The devil's own coffee.

Starbucks SKU # 666 corresponds to one pound of Italian Roast.

I found this particularly interesting for a few reasons:

-Italian Roast is one of our more darkly roasted coffees. In other words, the beans spend more time in the fire. Fitting for one whose time is spent in the vast pits of flames believed to fill Hell.
-Dante Alighieri, whose personal interpretation of the devil, as shared in his Inferno, is a commonly accepted portrait of the one called Satan, was Italian. Florentine, to be exact.
-Rome, the seat of the Pope and the heart of Catholicism as well as Christianity, is in Italy. I need not elaborate on this irony.

These are all of the connections I can make at this time. Italian Roast being a coffee of high intensity, intricate boldness, and decadent sweetness (compared to the smokiness of French Roast), it seems an appropriate choice for Lucifer.