Originally Posted by
alex67500
Don't they also add caramel for colouring (and flavour)?
It's very likely, yes (as far as I know it's never been confirmed, but the colour is highly suggestive of caramel). To be even more pedantic, you won't taste the caramel which is there purely for colour, but as Zacapa 23 has been tested to have >10x the sugar content of some other Caribbean aged rums, it's likely that 20-30g of sugar per litre is added for flavour.