Although it appears to be somewhat unoriginal at this point, one of my favorite organic molecules is caffeine. Its purest form is mildly different from the great coffee drinks I would normally associate it with in that it is actually a white powder and very bitter to the taste. It is found both in nature in certain seeds, leaves, and fruits but can also be synthetically made in a lab. The world’s primary source of caffeine is the coffee bean.
The historic time period when coffee was discovered is ambiguous, but where most sources agree is that it dates back years and years to around the 15th century and possibly even earlier. Legend has it that a goat herder in Ethiopia observed his goats full of energy after eating berries from a certain tree. After reporting the bizarre behavior to his local monastery, a drink was prepared with those same berries yielding similar results (alertness etc.) Slowly the news of the strange and energizing concoction broadened and a hop and a skip later there’s a Starbucks on every street corner! And it’s a good thing too, because coffee wards off sleepiness and helps restore mental alertness as it is a central nervous system (and metabolic) stimulant. Regular coffee consumption has also been correlated to a reduction in the risk of developing Parkinson’s disease (although correlation does not mean causation!).
Something really interesting about coffee and that I’m sure a lot of us are familiar with visually is the “coffee ring effect.” Although these structures seem like they form due to the outline of our mugs or cups or whatever, it’s actually a pretty specific process, meaning that the different sized particles of coffee on any surface rearrange themselves into separate rings by size- with the smallest particles out nearer to the edge. So picture a drop of coffee hitting a surface- the drop’s rim is held down to the surface and cannot move. The water is evaporating and the pinned drop flattens out, pushing water from the center out toward the stuck rim. As it’s doing this the water is also moving all the coffee grinds along with it which linger behind after the water evaporates, forming a rim. This is just another example where scientific worlds merge; purine-structured caffeinated coffee grounds on the one hand and physics on the other.
A fun fact I discovered while working on this is that caffeine is also embedded to the literature world of the 18th century, in that the first chemist to synthesize it in 1812 - Friedlieb Ferdinand Runge – was given Arabian mocha beans by Johann Wolfgang von Goethe, one of the world's greatest poets. Goethe asked Runge to perform the analysis, and the conclusion derived from this request was the world's first pure caffeine sample.