STiR coffee and tea magazine

58 STiR coffee and tea / Issue 5, 2018 (October / November) By Daniel Ephraim ne might assume that the process of placing a pod into a single-serve maker, and brewing that delicious, on-demand espresso, is simple and straightforward; however, by taking a deeper dive into the development of that pod, it is remarkable to understand the high degree of art and science packed into one small product. Let us take a journey into some of this understanding. The advancement of the quality single-serve coffee market would be impossible without the development of engineered grinding (particle reduction) equipment to accompany the growth of this market. Some of the revolutionary developments include: 1) The grinding technology required to produce sophisticated grind profiles, and 2) The invention and development of a coffee normalizing system that "compacts" the coffee without loss of integrity. Additionally, both technologies need to operate in a water-cooled (chilled) and precisely controlled environment to ensure that the coffee exiting the grinding system is as cool, and full of aromatics and volatiles, as the beans that entered the grinding system. The result: The grinding equipment considerations described above allow for a single-serve product with an almost 600% increase in value (as compared to, say, a fresh brew product). For example, a coarse filter brew grind of, roughly, 800 microns (μm) will have a retail value of $0.02 - $0.03 per gram, while a sophisticated grind in a capsule will sell for approximately 100% more ($0.04 - $0.05 per gram). Simi- larly, an espresso-style grind will sell for 600% more than the filter brew ground value, or $0.12 per gram (see below). Precise Perfection Precision grinding is essential to proper coffee capsule extraction O Magnified view of coffee bean The technologies developed around the single-serve market are the result of challenges inherent in producing an optimal product on a consistent basis. A more in-depth understand- ing of those requirements allows us to understand the "why" behind the development of these sophisticated technologies, which were explicitly established to correct what would other- wise be barriers to a successful product. Why is grind important? The most critical concept in coffee grinding technology in gen- eral and with single-serve, in particular, is the managed extrac- tion of the soluble solids from the colloidal structure of the cof- fee cells within the coffee bean, as shown below. This concept is the "secret sauce" of coffee brewing. If the extraction rate is low, coffee strength is compromised; conversely, if the extrac- tion rate is excessive, there is an extraction of some of the lesser desirable components, which is deleterious to the achievement of the optimal brewed coffee result. The image below is a much-magnified view of ground cof- fee particles using an electron microscope. The cellular walls are about 30 microns in diameter, and the colloidal material fills the voids within the ground coffee and cellular structures. Part of this colloidal material is what we want to extract, but with a limit. The physics behind grinding coffee and soluble solids extraction: The extraction of soluble solids from the ground coffee par- ticles is a function of the exposed surface area of the ground coffee to the extraction media, in this case, water (hot or cold). As the area exposed to water increases through grinding, the greater the extraction due to the area exposed to the water. The table below demonstrates this relationship. Copyright 2018 Modem Process Equiment Corporation

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