Liqueur sweetening calculator

How to use it

1. Enter the spirit. Its volume and strength - measured before anything sweet goes in, because sugar stops an alcoholmeter reading correctly.
2. Choose the strength. Most fruit and cream liqueurs sit between 15% and 30% ABV; herbal liqueurs often higher.
3. Choose the sweetness. In grams of sugar per litre of liqueur. Around 100 g/L is just sweet; 250 g/L is a rich crème; 400 g/L is as sweet as crème de cassis. Tap the ticks to try them.
4. Choose how to sweeten. Plain sugar dissolved in the water gives the most room for flavour. Syrup is easier to mix but brings its own water - the calculator allows for it.
5. Add any other liquid. Juice, cream, an infusion or coffee: enter its volume and it is counted as part of the water.

How it works

The alcohol in your spirit doesn't change, so the volume of liqueur follows directly from the strength you want: one litre at 40% makes 1.6 litres at 25%. The sugar is the sweetness times that volume.

Dissolved sugar takes up room - about 0.63 litres for every kilogram - so the calculator subtracts that from the volume, works out the water that brings the alcohol and water to the right strength (using the OIML density tables, so the shrinkage when they mix is allowed for), and then takes away any water already coming in with the syrup or other liquids. If they bring more water than the recipe needs, it tells you what strength you'll end up with instead.

Worked examples

1 litre of 40% spirit made into a 25% liqueur at 250 g/L takes 400 g of sugar and 350 mL of water, and makes 1.60 litres. Made with simple syrup instead, the syrup alone brings 400 mL of water - more than is needed - so the liqueur would finish at about 0.5%: use rich syrup or plain sugar.

A 700 mL bottle of 40% vodka made into a 20% crème at 300 g/L needs 420 g of sugar and 436 mL of water, for 1.40 litres.

Questions

How sweet should a liqueur be?

It's a matter of taste. In the EU a drink must have at least 100 g of sugar per litre to be called a liqueur (a little less for a few kinds), 250 g/L to be a crème, and 400 g/L for crème de cassis.

How strong should a liqueur be?

Usually 15–30% ABV. In the EU 15% is the minimum for a liqueur. Stronger keeps better; weaker lets delicate fruit come through.

Why can't I measure my liqueur with an alcoholmeter?

Sugar makes the liquid denser, so the alcoholmeter floats higher and reads far too low. Measure the spirit before sweetening and trust the sums.

Sugar or syrup?

Either gives the same sweetness. Syrup mixes in more easily; plain sugar, dissolved in the water you would add anyway, leaves more room for juice and other flavours.

Why did my cream liqueur separate?

Cream needs enough alcohol and sugar to stay stable, and it keeps best cold. Fresh cream liqueurs belong in the fridge and are best drunk within a few weeks.