I've used the TPA Double Chocolate (Dark) & IMO it is very aptly named.In 10ml,5% isn't enough to do much but turn it a light brown and vaped at 80+ watts,can't be tasted.This pissed me off so much I went straight to 10% & this resulted in an almost black juice that reminded me of Bournville chocolate.
Ahh Black juice, i get that when i use Inawera Caramel, never seen anything so dark.