Outside a café, a chalkboard sign makes a joke: "Not to get technical... but according to chemistry coffee is a solution!!" It's a good line, and it's partly true. Whether it's right depends on which coffee you're holding. A cup of filter coffee is very close to a true solution. An espresso is a mix of several things a chemist would file under different headings, and that mix … [Read more...] about Is Coffee a Solution? Filter Coffee Mostly Is, Espresso Only Partly