Dunder
Liquid left after rum distillation, crucial for authentic Jamaican rum flavor.
After a batch of rum is distilled, the liquid left behind in the boiler is called dunder. This substance is a traditional ingredient in Jamaican rum production, used to flavor the next fermentation of the wash. The process is similar to how sour mash is used in Bourbon whiskey, and it is considered essential for creating an authentic rum taste.
Dunder contains various by-products that aid future fermentations, such as dead yeast cells, which serve as an excellent nutrient for new yeast. However, when using dunder in subsequent batches, careful control is needed to avoid stressing the yeast, which can lead to more mutations. If dunder is stored before use, refrigeration is recommended to suppress cell division and prevent these mutations, as they can alter flavor, alcohol content, and the overall consistency of the final product. If not used to repitch the yeast, dunder can also be applied as fertilizer.
Traditionally, between 20% and 35% of a new wash consists of dunder from one or more previous washes. This practice lowers the pH, conserves liquid, provides yeast nutrients, and concentrates key flavoring esters—such as ethyl formate or propyl isobutyrate—known as "rum oils," which ensure a good rum flavor. In the past, after a distillation run, the spent liquid (dunder) was thrown into a "dunder pit," where it would settle and undergo bacterial action that developed these rum oils. The dunder was then taken from the pit as needed to make new wash.
- Traditional proportion in new wash
- 20% to 35%
- Contains
- dead yeast cells, by-products
- Storage advice
- refrigerate to suppress cell division and prevent mutations
- Alternative use
- fertilizer
Lore & Background
Dunder is the spent liquid from the still after distilling a batch of rum. Traditionally, after a run, this liquid was tossed in 'the dunder pit', where it would settle and where bacterial action would develop the rum oils. It was then removed to make wash as needed. In Europe, waste liquors from alcohol distillation are referred to as vinasse.
Reader's Guide
Dunder is significant as a traditional flavor source in Jamaican rum production, similar to sour mash in Bourbon whiskey. It contains many by-products that help in future fermentations, including dead yeast cells which are an excellent yeast nutrient. Traditionally, 20% to 35% of a new wash is dunder from one or more previous washes. This lowers pH, conserves liquid, provides yeast nutrient, and concentrates critical flavoring esters ('rum oils') such as ethyl formate or propyl isobutyrate to ensure good rum flavor. Subsequent fermentations using dunder must be carefully controlled to prevent stress on the yeast, which will cause a greater amount of mutations. These mutations change flavor, alcohol content, and overall affect consistency of the finished product. If planning to store dunder before use, it is advised to refrigerate it to suppress cell division and prevent mutations. Dunder, if not used to re-pitch the yeast colony, can also be applied as fertilizer.
Did You Know?
- Dunder is the liquid left in a boiler after distilling a batch of rum.
- It is similar in process to sour mash in Bourbon whiskey.
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