Rum is a distillate made from molasses or sugar cane juice, and by law it must have a minimum alcohol content of 37.5%. This is where the general definition ends. There are many varieties that differ in name, method of production and country of origin. The production process is similar, regardless of whether molasses or sugar cane juice is used.
The following production steps lead to the finished distillate:
After harvesting, which is usually still done by hand, the pulp is separated from the stalks. It is then cooked and finally processed into sugar syrup (molasses) by centrifugation.
Molasses
Molasses is a by-product of sugar production. In this process, the juice is pressed from the cut sugar cane and boiled down to such an extent that sugar crystals form. Syrup and sugar crystals are separated and the by-product of sugar is called molasses.
Most (about 90 per cent) of the world's rum is a distillate of molasses.
Sugar cane juice
Rum, or rhum, made from sugar cane juice is called rhum agricol. This is a variant of rum from so-called 'agricultural' production. Rhum Agricol only has a market share of about 5 per cent.
The syrup is diluted with water and yeast is added. This starts the biological process of fermentation, in which the yeast breaks down the sugar and converts it into alcohol. The result is an alcohol content of 5-6%.
Traditional rum is made with wild yeasts. These are yeasts that are naturally present in the air and settle on the mash. However, this process is not as arbitrary as it sounds at first. In order for a deliberate strain of yeast to form and settle, there are walled and poorly ventilated rooms in distilleries to grow and store the yeasts.
Alternatively, and especially for the mass market, brewing ovens are used.
The fermentation time varies greatly between hours and weeks. A very long duration of the process promotes the formation of many esters that give the rum a unique taste. This is called high ester rums.
The fermentation process takes place in huge barrels made of concrete, steel or wood.
The fermented sugar cane juice or molasses syrup is heated in a distillation unit and the resulting alcohol is extracted by cooling. An alcohol content of up to 95% is produced.
Distillation in column stills is common. However, distillation is also carried out in pot stills.
The storage traditionally takes place in oak barrels that previously contained whisky or wine. The duration can vary from a few months to several years. In principle, rum does not have to be stored to be called rum.
If a rum is not stored, we speak of white rum. This is reduced to the desired drinking strength after distillation. It is therefore very young and unripened and is preferably used for mixing cocktails and long drinks. The drinking strength is at least 37.5 percent, for so-called overproof rums 57.15 to 70 % vol.
Rum that has been aged is called brown rum. Here, the rum is filled into wooden barrels after distillation and left to mature. It usually goes into barrels without being diluted beforehand and has an alcohol content of 75 to 95 % vol. at this point. The storage time ranges from about six months to a few decades.
In addition, rum is matured in the so-called solera process.
The bottling of rum is very diverse. Several batches from one distillery, but also rums from different distilleries, can ultimately be bottled. Here, the rum is diluted with water to the desired drinking strength. The only thing to bear in mind is the minimum 37.5% alcohol by volume required by law.
