
Chocolate bitters are concentrated cocktail bitters flavored with cacao and aromatic botanicals, dashed in to season a drink — cocoa bitters are the same thing under another name.
A few dashes add cocoa and bitterness without adding volume. They sit well with aged spirits, coffee and banana, and in stirred drinks like a Negroni or an Old Fashioned.
Another chocolate bitters
Works dash for dash. Bittermens' Xocolatl Mole adds cinnamon and other spices, and Fee Brothers' Aztec Chocolate is only 2.5% ABV.
Aromatic bitters
Without chocolate bitters, Angostura or another aromatic bitters gives the bitterness but not the cocoa.
Chocolate liqueur / crème de cacao
Sweet and weaker than bitters: a barspoon stands in for two dashes and adds sugar as well as cocoa.
It separates and it settles, and both are normal — the cocoa particles are suspended rather than dissolved. Give the bottle a slow turn before use. Nothing about the flavor changes appreciably with age.
Double Black
Cacao & coffee spiced rum, Crème de Café liqueur