Is it the tang of the passing of the seasons — and, hence, our own impending demise — that gives pumpkin spice lattes their distinct flavor? The tears of hipster baristas? Actual pumpkin and spices? (AHA HA HA HA no.)
What gives a pumpkin spice latte its distinct notes of flavor is actually a very distinct chemical profile. And as food scientist Kantha Shelke from The Institute of Food Technologists explains, it has very little to do with pumpkin and everything to do with pumpkin pie.
While pumpkin spice latte flavoring is made up of over 340 different flavor compounds — with slight variations depending on which of the dark coffee lords happens to be standing at the caldron at the time — the primary flavors are drawn from the same flavors that make up the top notes of a pumpkin pie.
For cinnamon, pumpkin spice lattes substitute cinnamic aldehydes, for clove or allspice it's eugenol, nutmeg is approximated with sabinene, zingiberene is used for ginger, and often vanillin is added for a dash of vanilla and burned butter flavor, while cyclotene adds a hint of maple.
With this dangerous knowledge in hand, you could even make your own pumpkin spice lattes at home, explains Shelke, substituting the actual spices for their chemical cognates. The result, however, would be something closer to homemade chai.