Wired has a fascinating look at the chemicals at play in your daily espresso.
Here’s my favourite part of the chemical equation (if you thought caffeine you were wrong):
Trigonelline
Chemically, it’s a molecule of niacin with a methyl group attached. It breaks down into pyridines, which give coffee its sweet, earthy taste and also prevent the tooth-eating bacterium Streptococcus mutans from attaching to your teeth. Coffee fights the Cavity Creeps.