Most rums are made from molasses (a by product of the sugar industry) although rhum agricole is made from sugar cane juice.
Sugar cane is cut either mechanically or by hand and must be transported quick sharp to a sugar mill as the sucrose (sugar) levels start to fall from the moment the cane is cut.
The sugar cane is then crushed and the juice extracted to make a syrup. This syrup is boiled until sugar crystals are formed, when the sugar crystals are removed – a thick black residue, known as molasses, is left.
The molasses are so highly concentrated in sugar it is impossible to ferment as is, as the yeast would not survive such hostile conditions. The molasses are therefore diluted with water prior to fermentation. A yeast is then added, and much like bourbon each rum distillery will have its own strain of yeast which they feel impacts on the final flavour profile of the rum. This molasses mixture is fermented to produce an alcoholic wash of around 10% abv. Light rums will be fermented quickly (around 24 hours) and heavy rums will enjoy a longer ferment.
Approximately 2.5kg of molasses will give 1 litre of rum at 57% abv.
Light rums are distilled using column stills, either single column, coffey stills or multiple linked column stills.
Traditionally pot stills were used to make heavier rums, although not as many producers use pot stills nowadays. Rums from pot stills were used to give weight to blends especially for Navy style rums. Although the current revival in fuller bodied spirits led by the thirst for malt whiskies is increasing interest in heavier pot still rums.
The majority of rum pot stills, use retorts to ensure a higher strength spirit from a single distillation. Retorts are copper vessels that contain the leftover high and low wines from the previous distillation to create additional flavours.
Alcohol boils as at lower temperature (78.3° C) to water 100° C. So when the pot still is heated, alcoholic vapour will be released before water is, it passes into the low wine retort, a second copper vessel which contains an alcoholic mix of low wines and water. The hot vapour passing through, boils the liquid in the retort, releasing its most volatile components. This vapour is now more concentrated in flavour and is carried through to the high wines retort, where the process is repeated. The vapour is now high strength and is condensed. By adjusting the composition of liquids in the low and high wines retorts, a distiller can create a range of different flavours.
After a short heads run, the heart of the spirit is collected at 85% abv, the next part of the spirit is the low wines and finally the high wines. Both the low and high wines are collected to fill the retorts for the next distillation.
Blending is a key part of the rum making process and many of the best golden rums blend a number of different distillates to create a more complex rum.
The distillation process in Guyana is even more complicated and includes the use of pot stills made from greenheart wood, with a copper neck. A double pot still from Guyana will include two wooden pots, a retort with a rectifier attached and a condenser.
The copper neck of the first pot goes into the body of the second pot and both are filled with an alcoholic wash of approximately 10% abv. When they are about to boil, the steam is taken off the second pot and the vapour from the first pot, which comes over the neck, boils its wash. The second pot’s neck leads to a retort (filled with low wines, high wines etc, depending on the mark of rum being created), then to a rectifier and a condenser. The resulting rum is the weightiest mark of all: deep and powerful with aromas of black banana and overripe fruit.
Styles of rum:
White rum is light-bodied, usually unaged and distilled in column stills or may like Bacardi be aged and then filtered to remove the colour.
Golden rum is medium bodied and off dry, can be distilled in a column or pot still – or a mixture of the two. These rums gain some colour from oak ageing, which can be enhanced by the addition of caramel.
Spiced rum are often golden rums infused with vanilla and spices – and are proving very popular – according to the Drinks Business today – ‘the spiced rum category is on fire!’
Dark rum are full bodied rums, often sweetened.
Did you know? Navy strength rum was traditionally bottled at over 57% as this is the strength that if rum was spilled into a barrel of gunpowder, it would be strong enough to allow the gunpowder to ignite even when wet.
Rum has four distinct flavour camps which historically have been linked to different regions.
Light, delicate, clean rums characterised by Cuban rum’s like Havana Club and Bacardi which was originally made in Cuba. These rums are have light citrus notes when young and develop more fresh tropical fruit flavours with age. This delicately flavoured style is emulated in many other regions like the Bahamas, Puerto Rica and Trinidad.
In 1862 Don Facunado Bacardi Masso was the first to produce rum made using continuous stills in the Caribbean on the island of Cuba. By 1930s, Bacardi had expanded to produce rum in Puerto Rica and Mexico and today is no longer produced in Cuba, but with Havana Club still represents the Cuban style.
Jamaica – long sea-faring connections, largely pot stilled, if continuous stills cut a lower level.Pungent estery rums in white, golden and dark forms. Classic example is Wray & Nephews’ Appleton Estate.
Jamaica’s pot still rums are graded by the concentration of esters (volatile, acetic aromas). The lowest level are called ‘common cleans’ and have a delicate, slightly floral note, next is ‘plummers’, which have slighter higher concentration and a light tropical fruit character. ‘Wedderburns’ are fuller in flavour with more body, deeper fruit character, and increased pungency and lift.
The ‘high esters’ are the most pungent level of all. When neat, these aromas can come across as gloss paint or nail polish – not exactly what you’re after in a rum, but when heavily diluted this nose burning intensity is replaced with concentrated aromas of pineapple and banana. Rum blenders use them as a whisky blender might use a heavily peated malt.
High ester rums may have started life with an extended 14 day fermentation. In addition ‘dunder’ will have been added to the fermenter. A dunder starts life as the acetic residue left in the bottom of the still similar to a Bourbon backset. In Jamaica, the dunder is put into pits outside and allowed to fester to boosts its acidity. In all of these rums, the wash is then run through a pot/retort system and varying the contents of the retort will help create new complex flavours.
Barbados was one of the first countries to produce commercial rum and by 1776 Barbados had produced 3 million gallons of rum. Barbados’ elegant, fruity style is characterised by Cockspur and Mount Gay and has a fruity balance and medium weight – there is often some rich distillate in the blend.
On the coast of South America, Guyana produces spicy dark rums that are lighter in body than Jamaican rums but have pungent, dark sugar, fruit cake aroma and taste. They used to be used more as a base of Navy rums but Demerara Distillers is now producing some Guyanese brands which are receiving international recognition – El Dorado – which is a darn beautiful rum in my book.
Martinique and Guadelope – specialises in Rhum Agricole, a grassy fruity style of rum made from fermented cane juice not molasses. The juice from sugar cane is extracted and fermented relatively quickly to create a wash of between 4.5 and 9%, which is then distilled in single column still a la Armagnac to create a low strength spirit between 65-75%.
Agricole is pungent and vegetal when young with aromas of cane, green leaf , apple, unripe banana, anise and violet backed up by a slightly oily texture.
Most is sold young as unaged rhum blanc, designed to be mixed, although a small amount of aged. If aged for 18 months it is known as ambre or paille, if aged for at least three years it will be called vieux.
Whereas in Brazil, Cachaça is popular, this is a cane based unaged spirit usually distilled in a mix of pot and column stills depending on the style, and will have similar vegetal knots as Rhum Agricole. Traditional pot still and single column distilled cachaça are the most vegetal in style and have been distilled to a lower strength. Some high strength, filtered cachaça are trying to emulate the success of vodka and are more neutral in style.