because, according to TheEconomist.com, about 300 liters of water go into making one liter of beer. 300 multiplied by 2.11 is 633 pints of water in 2.11 pints of beer. Convert 633 pints to gallons (1 pint = .125 gallons). There are 79.125 gallons of water in 2.11 pints of beer. Divide 79.125 by 2.11 to get 37.5 gallons of water in 1 pint of beer.
View the quote for the amount of gallons of water in a glass of beer from Columbia University in the References Section. According to Columbia University, "Many everyday items require vast amounts of water to produce: glass of beer = 19.8 gallons." It takes 19.8 gallons to make one glass of beer.
Comparing these two figures tells us it takes between 19.8 gallons and 37.5 gallons of water to make a pint of beer. As the Columbia study wasn't clear on how big a glass is and since the Economist is based out of the UK, the sizes of beer glasses can vary.