Issue link: https://read.dmtmag.com/i/491350
32 STiR tea & coffee industry international Manufacturers once trumpeted the latest optics. Light sources, lenses, visual sensors are still part of the story but today's coffee growers want energy efficiency at high volumes, billion-cycle ejector valves, bichromatic and trichromatic sort flexibility and multiple channels along with training and support. OSTA RICA — "Have you heard about 'The Oliver?'" asked Price Peterson, owner of the famous Hacienda La Esmeralda coffee plantation in Panama. Peterson described how this now classic machine shakes green coffee as it moves along a tilted, vibrating deck using gravity to separate beans that are less dense. This long-established method yields better coffee because the higher the elevation the beans are grown the greater their density and quality. Many mills still use similar machines to process coffee before shipping. However, the coffee trade has evolved quite a bit since the days when green beans were sold by density. Machines used to sort the good from the bad have advanced too. Optical sorters were first developed around the time that the Oliver Manufactur- ing Company was incorporated in 1930. ESM (short for Electronic Sorting Machines) manufactured sorters in the 1930s in a process that involves three steps: 1) bulk coffee is fed into the machine by a chute that narrows, forcing the beans into uniform mono- layer or "curtain"; 2) light is reflected off every bean and recorded by two or three cameras that view the coffee from different angles as it leaves the chute; and 3) coffee beans that match the profile free fall while defective beans are deflected midair by a millisecond blast from a nozzle that turns off and on in .25 msec. Advances in electric engineering and the development of a mass market for com- puter electronics along with consumer demand for higher quality coffee spurred inno- Rejecting Defects The Ins and Outs of Optical Sorting Bühler's SORTEX A MultiVision Three channel Xeltron Máquina XR with 32-bit Edge Technology C By Jenny Neill