Nutty
Walnut
bitter walnut skin, earthy
Walnut in chocolate presents as a slightly bitter, tannic, earthy nuttiness: the flavor of the walnut's inner skin rather than the sweet meat. It can add complexity and depth but occasionally tips into an astringency that some tasters find challenging.
What Causes It
Tannins and certain phenolic compounds in both cacao and walnut share a family resemblance. Over-roasted beans or under-fermented cacao can express this bitter walnut quality. It is more common in darker bars where astringency is less masked by sugar.
Where to Find It
Some Dominican Republic and Haitian origins show this note, particularly at higher percentages.