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Tuesday, February 14, 2012

One man reacts to the Maillard reaction

Good things happen when you bring heat into the mix.

By Steve Siciliano

I think a lot of us would agree that our lives would be less gratifying without hand-crafted beer and freshly roasted coffee. Despite the obvious differences between these delectable beverages they do share something very basic in common—neither would be as delectable if malted grain and green coffee beans did not undergo a complex chemical process known as the Maillard reaction.

The Maillard reaction is named after French chemist Louis-Camille Maillard and occurs when amino acids and reducing sugars are exposed to heat. To say it another way, and with less clarity, when the reactive carbonyl group of the sugar in some food products reacts with the nucleophilic amino group of the amino acids a complex mixture of poorly characterized molecules are formed that are responsible for a wide range of aromas and flavors. Sheesh!

If you have a PhD in food science the previous sentence probably reads like Shakespeare. For those of us who are decidedly non-scientific all we need to know about the Maillard reaction is this—a whole bunch of good things happen when heat is applied to certain food products, including those that are used to produce satisfying pints of home-brewed suds or steaming mugs of home-roasted joe.

Before cereal grains can be used to make beer they must be malted first. After maltsters apply moisture to raw wheat or barley the kernels are allowed to sprout and then germination is halted with gentle heat. Packed full of amino acids and sugars, the kernels of grain are kilned at various temperatures and voilĂ —the Maillard reaction transforms them into the colorful, tasty and aromatic array of raw materials that brewers have at their disposal.

Green coffee beans, like kernels of grain, are packed with amino acids and sugars and folks who roast their own coffee are all the time observing the transformative effects of the Maillard reaction. When the green coffee beans are heated, either in a skillet, a repurposed popcorn popper or a home coffee roasting appliance, they begin to yellow and steam. As the roasting process continues the “first crack” can be heard. It is at this stage that the bound water in the beans is released, the sugars begin to brown and aromas and flavors are produced—the Maillard reaction. After the first crack the roasting process can be halted at any time but for darker roasts the heating is allowed to continue until the “second crack”. The longer the Maillard reaction is allowed to continue the fuller the roast becomes.

Obviously we would still have beer and coffee if some French chemist back in 1912 didn’t take it upon himself to study what happens when heat is applied to certain food products, and knowing that there’s something called the Maillard reaction won’t make us better home brewers or coffee roasters. But you never know when esoteric facts about organic chemistry might come in handy. At the very least it could help pass the time if you ever get trapped in an elevator with a food scientist.

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