The adoption of the distillation column is a considerable technical advance to improve the quality of cane brandy.
The first columns were built by Cellier-Blumenthal, a Belgian, between 1808 and 1813, and by the Italian Baglioli in 1815.
An industrial rum plant with two ‘Baglioli continuous machines’ was created in Saint-Pierre by two French merchants in 1818. If the quantity of rum produced is much higher than that of traditional stills, the quality is then less.
Sometime later, a pharmacist named Derosne and his partner Cail bought the Belgian patent and began to manufacture distillation columns.
In 1830, the Irish Coffey filed a patent of still with two columns that allowed to produce alcohol in large quantities.
It was during the second half of the 19th century that the technical improvements of the distillation columns allowed them to prevail. From 1855, the French Armand Savalle and his son, Desire, develop columns for the distillation of molasses that have been adopted both Martiniquais and Brazilians.
In 1867, the French Egrot brought several improvements, and the Germans Pistorius and Siemens proposed similar systems for industrial distillation.
The distillation column allows continuous distillation, unlike traditional stills that were discontinuous. At the end of each distillation, it was necessary to stop production to clean and refill the still. In add, with the traditional still, it was necessary to perform multiple distillation of the drink to reach a level of substantially high alcohol.
Today, the so-called “Père Labat” stills are used very rarely. The discontinuous distillation in a more sophisticated stills, such as Privat, are used for the production of some quality rums.
Used first for the production of molasses rum, the distillation column was adopted for ‘vesou’ rum.
Since the twentieth century improvements have been made but without fundamental technical changes. Improvements mainly take place in the West Indies, so we talk about Creole column. Except for the upper part of the column where the alcohol vapors arrives, stainless steel takes more and more replace copper.
Each column to distill has its peculiarities. Features that contribute to the variety of types of rums produced.
Typically, modern columns produce lighter rum with higher alcohol levels than traditional Creole, Coffey or Savalle columns.
Principle of the distillation column:
The must, still weakly alcoholic, obtained as a result of the fermentation process molasses or cane juice, is pumped to a feed tank located at the top of the column. This bottom serves as a regulator and allows the distillation to operate continuously.
The liquid then passes into a wine heater where the temperature is raised between 65 and 75 degrees before entering the column which contains between 15 and 20 trays.
The stripping section receives in its lower part the vaporized water supply and the fermented must to be distilled in its upper part. The vapours go up through the trays and dabble in the liquid which is going down. While dabbling, the vapours strip alcohol and aromas from the liquid.
There are two separate areas in the column:
- The stripping section of a column is situated below the feed point. Each tray is a level of the column where descending liquid meets the ascending vapours. The vapours get richer in alcohol and aromas and the liquid gets poorer.
- The enrichment section of a column is situated above the feed point. The trays of this section do not handle the liquid fed into the column but rather make the vapour coming from below richer in alcohol.
At the top of the column, the alcoholic vapor is sent to a condenser and a cooler. They are cooled and turned into liquid.
A part of that liquid, called reflux is injected back to the column on the upper part of the enrichment section. This reflux is made of the heaviest compounds (mainly aromatic compounds) of the distilled liquid.
The reinjection of the aromatic compounds helps getting rid of some of the bad tasting ones. The reflux reinjection also allows to reach higher concentration of alcohol by reducing the percentage of non-alcohol compounds.
The higher the column, the lighter the vapor must escape, the more it gets rid of its heavier volatile compounds.
The rum thus obtained at a high alcohol content, more than 70% alcohol by volume. The degree of alcohol is lowered with distilled water.
At the bottom, the stripped liquid gets out of the column. This remaining liquid is called vinasse and is usually from 2 to 3 % abv (4-6 US proof). Vinasse is most often used as fertilizer in the fields of sugar cane. A part can be poured into the fermentation tanks because it serves as a nitrogen and acidic medium conducive to the smooth running of the process.
Multi-column systems produce over 95% very light rums as well as ethanol and agro-fuels.
In multi-columns, the first two or three columns function as single columns. The following columns allow to make adjustments to select or eliminate certain items.