: This laboratory experiment challenges students to identify the
country of origin of raw coffee beans from around the world by calculating the
percent caffeine and percent water in the supplied samples. The implementation of
this experiment enables students in introductory chemistry classes to gain greater
understanding of the chemical analysis process and the Beer−Lambert law. Using
commercially available raw (green) coffee samples, students extract caffeine from
the grounds as an aqueous solution and determine the percent caffeine using UV−
vis spectrophotometry. In a second portion of the experiment, raw beans are
roasted to determine the percent water content. Using both pieces of data,
students are asked to identify the country of origin of given coffee samples in
which the percent caffeine ranged from 1.14 to 1.80% (w/w) and the percent
water loss ranged from 3.27 to 10.8% (w/w).