Fall is absolutely a season for brown inks. Cacao du Brésil is a grayish brown by Herbin that indeed slightly resembles cacao. Decent and low-key enough for the workplace but with enough character for personal correspondence and notes.
A well-behaving ink as expected by Herbin. No feathering, hardly any show-through, good lubrication and not very wet. The ink has some nice shading. Drying times were below average (little over 25 sec). Water won't wipe out your writing immediately, but water resistance is low at best.
Compared to other browns Iroshizuku's Yama-guri and Diamine's Macassar are a lot darker, deeper brown and more saturated. Herbin's Café des Iles is significantly less dark and more red.
All in all this is a very nice brown ink!
Written on Original Crown Mill Vellum paper