To make a liqueur at home you buy four things: alcohol, sugar, water and the flavorings, meaning peels, herbs, spices or fruit. The first three decide the strength. Below are the amounts for making the same limoncello at 28%, 35% or 40% ABV, how they change if you want it sweeter or drier or use vodka, and the calculation for any recipe of your own.
What decides the strength of a homemade liqueur?
Three of the four ingredients. The alcohol brings all the pure alcohol the liqueur will have; the water and sugar dilute it. Flavorings barely count: peels, herbs and spices add aroma and almost no liquid. Juicy fruit is the exception, because it releases its juice.
- The alcohol. The label gives the strength, and the strength tells you how much pure alcohol is inside. A liter of 95% alcohol (190 proof) holds 950 ml of it, a liter of 40% vodka (80 proof) holds 400 ml. That is all the alcohol the liqueur will ever have.
- The water. It is the water you make the syrup with, and it is the main lever: more water, lower strength.
- The sugar. It decides the sweetness, but once dissolved it takes up space too: 800 g becomes about half a liter. So it lowers the strength just as half a liter of water would.
- The flavorings. In limoncello they are the zest of 8 to 10 lemons. They steep in the alcohol and are strained out: they play no part in the calculation.
How much sugar and water for a 28%, 35% or 40% limoncello?
With 1 liter of 95% alcohol: for 28% ABV, 1 kg of sugar and 1.75 liters of water; for 35%, 800 g of sugar and 1.2 liters of water; for 40%, 700 g of sugar and 950 ml of water. The amounts keep the same sweetness, about 300 g of sugar per liter of liqueur, so only the strength changes.
| Target ABV | 95% alcohol | Sugar | Water | Limoncello you get |
|---|---|---|---|---|
| 28% (56 proof) | 1 L (33.8 fl oz) | 1 kg (5 cups) | 1.75 L (59 fl oz) | ~3.4 L |
| 30% (60 proof) | 1 L | 950 g (4 3/4 cups) | 1.55 L (52 fl oz) | ~3.1 L |
| 32% (64 proof) | 1 L | 900 g (4 1/2 cups) | 1.4 L (47 fl oz) | ~3 L |
| 35% (70 proof) | 1 L | 800 g (4 cups) | 1.2 L (41 fl oz) | ~2.7 L |
| 40% (80 proof) | 1 L | 700 g (3 1/2 cups) | 950 ml (32 fl oz) | ~2.4 L |
In every version the zest of 8 to 10 lemons steeps in the liter of alcohol. The sugar and water become the syrup you add after steeping. The 35% row is the liquori.it reference limoncello, which also gives the timings and steps. With half a liter of alcohol, halve every amount.
The lower the strength, the more liqueur the same liter of alcohol makes: at 28% you get almost a liter more than at 40%. It is the same alcohol, spread over more bottles.
In the United States, 95% alcohol is sold as 190-proof grain alcohol, and only in some states. A liter of 151-proof (75.5%) holds 755 ml of pure alcohol: put that figure into the first step below and the rest of the calculation stays the same.
Where the 35% comes from
The calculation takes three steps, and it works for every row of the table:
- Pure alcohol. 1 liter of 95% alcohol holds 1000 × 95 ÷ 100 = 950 ml of pure alcohol.
- Total volume. Add up the ingredients: 1000 ml of 95% alcohol, 1200 ml of water and 500 ml of dissolved sugar (800 g ÷ 1.6). 2700 ml in all.
- ABV. 950 ÷ 2700 × 100 = 35.2: the limoncello is about 35% ABV.
For the 28% version: 1000 ml of 95% alcohol, 1750 ml of water and 625 ml of dissolved sugar (1 kg ÷ 1.6) make 3375 ml. 950 ÷ 3375 × 100 = 28.1.
What if you want it drier or sweeter?
Change the sugar and adjust the water, because dissolved sugar takes up volume. To stay at 35% with 1 liter of 95% alcohol: with 550 g of sugar you need 1.35 liters of water, with 1.1 kg only 1.05 liters.
| Sweetness | Sugar | Water | ABV |
|---|---|---|---|
| barely sweet, ~200 g per liter | 550 g (2 3/4 cups) | 1.35 L (46 fl oz) | 35% |
| ~250 g per liter | 700 g (3 1/2 cups) | 1.3 L (44 fl oz) | 35% |
| classic, ~300 g per liter | 800 g (4 cups) | 1.2 L (41 fl oz) | 35% |
| ~350 g per liter | 950 g (4 3/4 cups) | 1.1 L (37 fl oz) | 35% |
| very sweet, ~400 g per liter | 1.1 kg (5 1/2 cups) | 1.05 L (35.5 fl oz) | 35% |
The same holds at every strength: each extra 100 g of sugar takes about 60 ml of water out of the syrup, which is the space it fills once dissolved.
What changes with vodka in place of 95% alcohol?
