STiR coffee and tea magazine

46 STiR coffee and tea / Issue 2, 2019 (April / May) By Dan Bolton G rinding freshly roasted coffee for drip brewers is simple compared to the requirements for capsule production where identically sized particles pose problems. Consistent particle size is a primary con- sideration in drip applications but coffee in capsules must be consistently inconsistent. This is known as bimodal particle distribution, a mix of uniform fines and larger particles that produces a stronger shot of espresso with more body. During the grinding process a single bean is crushed into 500-800 particles to make drip brew. Coffee for capsules is ground to a much finer 3,000- 3,5000 particles, increasing its surface area from 3.5 to 100 cm2. Under a microscope a bimodal grind will display like-sized particles grouped into fines and larger particles. Since different sized particles saturate at different rates, leading to differences in the percentage of extraction, the ideal is to produce uniform groups of slightly irregular shaped particles. This is because coffee that is too finely ground and uniform compacts, slowing waterflow that leads to over-extraction (greater than 20%) and a bitter cup. Uniform particles that are too large lead to channeling, where the water injected into the capsule fails to saturate grounds, leading to weak brew. Neuhaus Neotec developed its three-stage WMS-E series grinders to pre- vent capsule channeling and over-extraction. The speed of each roller is inde- pendent allowing a "fast" and "slow" pairing. Combined with variable grind- ing pressure (roll against roasted bean) this highly dynamic system produces extremely uniform and reproducible particles at high throughput. "Changing the gap and independently changing speed of the rotors is a key factor," says Ralf Torenz, Neuhaus Neotec sales director. Making its roll grind- ers extremely flexible enables bimodal grinds at high speed and large volume. There are many combinations in which facing rotors are sped up slightly on the left and slowed at right, Torenz explains. Corrugated rollers can be paired as sharp to sharp, or sharp-dull, dull-dull, or dull-sharp. Continuous speed regulation and grinding gap adjustment in three stages enables opera- tors to develop a nearly infinite combination of settings that are programmed and easily reproduced, he says. Customized Roll Grinders for Coffee Capsules Michael Ziemann, Neuhaus Neotec Neuhaus Neotec Neogrind three-phase grinder designed for producing a wide range of coffee capsules

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