Taking its roots in the Caribbean Islands, rum is largely made from molasses, a by-product of sugarcane industry. All rum is clear after fermentation, but dark rum gets its color from aging in barrels or having caramel and sugar added. Light rums have a shorter fermentation making them slightly sweet and better for mixing, while dark rum is usually fermented longer and produces a richer spirit. Spiced rum gets much of its flavor from herbs and spices that steep into the rum.