The human eye detects differences in beer color that are missed by equipment currently used in breweries, according to brewing expert Charles Bamforth of the University of California, Davis. Brewers need better methods to check beer color, especially for ales and stouts, he said. Color is an important selling point for beer. Brewers need to check the consistency of batches of beer, and with the trend to microbrews, more amber beers, stouts and ales have come onto the U.S. market. Deeper, more complex colors are an important part of the style of these beers. Breweries use a machine called a spectrophotometer to check beer color during production, but this measures only light of a certain wavelength, said Bamforth. Bamforth's laboratory compared the standard method recommended by the American Society of Brewing Chemists with a human test. A British ale, a U.S. lager, a European lager and a stout were diluted so that they all gave the same reading on the machine. The human judges easily spotted color differences that the machine did not pick up. The study shows that consumers see beer color in ways that a one-wavelength machine does not pick up, said Bamforth. Humans cannot replace machines on the bottling lines, but brewers need to find better ways to check on beer color and hue, especially for production of darker beers. The research was published in the Journal of the American Society of Brewing Chemists.