(121d) Chemical Engineering of Coffee: A Course Prioritizing Experiential Learning (and fun)

Chemical Engineering is at a cross roads. Our traditional applications such as energy and polymers no longer capture the imagination of many young students. Ironically, the core concepts of a chemical engineering education such as heat and mass transfer, separations, thermodynamics, fluid mechanics, reaction engineering and systems engineering are all vastly important underpinnings of the transitions that must occur to support our future economy. Taking advantage of the statistic that Canada is one of the top 10 countries in the world for coffee consumption per capita, with an average of 6.5 kg of coffee consumed per person per year, we have been using coffee as a way to introduce chemical engineering to the general public. Coffee roasting and brewing involves nearly every aspect of the chemical engineering curriculum. An undergraduate club successfully modified our espresso machine to have PID control. The response has been so strong and positive that we have launched a senior elective course on the Chemical Engineering of Coffee that builds on foundational courses that the students have already completed.

The Chemical Engineering of Coffee course uses an experiential learning approach to explore chemical engineering concepts to all aspects of the coffee process, from bean to cup. We have embraced the experiential learning approach for this course emphasizing the four stages of feeling, watching, thinking and especially doing. The course is split between the class room and laboratory, with equal time for lectures and laboratory sessions and equal weightage for laboratory reports and exams in the grading. We explore many chemical engineering aspects of coffee making, including the impact of reactions during the roasting process, mass transfer and flux during brewing, the effect of water chemistry, pressure driven flow though porous media and scale up. Energy use and conservation during the roasting and brewing processes is also be investigated. In at least a minor way, the course helps counteract the perception that chemical engineering designs and operations are difficult to reduce to practice at small scales, since a unit operations perspective can be used to explain each of the aspects mentioned above, and also related to larger scale industrial operations.

Learning that is considered experiential involves reflection, critical analysis and synthesis; opportunities for students to take initiative, make decisions, and to be accountable for the results; opportunities for students to engage intellectually, creatively, emotionally, socially or physically; and a designed learning experience that includes the possibility to learn from natural consequences, mistakes and successes. Kolb’s cycle of experiential learning [1] emphasizes concrete experience, reflective observation, abstract conceptualization and active experimentation. In our course, the laboratory component embodies the concrete experience (and being able to smell and drink your laboratory results doesn’t hurt, either), and reflective observation is enabled by making the connections to traditional chemical engineering. Abstract conceptualization and active experimentation are emphasized in the second half of the course, where the labs are significantly more open-ended. For example, the students are presented with Darcy’s law and asked to design and conduct experiments to test the validity of the law for pressure driven coffee brewing using a manual lever-type espresso device. They have to identify the dependent and independent variables, collect data while varying one of the independent variables and then, of course, taste the results.

In addition to being an excellent instructional tool, especially in the experiential learning context, the course is proving to be invaluable in aiding our outreach and recruitment efforts. Coffee, and making it, is ubiquitous and relatable, and a simple statement to the effect that everything about coffee is related to chemical engineering immediately awakens interest in the basis for that statement, which leads to curiosity about chemical engineering. In this context, we aim to also launch a non-mathematical short course for the general public in the near future.

References:

1. Kolb, David A. Experiential learning: Experience as the source of learning and development. FT press, 2014.