How Much Water Goes Into a Burger?
Studies Find Different Answers
CARL BIALIK / Wall Street Journal 11jan2008
THE NUMBERS GUY
A fast-food quarter-pounder costs $3, and 1,300 gallons of water. That's how much it takes, per burger, to hydrate the cow, grow its food and process its carcass, according to the Web sites of the National Park Service, the U.S. Geological Survey and a bottled-water trade group. By contrast, a loaf of bread uses up 150 gallons, and milk requires just 65.
The message dovetails with the goals of environmental meal-managing: Eat meat, and you're using up a precious natural resource.
That message is broadly correct, but the number itself is disputed. It stems from decades-old research conducted by California scientists for a presentation to a local high school's future farmers class. One of the scientists now says the number is too high. A more thorough investigation by an independent group halved the figure. And a researcher funded by the cattle industry reduced it still further.
Asked to speak at Colusa High School in the 1970s, Thomas M. Aldrich, a Colusa-based scientist with the University of California Cooperative Extension, decided the budding agriculturalists would enjoy a presentation on the water usage of various foods. To help him, he tapped his colleague, Herbert Schulbach. The two compiled data from California studies and farmers' reports on how much water was needed for various agricultural products and for animal feed.
The result, Mr. Aldrich recalls, was that a burger and fries "took almost a swimming pool to produce. It was kind of awesome that you need that much water for that much food."
The cattle industry didn't find the result so awesome. "We came out, made our presentation, and all hell broke lose," Mr. Aldrich says. Nonetheless, it wasn't until 1993 that the industry-funded study appeared. Mr. Aldrich now says that his study was in the "95th percentile" for accuracy in its time but shouldn't be cited now. "I would say that that figure would not be right," he says. "I think it would be too high."
The Sacramento-based Water Education Foundation had been using the Colusa scientists' numbers on a slide rule it distributed to educate students about water consumption. "It had been produced on the back of an envelope," says Marcia Kreith, now a program analyst at the Agricultural Issues Center at the University of California, Davis. "It was a good, reasonable estimate, but they couldn't document how they got their numbers." The Colusa scientists published their results in a newsletter and didn't explain all of their assumptions. (Three decades later, both are retired and don't recall some details.)
The foundation hired Ms. Kreith to look into the issue. The resulting study, in 1991, tried to systematize the water-consumption problem. She laid out 20 assumptions common to all the dozens of foods studied, looked at local data from throughout the state on water usage and crops, and consulted with agricultural experts to arrive at estimates for such things as the amount of water pregnant cows drink daily (8.7 gallons, when not lactating; 16.9 gallons when they are). Her estimate for a burger's total water use: 616 gallons.
"To all those who so eloquently tried to make the case that the use of numbers can be a mystical process leading to nowhere," Ms. Kreith wrote, "the author responds that the methodology used in this study is as objective as she is able to make it."
One of Ms. Kreith's assumptions was that rainwater counts. The thinking, she says, is that with any fresh water, there's an opportunity cost -- the range land could have been used by other animals. But critics say range land is inappropriate for raising other crops, and the California Beef Council helped to fund a peer-reviewed study that excluded rainwater. That study found that a quarter pound of beef takes just over 100 gallons of water.
Howard Perlman, the hydrologist who set up the Geological Survey's Web page on foods' water use, says that now that he knows there's a range of estimates he will update the page.
None of these numbers, though, includes the water it takes to get the burger from meat-processing plant to plate. "There's canning, freezing, and you have to cook it and wash the pots," Mr. Schulbach says. "An awful lot of water is used in between the field and your mouth."