WMF Group on precision grinders

Besides the quality of beans, grind and brew influence the taste profile of a coffee. During the brewing process, the components within the coffee powder are extracted with the help of water and influenced by temperature, pressure and time. Then there’s grinding. According to Frank Göltenboth, Vice President of Research and Development, Global Business Unit of Coffee Machines at WMF Group, the grinding degree is determined by what is known as the gap dimension. Changes in the grinding gap by just a hair’s breadth of just 0.05 millimetres can lead to a noticeably different coffee taste. “[It] not only influences which substances are released from the coffee powder, but also the extraction time – both decisive factors for the coffee taste,” Göltenboth says. “The size of the coffee grains, and thus their surface area, are influenced by the grind setting on the grinder.” Many small grains (fine grinding) have a much larger surface area than coarser grains (coarser grinding), which provides better access to ingredients in the brewing process. WMF service technicians say an extraction time of 20 to 25 seconds is standard for a typical double shot of espresso. WMF says somewhat coarser grinds do not have a notable influence on extraction time – personal taste preference is the deciding factor here. Grind quantities are then defined and set for every other coffee beverage within WMF’s range of fully automated machines. However, Göltenboth says receipes are easily customised to suit individual taste preferences, simply by applying different grind degrees. Such knowledge is the work of WMF’s highly skilled engineers who have helped build WMF Group’s reputation for producing quality coffee machines and professional grinders for the past 160 years. Despite decades of design and production experience and using state-of-the-art manufacturing techniques, Göltenboth says in a crowded and competitive marketplace, retaining high quality production and consistency is key to being a dominant player in the global market, and it all begins at the installation phase. “Professional grinders from WMF have very precise, high-resolution grinding degree settings, which can be adjusted both manually and, with the high-end devices of the newest generation, electronically using the touch display of the coffee machine,” Göltenboth says. Tried-and-tested components are constantly being further developed using the latest technologies. Göltenboth adds that the biggest technical change in the production of grinders in the past year is the “immense increase” in the number of components found in each grinder to accommodate consumer demand for customisation and control. “Production facilities had to adapt to this challenge, including those of suppliers. Individual parts of the grinders, such as the grinder housing, benefit from our suppliers’ modern machinery. The parts can be produced faster, more precisely and in larger quantities,” Göltenboth says. To retain production consistency, WMF’s certified quality control staff supervise each stage of production and carry out ongoing checks. At WMF Group, every grinder is assembled by hand at the Geislingen an der Steige factory in Germany using the latest ergonomic and technical standards and equipment, including high quality die-cast aluminum parts to ensure constant grind size and quantities. “A professional grinder is characterised by high-quality materials, precise manufacturing and durability of the components. That is the only way to ensure reliable grinding reproduction over tens of thousands of coffee brews,” Göltenboth says. All WMF grinders are equipped with disks right from the start. The advantage, Göltenboth says, is a more precise grinding gap compared to conical grind mechanisms. In this format, beans are ground between two grinder disks and the powdered coffee is transported through an adjustable gap. The other advantage is the ability to adjust the grinding degree and grind quality according to the needs of different beans and individual preference. “Service technicians draw on their coffee expertise, because some roasts require finer, some coarser grindings in order to achieve the desired coffee taste,” Göltenboth says. Once the grinder construction is complete, it undergoes testing on an automatic test stand to ensure the machine delivers the same precise settings and grind degrees as intended. The grinder then undertakes three test fields to quality the grinder for market use. First, statistical test methods are used to influence the grind degree and quantities with a number of influencing factors to test its grinding functionality, such as grind gap and ambient conditions. In the second test, the grinder is subjected to continuous operation. The third, and probably the most comprehensive test, is field data evaluation. Different operating situations and bean types have an effect on the grinder and as such, all variables are tested to ensure the machine grinder can function on a broad basis. The ultimate test, however, is that of baristas, cafés and restaurant operators that utilise WMF’s products. “The technology has to be constantly aligned with the experiences and sensations that result in good coffee. What better way to do that than with a barista or roaster?” Göltenboth says. As such, WMF hosts joint workshops and training programs to exchange experience and knowledge with its target audience. One such technological request was further control. To cater for this, WMF fully automatic machines from its New Generation platform are able to monitor the grinding degree and regulate it to the optimal level if needed. To target specific beverage profiles, WMF offers machines with up to four grinders, such as its new flagship WMF 9000 S+. The individual grinders are assigned to the individual coffee beverages, meaning the grinding degree for specialty bean types can be adjusted. A separate grinder for every type of bean also prevents the mixing of residues of different bean types in the grinder. WMF’s 1500 S+ grinder features WMF’s Dynamic Coffee Assist functionality, which Göltenboth says guarantees the highest quality of espresso-based coffee specialties. Once the beverage has been selected, the Dynamic Coffee Assist function monitors the extraction time continuously, and automatically makes adjustments where necessary. Since 1853, consumers have put their trust in WMF products. The brand embraces a “Made in Germany” tagline which Göltenboth says is a seal of approval that it not only represents the best products which comply with the strictest International Organization for Standardization (ISO) regulations, but also the high confidence of end consumers worldwide. In a market flooded with choice, Göltenboth says WMF fully automatic machines leave their mark thanks to precision and knowledge of the grinding process in combination with software algorithms that monitor and support consistency, and “bring coffee to life”. After all, Göltenboth says, coffee excellence should always be one thing: a premium experience.

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