October 1 marks International Coffee Day. We’ve looked at various aspects of coffee chemistry on the site previously, but haven’t yet looked at the key divide between coffee beans: arabica and robusta. This graphic looks at the two types of coffee beans and some of their chemical differences.

If this leaves you wondering more about coffee chemistry, one of the older posts on the sites deals with the sources of bitterness in coffee. There’s also this post on the compounds that contribute to fresh coffee’s aroma, and the most recent post which looks at how coffee can be decaffeinated.