Carolina Saldivar

she/her

Class of 2025

Major: Forensic Science (Chemistry)

Mentor: Susan Oxley, PhD

St. Mary’s University

Comparing three methods to determine acidity in brewed coffee

Coffee is a mixture made up of nonvolatile and volatile compounds which have a sensory appeal.

The purpose of this study is to compare three methods to measure coffee acidity in a brewed

coffee sample. The three methods are titratable acidity to a pH 8, a titration curve with a gran

plot, and HPLC to detect 3-,4-,5-caffeoylquinic acids. The acidity measured using each method

was 71 ± 9 mg/g, 45 ± 3 mg/g , and 27 ±6 mg/g, respectively, where the acidity is reported as mg

CQA per gram of coffee grounds. HPLC resulted in the lowed amount of CQAs because only

CQAs were being analyzed, while the other methods account for all acids in the coffee sample.

Keywords: Coffee, Coffee brewing, organic acids, chlorogenic acids, High-performance

liquid chromatography, titratable acidity