What is the difference between Rum and Rhum? And no it isn't just the extra “H” added after the “R”. The difference is down to what is used as the base for fermentation and the two are actually very different types of spirit, with different flavours and smells.
Rum is an overarching term for any spirit distilled from fermented sugarcane products. Generally however when talking about Rum, most people will be referencing the style made popular by the British. This is a spirit distilled from fermented molasses, a byproduct of the sugar production process. The more technical term for this kind of rum is Demerara Rum.
Demerara Rum has some very bold and distinct taste profiles, including caramel, vanilla and honey. Certain tropical fruits and spices can be present as well in addition to the bold “rummy” flavour present due to the molasses used as a base for fermentation.
Rhum is a more specific term used to describe a spirit distilled from fermented sugarcane juice. The juice is pressed out of the raw sugarcane and is then used as the base for fermentation. This type of spirit was made popular by the French and it was developed in the French colonies where sugarcane was grown. Rhum is actually an abbreviation for Rhum Agricole, agricole meaning agriculture.
Rhum Agricole tends to have a completely different flavour profile to Demerara Rum. These flavours will tend to be lighter with more grassy and floral notes coming through. Because the sugarcane juice itself is used as a base for fermentation, it is possible to pick up different terroir in the flavour of Rhum Agricole.
By changing what is being fermented, Molasses or Sugarcane juice, two very different spirits can be created. With the differences between Rum and Rhum, the potential for interesting and flavourful drinks is nearly endless.