Backset

“Backset” is a term used in home distilling to refer to the leftover mash from a previous distillation. When starting a new batch of alcohol, some distillers will use a small amount of this leftover mash in the new recipe.

Why use backset?

The primary purpose of using backset is to control the pH level of the mash. The pH level of the mash affects the fermentation process and the flavor of the final product.

Typically, the pH level of the mash should be between 5.0 and 5.5. Using backset can help to maintain this pH level, resulting in a more consistent and flavorful final product.

Backset is heavily used in rum making, where it adds complexity of flavour over multiple generations. In rum making, backset is called ‘dunder’.

Is backset and dunder the same thing?

Yes, the different terms all mean the same thing, but different terms are used in different distilling traditions. Dunder is the common term when making rum.

How to Use Backset?

To use backset, simply add a small amount (usually 5-10%) to your new mash recipe. Be sure to take into account the alcohol content of the backset when calculating the overall alcohol content of the new batch.

Unique Yeast Usage for Air Stills

There’s no special procedure needed to use backset with an air still. Simply save some of the mash, and use it for your next wash (ferment).

The air still uses a much smaller amount of water than traditional stills, which can lead to a higher concentration of yeast in the mash. This should not heavily influence your backset use, but experiment to get the right ratio.