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The science of taste

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Professional tasters deconstruct beer down to the details.

By Kate Prengaman

Roy Desrochers drinks beer for a living. And, he jokes, his belly proves that he takes his profession seriously. But despite his gregarious nature, the work of a professional beer taster turns out to be more serious and complicated than just enjoying a cold pint.

“You can go to college and get a Ph.D. in less time than it takes to become a certified beer taster.  This is serious stuff,” Desrochers said.
Desrochers works as a sensory analysis consultant, teaching people to taste beer since the 1980s. Every year, he teaches a class in the science of taste for the Master Brewers Association of America. “I really encourage people to learn the sensory,” said Karl Ockert, the technical director for the MBAA. “I really think that brewers need to taste their products more.”

In his course, Desrochers explains to brewers that while they design innovative brews, they need to keep in mind the importance of harmonious flavors. Budweiser is the most popular beer in the country, not because it has no taste, as some contend, but because the flavors blend together seamlessly, according to professional taster ratings.

Consumers prefer harmonious flavors, but can’t usually describe why. They don’t have the sensory vocabulary to explain their preferences. So brewers turn to professional tasters, who can translate tastes into specific variables that can be used to adjust flavors and improve beers.  “The industry I work in is all about becoming an instrument,” Desrochers said. “You have to get rid of your personal preferences.”

Once trained, professional tasters can precisely measure flavors. Desrochers explained that the process of sensory analysis uses people as instruments to measure sensory response to stimuli, not to offer opinions on whether or not they like a beer. For beer, they fill out a flavor profile with categories for aroma, flavor and aftertaste. Each specific quality, from a burnt caramel malt aroma to a piney aftertaste, is measured on a seven-point scale.

Beyond breaking down the flavor profile, tasters identify specific chemical flavor compounds. Jon Roll, a University of Wisconsin faculty associate who teaches brewing classes for undergrads in microbiology, points out that more than 10,000 compounds can form during the fermentation process.  Some make beer delicious, and others, disappointing.

To practice, Desrochers’ brewer students taste small servings of beer, each spiked with a different off-flavor that can occur during the brewing process. The goal is to learn to associate the unpleasant flavor with a particular compound. With the problem identified, they can go back in the brewing process and fix whatever has gone wrong. One sample tastes like movie popcorn fake butter: It’s a byproduct of fermentation that brewers try to avoid. Another sample smells like sweaty socks, resulting from a microbial infection.

Another challenge for professional tasters is the fact that heavy drinkers consume 80 percent of the beer sold in America and their seventh beer does not necessarily taste like the first one. Scientists call the phenomenon sensory fatigue. After continuous exposure to a certain stimuli, like the taste of sugar, your perception of the sugar’s sweetness fades away.  To test for sensory fatigue in beer, tasters will drink 16 identical beers in two hours.

“It’s amazing, because you can have two beers that taste identical on the first sip, but by the sixth, seventh, eighth beer, they taste completely different.” Desrochers said. “Some beers, you drink a whole bunch and you continue to get better flavors. Some beers, you drink a couple and you can’t taste anything anymore; you blank out. Some beers, the more you drink, the more bitter it seems.”

It turns out bitterness is the most critical element in beer tasting. According to Desrochers, it’s the most difficult taste to calculate, even for pros. Our taste buds cannot recognize anything until it dissolves in saliva, but bitter compounds resist dissolving. The tongue can only sense five things: sweet, salty, sour, bitter and umami. Sweet and sour tastes contribute to beer, but bitter is the key.

Beyond the aforementioned five, the rest of our sense of taste comes from our nose. When you take a sip, compounds from the beer travel with your breath from the mouth up the back passage of your nose and stimulate the olfactory area. In this way, the nose does most of the sensing that we call taste.

Desrochers said that his sensory training has made his life more enjoyable, because he knows how to truly appreciate good food and good beer. After 30 years, he still feels lucky to drink beer professionally. “I will never tell anyone what my favorite beer is. People ask me all the time, what’s the best beer? The best is what you like.”

 

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