Agricultural rum is an alcohol obtained by fermenting and distilling pure sugarcane juice (the vesou) when industrial rum is obtained by fermenting and distilling molasses (a by-product of the production of cane sugar). 

The different steps of production of agricultural rum are detailed hereafter :

Vesou extraction (crushing)
 

The fresh cane is crushed by a series of crushing mills (3 or 4 usually) to separate the cane juice (vesou) from the fibbers remaining after juice extraction process (the bagasse). The bagasse serves as combustion for the furnaces which heat the water for the boilers and transform it into vapour. This vapour is use in particular to run the vapour machine which activate the crushers and the distilling columns. The vesou is gathered in a drainage system for filtering and pumped on to the fermenting vats.

The fermentation process

During fermentation, which last 24 to 48 hours, the sugar present in the sugarcane is transformed, due to yeast activity, into alcohol. The aromatic elements which will characterize the rum start to appear during the fermentation process. 

A sugarcane "wine" (also called moult) is produced with a 4 to 6° of alcohol.

The moult will quickly be sent for distillation. 

The distilling process
 

The method consist in heating the wine in the aim to vaporize the volatile components, mainly the alcohol, and then to condense them. Before its introduction in distilling column, the wine is brought to a temperature of 70°C.  Introduced into the top of the column, the wine descends by gravity from one plateau to another, heating up when in contact with the steam which is introduced at the bottom of the column.  The alcoholic vapours are then recovered at the top of the column and cooled. A the exit point of the distilling column, the white agricultural rum is colourless and of 70°. The distilling column is the heart of the process. The column give to the rum its own characteristics.

The old distilling column of the Hardy factory, Tartane - La Martinique

The ageing

A portion of it is kept as white agricultural rum and another portion put away for ageing to produce rum known as either "élevé sous bois" (stored in wood) or aged.

White Agricultural Rum : 3 months before bottling, the rum is stored in huge wooden tuns to be "rounded out". It is then brought to desired degrees for commercialization (40° to 62°) with spring water.

Golden agricultural rum or amber agricultural rum : the rum is stored for at least 12 months in wooden containers. Its name is derived from its light golden colour, mostly due to its short period spent in an oak tun. 

Old or aged agricultural rum or also dark agricultural rum : Must be placed in an oak barrel a minimum of 3 years for the VO label (rhum vieux), 4 years for the VSOP label (rhum très vieux) and up to 6 years for an aged vintage XO label rum (rhum hors d'âge). It is the tannin in the wood which bestows the warm hues while the taste is transformed as the years go by.