How Is Rum Made?
Unlike spirits such as Cognac or bourbon, rum is practically declassified, meaning there isn’t a strict system guiding standard production. Therefore, any spirit that contains some form of sugarcane can be called “rum,” and these beverages can range from clear to dark with varying levels of ABV.
That said, there are two main types of rum. Rhum industriel (industrial rum) is made with sugarcane byproducts and usually tastes fruitier. Rhum agricole (agricultural rum), made with the sugarcane juice, is widely considered the signature rum of the French West Indies, and it usually tastes earthier than its industrial counterpart.
Both styles can vary in color, from light to dark, but agricole rums are typically more floral and vegetal and can even be a little funky in flavor. Each island in the Caribbean produces rum differently, but Martinique is the only geographic region with its own appellation d’origine contrôlée (AOC), or “controlled designation of origin,” meaning only specific rum from the French West Indian island can be sold as “AOC Martinique Rhum agricole.”
In general, commercially produced, industrial rums typically start with a base of molasses, yeast and water. During fermentation, the first step of the process, yeast and water are added to the molasses. The strain of yeast (wild, fast or slow) to which the molasses is exposed helps determine the taste and aroma of the rum. The distillery also decides the method of fermenting (natural or controlled), which also affects the timing (anywhere from hours to weeks). After fermentation, the mixture is ready to be distilled. During the distillation process, the fermented liquid is placed in either a column still or a pot still. The liquid is heated to about 175 degrees Fahrenheit, causing the alcohol to evaporate. Distillers collect the vapor from the still and recondense it into the raw spirit.
After distillation, the rum is ready to be aged. The amount of time rum spends being barrel-aged varies, once again, by country and distillery. One year is typically the minimum, but the aging process could last up to decades. Rum is stored in bourbon, wooden or stainless steel tanks or some combination. Rum aged in oak casks turns dark, whereas rum aged in stainless steel tanks often remains colorless. Since a lot of rum is produced in tropical climates, a good amount of the spirit is lost to evaporation, causing it to mature at a faster rate than brandy or whiskey.
After aging, distillers blend the rum to achieve a consistent flavor. During the blending stage, light rums may be filtered to remove any color gleaned during the aging process. With aged rums, caramel may be added for color and flavor, and water may be added to even out the strength.