RHUM: THE JOURNEY OF SUGAR CANE (PART II)
The climate preferred by sugar cane is hot-humid and for this reason it is cultivated above all in hot tropical countries, where rainfall is very abundant and the temperature rarely drops below 20°C.
The plant generally reproduces by cuttings taken from the top of the stems during harvest and planted in holes about one and a half meters apart to facilitate weeding. The transplant must take place in mid-spring and requires an abundant quantity of water so that, in the following months, the sugar can accumulate within the sap. The ideal soil is clayey-siliceous.
When harvesting the cane called 'zafra' by the Cuban natives, the culm must not be torn, but cut at the bottom generally with a clean blow of a machete, thus leaving the root intact: in this This way the stem will develop again, delivering a new harvest usually the following year.
The cane needs a lot of light to grow, but it also needs a lot of rain and high temperatures during the growth period (35°C); during the ripening period, however, the ideal temperature is 20°C without falling below 15°C. The barrel also resists lower temperatures, but in this case it is subjected to great stress. The risk of frosts with a sudden drop in temperature is one of the problems of sugar cane cultivation in Italy, where a shorter growth cycle of around 6-7 months still allows for an excellent result to be obtained, although with an average higher sugar concentration. low of the Caribbean.
Having drawn up the identikit of sugar cane, we now come to the most important aspect: with 100 kg of sugar cane, how many liters of rhum can you obtain? An average estimate sees the extraction of 70 liters of pure juice for processing 100 kg of cane. If the sugar concentration is 18°brix, an ideal yield of 10% would give us approximately 15 liters of ruhm blanc.
rhums are not all the same and the difference is given by the quality of the raw material, but the type of still and the distillation technique used will also influence their characteristics, for example, while rhums pot stills with double distillation will give a rhum of around 75% vol with an aromatic fraction at least between 200 and 300 g/hl, multiple column stills with continuous distillation will give rise to distillates very rectified, well over 86% vol, and almost neutral in flavor, because without all the characterizing molecules. In fact, the aromas of these latter rhums will derive from the post-distillation processes, but little or nothing from the raw material.
The aromatic expression of a rhum can be modulated during the fermentation phase: short-term fermentations of up to 72 hours will allow the preservation of a prevalence of primary aromas of the sugar cane, longer fermentations of at least 120 hours will lead to to the production of a greater fraction of esters.
Aging must be included in the same perspective of respecting the characteristics of the raw material. Therefore a rhum with not excessively long aging could certainly maintain greater traceability to the work done on the raw material.
Beyond the place of aging of the ruhm, which based on the climatic characteristics will define the evolutionary dynamics, the choice of woods will be a further tool of characterization, in particular ex Bourbon barrels they will give a low release of tannins, giving softness; ex Cognac barrels, will lead towards more tannic and austere rhum.