Crimson Cup and Otterbein University Brew Up Engineering Competition to Automate Coffee Drying

December 21, 2023 (Published: March 2, 2018)
Coffee Buyer Dave Eldridge with Otterbein engineering students

Otterbein engineering students with coffee buyer Dave Eldridge from Crimson Cup Coffee & TeaCrimson Cup recently partnered with Otterbein University’s Harpster Engineering Lab in a competition to design a mechanical coffee parchment raking system. Twelve teams of students competed in the contest. Members of the winning team included Lorraine Burger, Mitchell McClain and Adam Stotler (pictured above with Dave Eldridge, right).

“Working with Dr. Michael Hudoba, we asked student teams to develop an automated coffee drying system that could increase efficiencies on the farm by reducing labor,” said Coffee Buyer Dave Eldridge. “Improving control over the drying process is one way to improve the consistency of coffee quality and reduce waste.”

Dr. Hudoba said, “Engineering, at its core, is about solving problems. The project we developed with Crimson Cup was a great way for Otterbein Engineering students to put their skills into practice and solve a real-world problem from an industry partner.”

Otterbein university coffee drying machine prototypeDave noted that coffee is an incredibly labor-intensive crop. Coffee trees produce cherries, which workers pick by hand.  A de-pulping process separates the outer fruit from the seeds that are the actual coffee beans. After de-pulping, however, a heavy layer of mucilage still surrounds the beans.

The wet process of preparing coffee requires steeping the de-pulped coffee beans in large cisterns filled with water to allow the mucilage to ferment off the bean. Once fermentation is complete, a layer of parchment still surrounds the coffee beans, which must be dried before this parchment can be removed.

In patio drying, workers spread coffee beans in parchment on concrete patios to dry in the sun. Using a raised drying bed offers more control and consistency. However, both methods require workers to rake or turn the beans by hand to ensure even drying and prevent mildew.

coffee drying machine prototype“We challenged students to come up with a machine that would reduce labor requirements while improving the efficiency of parchment drying process,” Dave said. “They were judged on drying efficiency and consistency as well as power consumption, since electrical power is often not available on remote coffee farms.” Students used 9-volt batteries as a power source so that the equipment could run on simple solar panels in the field.

Dr. Hudoba said that Otterbein focuses not only on form and function, but also on teamwork and technical communication. “The great thing about these projects is the freedom we give to the students to create and innovate,” he said. “We give them a problem statement, a budget and design parameters. The rest is up to them. This freedom to be creative is what allowed our students to come up with really unique solutions to a challenging problem.”

As the client, Dave consulted with student teams throughout the semester. “It was a pleasure to work with Dr. Hudoba and his students on this project,” he said. “I was impressed by the creativity the teams displayed in coming up with unique approaches.”

Crimson Cup works with numerous small-plot coffee farmers through our Friend2Farmer direct trade program. An ongoing goal is to help farmers improve coffee quality and consistency so they are able to receive a better price for their product.

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