Humboldtians in Focus

The Lord of the Beans

By Georg Scholl

These days, coffee isn’t just coffee anymore. How best to enjoy and market the pleasure-seeking society’s drug of choice has long since become a science. Kosmos meets an insider.

Sample roasting: what do the beans look like?
Sample roasting: what do the
beans look like? Are there colour
differences or damaged beans?
Both would affect the flavour.

Photo: Frank Schwarzbach

Flowery, woody, bitter, cereal ... butter toffee. Chahan Yeretzian knows many words to describe the flavour of coffee. Twelve of them, to be precise. Yeretzian is a coffee scientist. You could also call him a coffee expert, but you might not be doing the researcher, who was born in Syria, emigrated to Switzerland with his family when he was seven and grew up to become a chemist, any favours. Coffee experts are ten a penny nowadays, and it seems their numbers are growing by the hour: those whose homes are adorned with enormous, elaborate coffee machines that can barely be operated without intimate knowledge of doorstep-sized manuals, who turn up their noses at normal supermarket coffee and will only acquire their specially roasted beans from Internet mail-order companies. Those who have finally found a way to indulge their childhood passion for steam engines by spending time meticulously twiddling little knobs and dials to calibrate steam pressure and grinding levels before making a cup of coffee, and twice as much time afterwards cleaning and maintaining their high-chrome, high-power espresso machines. And especially those in the marketing departments who turned the barista, a barkeeper for coffee, into an advertising character and who rub their hands with glee because customers are happy to spend more on minutely portioned, dazzlingly titled coffees (“Monsooned Malabar Selection”!) than they ever did on the good old pound of instant that was the coffee roasters’ trusty standard for decades, and is now possibly threatened with extinction.

You might be forgiven for finding all this – the advertising, the experts and all the fuss about coffee – mildly amusing. But anyone who talks to Chahan Yeretzian about the role of beans, ideal grinding and optimum pressure will know it’s all true. It’s also scientifically provable. And it’s extremely interesting to the industry: Yeretzian worked for Swiss food giant Nestlé for twelve years and was involved in developing the Nespresso system which, with George Clooney advertising the capsules, has taken the world by storm. For the last four years, he has been working at the centre of excellence for the Science and Art of Coffee at Zurich University of Applied Sciences (ZHAW).

How much did George Clooney know?

Now, which was the mauve one? Hollywood star, George Clooney, advertises Nestlé.
Now, which was the mauve one?
Hollywood star, George Clooney,
advertises Nestlé. The Swiss
company has managed to turn
coffee in colourful aluminium
capsules into a lifestyle brand.

Photo: Nespresso

So what about Nespresso? Is there really a vast amount of research behind it? Did George Clooney ever drop by the lab? If he finds the question about George Clooney a little silly, Yeretzian doesn’t show it. His responses are friendly, factual and delivered in a placid Swiss accent. “Yes, George Clooney actually did get us to explain how it works. He knows what’s behind it all.” But would the actor and most prominent face of Nespresso be able to distinguish between the flavours of the 16 different coffee varieties, called “Grand Cru” in a far from incidental nod to high-class wines? Would anyone? That was precisely the problem Yeretzian was tasked with solving.

In another similarity to wine, there are also professional tasters for coffee, who, with a look of intense concentration and an audible slurp, take a few drops of coffee into their mouths by means of a small spoon – it always has to be the same one, otherwise it may adulterate the impression –, swill them around and spit them back out. Their aromatic impressions are then noted on a form. But even with the best testers this method cannot produce a standardised, unadulterated result that is always the same. Different people experience different flavours too differently; individual sense of taste is too unreliable. But Nestlé wanted reproducible results, says Yeretzian as he explains his job there. The capsule labelled “Livanto” should always contain coffee with a flavour that is equally reminiscent of roasted and caramel notes. “Vivalto Lungo” should always taste flowery and roasted, while the “Rosabaya” variety should always remind its drinkers of the taste of wine, with a subtle acidity and typical notes of red berries – regardless of the coffee batch from which the respective capsule comes. Ensuring this unvarying outcome during the production process by selecting the right beans, roasting and grinding parameters is clearly a challenge. But making it possible at all requires the ability to test the aroma during the production process. The method Yeretzian helped to develop uses a mass spectrometer that analyses the consistency of the coffee flavouring compounds and translates it into three-dimensional graphics similar to topographical maps. This coffee topography is transferred to a matrix with the twelve flavour types from flowery to woody, giving each variety its individual flavour profile – standardised, testable and reproducible

“Every coffee drinker is different. What a coffee really tastes like depends on the form of the oral cavity and where the coffee first touches the tongue.”

