25 seconds to the perfect espresso

The secret to the perfect espresso lies tucked away in the Dutch town of Enschede, a little under ten kilometres from the German border. More precisely, it is in the facilities of the PCV Group’s product developers, who, over the past 25 years, have applied their expertise to support almost every well-known coffee machine manufacturer. Their particular specialism lies in dosing processes. The clients of this ‘high-tech foundry’ also include leading companies from the consumer goods industry and other sectors. Many of the PCV Group’s consultants, engineers and industrial designers are passionate coffee experts and understand every facet of the topic. These coffee pros have taken on board the fact that preparing the most perfect coffee possible not only requires raw materials of outstanding quality and the experience and touch of an experienced barista, but also involves a wide range of other factors. Brewing coffee is a complex procedure that can be optimised with the help of sophisticated technological solutions.

Man versus machine

After participating in a barista training course, Hedzer van der Kamp, one of PCV’s experts, realised that man and machine share the same goal: “Professional baristas and coffee machine manufacturers alike strive to guarantee a consistently high level of quality, by taking into account as many variables as possible. In this regard, technology is superior to humans, and also becoming more and more accessible and affordable. Therefore, the process will become increasingly automated in the future.” It is very clear that coffee is a topic close to people’s hearts. The Internet is full of articles and opinions on this stimulating drink, yet only one thing is certain: tastes differ widely. We can better understand this by looking more closely at the variables alluded to above.

Quantity, grinding result and more

Everything depends on the quality of the beans. This is essentially determined by the cultivation method, transport and storage conditions, as well as roasting, while the amount of coffee used and consistency of the powder play an important role. Thus, both baristas and machines benefit most from a coffee grinder of outstanding quality. According to Van der Kamp, it is hard enough on its own to achieve a consistent output of a continuously homogenous dose, which is why many producers continue to choose a less than optimal standard in the development of automatic machines. The PCV Group, however, does not settle for this option. “As engineers and product developers, we must look at even the smallest details by determining the correct dosage, constant water temperature, appropriate amount of water and correct pressure more and more precisely and continue to refine the combination of different influencing factors.” A simple example that all at PCV agree upon is that “It definitely takes 25 seconds to brew the perfect espresso. The pressure applied should force the water through the ground coffee within this length of time, if you want to achieve the proper infusion.”

Tasting required

“Brewing coffee is basically little more than dissolving coffee substances in water. More precisely, this concerns extracting around 20 percent of all the soluble constituents of each coffee particle. We call that the total dissolved solids (TDS), and it is a standard that every expert knows.” Far more interesting, however, according to Van der Kamp, is the extraction consistency. A cup with too little extracted coffee is often weak and tastes sour, whereas a too intensive extraction leads to a clashing, bitter and strong coffee flavour. If a coffee exhibits a combination of both extraction levels, it takes on a stale taste – even if the TDS value is spot-on. “One can only recognise the lack of design in a machine through measurement and sensory evaluation. In other words, by tasting it.” states Van der Kamp.

National differences

The fine balance between strength, extraction and brewing formula required to create a good tasting coffee is internationally recorded in the extraction diagram (Brewing Control Chart) for preparing coffee. Various American and European varieties have been established by means of this diagram. The taste of espresso varies widely between (Central-) Europe and the espresso’s homeland, Italy. “Even when we have everything under control, in practice, the overall minor deviations form a pattern that can be ruined by cleaning or a change in the dose, for example.” The art is to remain within the boundaries of the extraction diagram while, at the same time, taking full advantage of the wide range of factors that are important for a good cup of coffee. “This is done by tinkering with various adjustment screws and combinations. And it’s this fine-tuning that makes this craft so much fun for us.”

Second opinion

The PCV Group experts are regularly asked to provide second opinions on coffee machines that aren’t working optimally, or to consult on design and quality aspects. They use a systematic method that, combined with strong experience and theoretical knowledge, contribute to further development. “We have available a growing number of design variables that affect the final result. Regardless of whether we’re talking about compact, semi- or fully-automatic machines, consumer and ‘professional’ coffee becoming ever more a matter of personal taste. So it is important for us to achieve an optimal performance within the given parameters. The smooth interplay between man and technology is what we are after.” Says Van der Kamp, explaining the challenge.

What will the future bring?

At the PCV Group, one is convinced that coffee machines are becoming more and more intelligent and the demands of their users are increasing. As a result, experts predict that more and more smart technologies which have yet to be implemented, or are not yet available for reasons of cost, will be used in the consumer goods sector in coming years. This particularly concerns sensors that monitor the dose, amount of coffee and grinding consistency. Coffee machines are largely still designed around fast pre-heating systems, while the focus will shift towards feedback systems. “Through the Internet of Things and more tailored mixtures, the coffee sector will become more and more diverse over the next ten years”, van der Kamp predicts. And what about the professional market? “Professional application will continue to be the main driving force behind development. One can expect fully-automatic machines to replace semi-automatic ones, which stems from the fact that today, every business wants to be able to serve a perfect cup of coffee, but cannot always train someone as a fully fledged barista”. At least one thing will certainly stay the same: “It will always take 25 seconds to brew the perfect espresso.”

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