The coffee ring could be a new test for drinking water quality. Tap water leaves distinct patterns and whorls its dried residue, like a coffee ring. The markers indicate water hardness and alkalinity, as well as the presence of dissolved solids and metals.
Researchers at Michigan State University hope the ‘Coffee – Ring Effect’ will provide an inexpensive and accessible way for people to identify traits in their drinking water.
Photo: Yuto Ooi et al. CC- Modified from http://www.tandfonline.com/…/…/10.1080/14686996.2017.1314776