Whether consumers would even notice if their “Rosabaya” capsules accidentally contained “Livanto” is of course a matter of speculation. But it presumably increases their enjoyment if they savour their espresso safe in the knowledge that they have not fallen prey to a mere marketing ploy that talks them into buying colourful capsules with fantasy names at exorbitant prices that, in the end, all contain more or less the same stuff. This is probably also one of the reasons why Nestlé actively advertises with the scientists involved in the project, some of whom even feature on posters in the exclusive Nespresso shops to vouch for how innovative and reputable the system is and how very much it’s all worth its comparatively high price. In a consumer world where enjoying coffee has become a science, this approach is only logical.

But for Yeretzian, analysing coffee and making the results reproducible is only the first step on the path to perfect pleasure. He wants to know what flavour actually reaches the drinker. And this is where the standard models abruptly reach their limits. Every coffee drinker is different. What a coffee really tastes like depends, for example, on the form of the oral cavity, on how one drinks and where the coffee first touches the tongue, how the flavours unfold in one’s mouth and nose. In order to form an impression of this highly individual experience, the chemist analyses the aromas streaming from coffee drinkers’ noses as they breathe out after taking a sip of coffee. “Of the approximately one thousand flavours that can be found in coffee, only about 25 compounds are really relevant to its taste,” says Yeretzian. But the temperature, consistency and appearance of the drink, and, not least, personal experience or prejudice, in favour of fair trade coffee or national brands, for example, also affect how coffee tastes to the individual.

Healthier than we thought: coffee contains antioxidants that may be effective against cancer.
Healthier than we thought: coffee
contains antioxidants that
may be effective against cancer.

Photo: Frank Schwarzbach

That these findings are extremely valuable for the coffee industry and its marketing departments is no coincidence, but rather the declared aim of the centre of excellence for coffee at ZHAW, which is designed to strengthen Switzerland as a producer of coffee and coffee machines. In all, the Swiss coffee industry generates approximately 4.7 billion francs, says Yeretzian, who not only conducts research with his colleagues but also trains future coffee experts. The university has recently introduced a postgraduate degree course on The Science and Art of Coffee.

In addition to its flavour, the effect of coffee on health is a further field of research that interests consumers and the industry alike. Here, too, there are differences between individuals. “Coffee isn’t particularly healthy, but neither is it particularly unhealthy, as it was long thought to be. If your hands start shaking after a single cup, you should of course avoid coffee and caffeine. But everyone else has no negative health effects to fear, on the contrary,” says Yeretzian, adding that if you drink between one and six cups a day for many years, you may even hope for health benefits. Coffee contains polyphenols, antioxidants that may, for example, protect against cancer. Some are generated when the beans are roasted; others are already contained in the green bean. How many, depends on the heat and duration of the roasting process. The ideal procedure that Yeretzian is now searching for would produce coffee that combines a high proportion of polyphenols with an excellent taste.

From a Turkish concoction to a functional food

Coffee research, it seems, is pure application and a lot of lab work. Or is it? Chahan Yeretzian, who spends more or less the entire working day in a lab coat, disagrees. Sure, as a natural scientist coffee fascinates him because its chemistry is so complex. “But coffee research is also an ideal field for interdisciplinary collaboration, for example with medical scientists or engineers, but also with historians, philosophers or sociologists.” Just think of the social acceptance of coffee, which was initially regarded with suspicion as a Turkish concoction harmful to body and soul and in the 18th century, was considered by some as a drug that should be prohibited. Today, coffee is an integral part of our achievement-oriented and pleasure- seeking society, he opines, and perhaps the only drink that we imbibe both to relax and to stimulate – a true functional food and contemporary lifestyle product. But the researcher is also driven by another, more personal motivation: “I love coffee.” Yeretzian drinks about eight cups a day. Which leaves one extremely important question for the experts at home: which system does the scientist use to brew his own coffee? For a brief moment, one hopes he might reply that his is filtered coffee made with Grandma’s good old plastic filter cone. Of course not. “At home, espresso from capsules; in the lab, a portafilter machine.” Owners of these devices can now relax; everyone else should perhaps consider revising their list of intended purchases.


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Chahan Yeretzian
Chahan Yeretzian
Photo: Frank Schwarzbach

Professor Dr. Chahan Yeretz ian teaches and conducts research at the centre of excellence for the Science and Art of Coffee at Zurich University of Applied Sciences in Switzerland. As a Humboldtian he worked at Technische Universität München in the 1990s.

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