Designing the Future of Cacao
Fermentation: A long-neglected process
Cacao (the primary ingredient of chocolate) derives its flavor from two processes: roasting and fermentation. Roasting was long the focus of improving flavor. This is because cacao can be roasted easily in the chocolate processing centers of Europe and North America, far from its origins.
By contrast, cacao must be fermented while still fresh, on farms in Brazil and other equatorial countries. Fermentation is crucial to developing chocolate flavor, but because it occurs in such regions it has seen little innovation. Beans are still collected in large piles or wooden boxes and left to ferment for several days, mixing only occasionally to improve airflow and consistency.
Our senior capstone design team of four students traveled to a cacao farm in Bahia, Brazil to explore the process. Over a twenty-week senior capstone project, we developed improved methods to monitor and control fermentation to produce better chocolate.
My Role
I studied the geopolitics and economics of cacao farming, wrote technical briefs and grant applications, and I designed graphics used for formal presentations. On the technical side, I also designed the electrical system and wrote the C program controlling it.
The Design of Experiments Approach
Collecting more fermentation data was a top priority for our client and for my team - few farms take any sort of quantitative measurements. Most rely on the look, smell, and feel of the cacao to decide when to mix the beans or end the fermentation.
However, more data is only half the story. While the cacao temperature, pH, sugar, or some other factor at times may predict the cacao quality, that information is useless without some way to manipulate such factors. Therefore the team designed an eight-run factorial experiment to test three of the most commonly varied controls: Mixing, coverage, and drainage.
"Big Data" of Cacao
Once in Brazil, we saw firsthand the challenges of collecting data by hand. Upon returning to Chicago, we developed an automated system to collect data on temperature, sugar, and pH, and to do so more often and more consistently than manual methods.
This data can then be collected and analysed. Over hundreds of fermentations, this data will begin to show what factors affect end quality, when these factors are most significant, and how they can be changed.
An overview of the sensing system. The major sensing components are shown in bold.
Sensors are wired to a central controller, which is inside a waterproof enclosure. Ambient sensors and manual input are mounted to the outside of the enclosure, which sits away from the cacao.
The temperature probes can be slid along the central frame or detached from it entirely to fit differently sized fermentation boxes.
An overview of the sensing system. The major sensing components are shown in bold.
Promoting Global Collaboration
Graphic created by Morgan Uridil, a fellow team member on this project. Used with permission.
Cacao farming remains a very regional process; innovations do not travel readily from farm to farm or country to country.
An automated data collection system can change cacao farming into a global, interconnected network. Standardized data can be collected and shared between farms, and used to experiment on and improve cacao fermentation across the world. This higher-quality cacao can be sold for higher prices, helping farmers to improve their economic situation and to expand their farms sustainably.