We concluded that the complexity of coffee brews particularly that created by the influence of roasting, precludes using a single assay to adequately describe the antioxidant activity of coffee. Moreover, while chemical assays of free radical scavenging are useful to evaluate the quality attributes of a coffee source, cell-based antioxidant tests are more effective as predictors of bioactive potential that are relevant to human health. The use of PCA in the final interpretation of the data not only allowed for visual displays of the complex relationships among various physiochemical and functional coffee parameters including the CGA isomer content, but also provided an immediate view of the effects of processing and geographic region on each parameter.