Beer, and the biochemists behind it

It was none other than Benjamin Franklin who said: "Beer is living proof that God loves us and wants us to be happy." But for such a revered drink, the steps to making beer are actually quite basic -- simply bottle (or can) the alcoholic fermentation that occurs when yeast is introduced to extracts of malted grain. Still, scientists throughout the ages have spent countless hours tweaking this general formula, communicating their achievements via media ranging from ancient funerary art to this week's lecture on the science of beer at the New York Academy of Sciences.Beer has been around for at least 8,000 years, making brewing quite possibly the world's oldest biotechnology. Archaeologists have scraped beer deposits from ancient Egyptian brewing jars, historians recount how everyone from Pharaoh to farmer drank, and beer was a common offering to the Egyptian Gods. Ancient brewers formed their brew from watered-down fermenting bread dough, styling their beers with extracts from a range of plants, including mandrake (which tastes something like a leek). The "hop," a vine that produces a resin and oil-rich cone that gives beer its characteristic bitter note, didn't enter the recipe until much later, and the cultivation of hops can be traced back to eighth century Germany. Since then, beer as we know it has been a ubiquitous drink in Europe -- indeed, in seventeenth century England, most children drank beer, not water. And scientists have spent years puzzling out how brewing works. In 1680 a draper from Holland, Antonie van Leeuwenhoek, told London's Royal Society that he had developed a microscope that let him zoom in on a drop of fermenting beer, revealing yeast cells. A couple of centuries later, in 1860, a group of brewers asked a tanner's son from Dole -- one Louis Pasteur -- to explain why their beer went sour after fermentation. Pasteur concluded that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells."Today, Charles Bamforth, author of Beer: Tap into the Art and Science of Brewing, is one of the people at the forefront of beer science. This week, Bamforth, chair of the Food Science and Technology Department at the University of California, Davis, participated in the NYAS lecture series on the science of food. UC Davis installed a pilot brewery back in 1959, and trains students to work in technical positions at the nation's breweries. The classes "are very popular," Bamforth admits with a grin. But it's not all play -- the undergraduate degree requires instruction in microbial process, plant physiology, and the biochemistry and chemistry of brewing. Some 125 billion liters of beer are brewed worldwide every year, and most is made from barley. (Some German beers are made from wheat, and you can pick up a goat's milk beer in Tibet.) Today's brewers like barley because its husk acts as a filter that separates the liquid extract of sugars, an essential part of beer-making. However, raw barley is astringent and leaves a grainy aftertaste -- as a remedy, brewers germinate the grain, a process called malting. The embryo produces hormones that switch on enzymes (amylases) that chomp through the cell walls and some of the protein in the starchy endosperm, turning the grain from jaw-crackingly hard to chewable. Experienced "maltsters" can gauge when the barley is sufficiently germinated by using an ancient scientific technique: crushing a few grains between their fingers. Bamforth emphasizes that the basic principles of beer-making have not changed much over time. "If it ain't broke," he shrugs, "don't fix it." What has changed enormously is our scientific understanding of this age-old process, which has allowed brewers to customize their brews. To make darker brews, leave the malt longer in the kiln; to lighten the flavor and calories, add more water (beer's largest ingredient). Scientists have pinpointed the different beer-making strains of yeast and hops, but brewers typically keep their strains a secret since they play a significant role in distinguishing one brand from another. Still, Bamforth says that there are many ways to improve beer and its journey from grain to glass. For instance, scientists understand little about oxidation, which takes place throughout the brewing process, but is critical to beer's shelf-life -- if oxidized polyphenols crosslink with proteins, they cloud the beer, leaving it unpalatable. And one day, maltsters and brewers may turn to biochemists, using gene technology to create genetically modified materials, Bamforth predicts. But brewers are also a cautious breed, and although one genetically modified brewing yeast has been cleared for use in the UK, as of yet no brewery has used it. "It's in a freezer," Bamforth says, "waiting." Kate Thomas mail@the-scientist.comLinks within this articleA. McCook, "Beer review," The Scientist blog, January 20, 2006. http://www.the-scientist.com/blog/display/22991Science of beer http://www.nyas.org/events/eventDetail.asp?eventID=7902&date=2/26/2007%206:00:00%20PMK. Thomas, "From chemist to chef," The Scientist, November 3, 2006 'http://www.the-scientist.com/news/display/27998R. Kaufman, "Renowned microorganism researcher receives 117-year old Dutch award," The Scientist, June 22, 1992. http://www.the-scientist.com/article/display/11414/A. Dorozynski, "Pasteur at 100: Echoes of past, future promise," The Scientist, October 5, 1987 'http://www.the-scientist.com/article/display/7890Charles Bamforth http://foodscience.ucdavis.edu/bamforthC. Bamforth, Beer: Tap into the art and science of brewing http://www.amazon.com/Beer-Tap-Into-Science-Brewing/dp/0195154797NYAS science of food series http://www.nyas.org/ebriefreps/splash.asp?intEbriefID=593

Beer, and the biochemists behind it

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