Microstructural Evolution of Coffee Beans by High Resolution X-ray Microscopy

Overview

Coffee has become one of the most popular beverages world-wide. But how is coffee made? Coffee beans can be studied to generate new, more effective methods to crush the beans. I studied and took images of different types of coffee beans from Colombia and Ethiopia before they were roasted and after they were roasted using x-ray microtomography. Using the images generated from the microtomography, the differences in microstructure of the coffee bean were studied before and after the roasting process. The heat involved in the roasting process led to a substantial development of pores forming after the bean was roasted. It was discovered that the heat increased size of the pores of the bean, leading to the Volume Fraction of Porosity (%), changing from 5% to 28% in the Colombian Bean, and to 36% in the Ethiopian Bean. Since the Ethiopian Bean was grown at a higher altitude, it had less moisture, likely resulting in larger pore sizes after the roasting process. Since the Ethiopian Bean has less moisture due to the higher altitude of growth, more pores were seen in the bean compared to the Colombian Bean. The aspect ratio of the pores and the diameter distribution were calculated and are discussed.

Competition history

• JSHS 2023 Category not listed

Resources

• National JSHS abstract book ↗

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