MAKING RUM
Rum is an aromatic spirit that’s distilled in a pot still, or a reflux still operated in a low-separation mode. The distillation process is the same as that for whiskey, except rum is distilled from a cane-sugar substrate, whereas whiskey is distilled from grain mash. After distillation, the rum is diluted and infused with burnt sugar (i.e. caramel) to give it its characteristic dark-rum flavour and colour. Some rums are oak aged before they are infused with burnt sugar.
The intensity of the rum flavour is a function of the proportion of molasses in the mix. Straight molasses and water would yield a very rich, intense rum flavour. Whereas, say ¼ molasses and ¾ white sugar would produce a much milder-flavoured rum. Individual distillers can adjust the proportions of molasses and sugar to their preference. Also, raw cane sugars such as demara, turbinado, or simply “brown sugar” are types of sugar that still have molasses mixed in them in varying proportions, and are widely used to make rum. However, most distillers find that blending molasses and white sugar affords better control over the proportion of molasses.
To make rum on a small scale, a home-distiller or micro-distiller can ferment a mixture of molasses, sugar, and water and distil it as an aromatic spirit, then add some caramel made by boiling sugar and water until it burns to a deep, dark brown colour. A recipe for a medium-bodied dark rum follows.
Ingredients
• 6 gal (23L) Warm water
• 6 Lbs (2.75K) Fancy molasses (i.e. good quality table molasses)
• 4.5 Lbs (2K) White sugar
• 10-tsp (50g) Diammonium phosphate (DAP), or Distiller’s Nutrient
• 6-tsp (30g) Whiskey yeast, or 1 pkg of whiskey yeast for 25L
Method
Place all ingredients except the water and the yeast in a 7.5 gal (30L) fermenter. Add 3 gal (12L) of warm water and mix thoroughly to dissolve the ingredients. Fill up the fermenter with water to 6 gal (23L). The SG should be about 1.070. Ensure the temperature is under 100 oF (38 oC) and mix in the yeast. Keep the fermenter lightly covered (i.e. such that the CO2 pressure can escape) and in an ambient temperature of between 80 and 90 oF (27 and 33 oC).
Fermentation should take 7 to 10 days. The SG at the end of fermentation (i.e. after bubbling stops) should be about 1.000 or less.
Siphon the clear liquid off the sediment into a pot still, or whatever still you will be using. Do a crude beer-strippping run on it and continue the distillation until the total distillate received (i.e. low-wines) is down to 25% abv.
Clean the still out thoroughly, and place the low-wines back in the still. Bring the still to boil at a heat level suitable for running off an aromatic spirit.
When the distillate begins to run, receive the first spirit (i.e. heads) into a receiver labeled “Heads”. Begin smelling a tasting the spirit right away, and when the ester and acetone smell and taste subside, begin-cut to the hearts phase. Switch to a separate receiver for the hearts. This begin-cut will take place at between 80 and 85% abv, depending on the still.
Continue to smell and taste the spirit periodically as it’s dripping out of the still during the hearts phase, and monitor the still-head temperature. As the temperature tops over 90 oF (33 oC), watch out for taste changes in the flavour of the spirit. Towards the end of the hearts phase, the spirit will start losing its sweetness and begin taking on a grainy, unpleasant flavour. This is the point where the run is end-cut to the tails phase. Switch the receiver to a tails collector. The end-cut will typically take place when the evolving distillate is at about 65%, and the head temperature is around 92 oF (33.5 oC).
The hearts phase is the rum and it will be between 70 and 77% abv. Dilute the rum to bottling strength (i.e. 40 or 50% abv), and begin preparing the caramel.
To make the caramel, mix about 3.5 ounces (100g) of white sugar with enough warm water to dissolve it, then bring it to boil. Simmer the mixture gently until it begins to turn yellow. Continue to simmer but watch the colour change carefully. The colour will become a deeper yellow, then brown, then dark brown. For rum the caramel must be burnt much darker than for candy apples, or other applications of caramel. When it’s a light brown colour, take it off the heat and continue to watch the colour change. When the caramel is a very dark brown, almost black, cool it in cold water to halt the burning. When cooled, this caramel will be a very dark, hard, glassy sugar crystal.
Dissolve the caramel in the rum until the colour of the rum is at the desired level. For example, for an amber rum there should be enough caramel to give the rum the characteristic amber colour. For a navy rum or black rum, add enough caramel to render the rum very dark, almost opaque.