To measure the ABV for spirits, you will first need to ensure you have the correct readings using an alcometer and then you can calculate the ABV.

An alcometer is a small float, with a scale in it. The more alcohol that is present, the lighter the density of the liquid and so the alcometer sinks a bit lower. You then read off the scale how much alcohol is present and dilute accordingly.

If the alcometer isn't showing any alcohol - The alcometer works based on the density of the liquid. When we make liqueurs, we add bases which alter the density of the liqueur. This means that now after the base has been added that the alcometer cannot be used to measure the ABV as the density of the liqueur is now not the alcohol alone but has also been affected by the base. It is designed to only measure the ABV of the spirit.

If you do not have access to an alcometer, see below.

Steps to calculate the final ABV of a made-up spirit or liqueur based on any given recipe.

Step 1 is to determine how much alcohol is required in the recipe (we need to determine this before calculating the final ABV of the made-up liqueur). Some flavourings will have this clearly stated in the recipe whereas others won't, but will rather say top up with alcohol to the finished beverage volume or something along those lines. If the latter is the case, please see below:

Volume of alcohol in recipe = Final finished beverage volume - flavouring volume - water volume

Example -  Still Spirits Rhubarb and Ginger Gin Top Shelf Liqueur: 

Volume of alcohol in recipe = 1000 ml - 330 ml - 170ml

Volume of alcohol in recipe = 500 ml

Step 2 is to actually calculate what the final ABV of the made-up liqueur will be. The general formula is as below:

% ABV of made-up liqueur or spirit = % ABV of alcohol called for in recipe X ( volume of alcohol in recipe / final finished beverage volume)

Example - Still Spirits Rhubarb and Ginger Gin Top Shelf Liqueur:

% ABV of made up liqueur or spirit = 40% X (500/1000)

% ABV of made up liqueur or spirit = 20% ABV

Note: The 'volume of alcohol in recipe' is calculated using step 1 if it isn't clearly stated on the flavouring instructions. All instructions will state the '% ABV of alcohol called for in recipe'