A liter of 40% vodka holds 400 ml of pure alcohol, less than half of a liter of 95% alcohol, and the syrup always brings the strength down. With the sweetness of a classic limoncello you top out at around 32%, and 40% with sugar is impossible: that is already the strength of the vodka on its own.
| Target ABV | 40% vodka | Sugar | Water | Limoncello you get |
|---|---|---|---|---|
| 25% | 1 L (33.8 fl oz) | 450 g (2 1/4 cups) | 300 ml (10 fl oz) | ~1.6 L |
| 28% | 1 L | 400 g (2 cups) | 200 ml (6.8 fl oz) | ~1.45 L |
| 30% | 1 L | 400 g (2 cups) | 100 ml (3.4 fl oz) | ~1.35 L |
With vodka you get less than half the liqueur the same liter of 95% alcohol makes, and the syrup is made with very little water. The differences in flavor and the method are in the article on limoncello made with vodka.
How do you work out the volume of the dissolved sugar?
Divide the weight of the sugar by 1.6. Dissolved granulated sugar takes up about 0.63 ml per gram: 800 g becomes about 500 ml, a kilogram about 625 ml.
| Sugar | Volume once dissolved |
|---|---|
| 400 g (2 cups) | ~250 ml |
| 600 g (3 cups) | ~375 ml |
| 800 g (4 cups) | ~500 ml |
| 1 kg (5 cups) | ~625 ml |
This is the step many recipes skip, adding up only the alcohol and the water. In the limoncello that means counting 2.2 liters instead of 2.7, and getting 43% instead of 35%. Depending on the source, the specific gravity of granulated sugar is between 1.59 and 1.625: either value changes the result by less than 1%, so at home 1.6 is enough. It is the figure used in every liquori.it recipe.
How do you work out the amounts for any liqueur?
Start from the strength you want. Divide the pure alcohol by that strength and multiply by 100: that is the total volume the ingredients need to reach. Take away the alcohol and the volume of the sugar: what is left is the water to add.
For example, a 30% herbal liqueur with half a liter of 95% alcohol and 300 g (1 1/2 cups) of sugar. The pure alcohol is 500 × 95 ÷ 100 = 475 ml. The total volume needs to be 475 ÷ 30 × 100 = 1583 ml. Take away 500 ml of 95% alcohol and 188 ml of dissolved sugar (300 g ÷ 1.6) and you are left with about 900 ml (30 fl oz) of water.
If the recipe has other liquids, such as juice, milk or wine, take them off the water too. ABV, alcohol by volume, is the number of milliliters of pure alcohol in 100 milliliters of the drink, the percentage printed on every bottle. In the United States proof is twice that number. European rules measure both volumes at 20 °C (68 °F). The whole process, from steeping to resting in the bottle, is in the complete guide to making liqueur at home, and the syrup method in the guide to sugar syrup for liqueurs.
How do you adjust the ABV of a finished liqueur?
If the liqueur is too strong, add water or syrup; if it is too weak, add 95% alcohol. Either way, start from the current ABV worked out with the three steps, decide the strength you want and calculate how much to add. Fix a small sample first, taste it after a few days, and only then adjust the whole bottle.
If the liqueur is too strong
Divide the pure alcohol in the liqueur by the strength you want and multiply by 100: that is the volume the liqueur needs to reach. The difference from the current volume is how much to add.
With the reference limoncello, 2.7 liters at 35% with 950 ml of pure alcohol, bringing it down to 30% means reaching 950 ÷ 30 × 100 = 3167 ml: you need about 470 ml (15.9 fl oz) more. If you add plain water, though, the sweetness drops too: the sugar goes from 296 to 253 grams per liter, and the liqueur ends up drier than intended.
To keep the same sweetness, add a syrup with the same sugar concentration as the liqueur. In this example that is 140 g (about 2/3 cup) of sugar dissolved in 380 ml (12.8 fl oz) of water: you reach 30% with 297 grams per liter, practically unchanged. The general rule is to multiply the liters you need to add by the grams of sugar per liter in the liqueur, and dissolve that much sugar in enough water to make up the volume to add.
If the liqueur is too weak
Add alcohol, with this formula: alcohol to add = liqueur volume × (target ABV − current ABV) ÷ (alcohol strength − target ABV).
To bring 2 liters (67.6 fl oz) of liqueur from 25% to 30% you need 2000 × 5 ÷ 65 = 154 ml (5.2 fl oz) of 95% alcohol. Where 190-proof grain alcohol is not sold, 151-proof (75.5%) does the same job with 220 ml (7.4 fl oz). The same fix with 40% vodka would take a whole liter, stretching the liqueur by half and watering down its flavor, which is why it is not a practical choice for raising the strength. The added alcohol lowers the sweetness a little, by 7% in this example, which you usually cannot taste. The guide to choosing the alcohol compares the options.
How to go about it
Measure out a set amount, say 100 ml (3.4 fl oz), and adjust it in proportion. A freshly mixed liqueur tastes more of alcohol than it will after a few days of rest, so taste the sample after two or three days. If you like the result, apply the same proportion to the rest. Measure volumes at room temperature: liquids change volume with temperature too, and a liqueur measured straight out of the fridge throws the numbers off.
How low you can go
Below about 25% ABV a homemade liqueur keeps less well, because there is less alcohol protecting it from mold and bacteria. A downward adjustment that crosses that line changes how the liqueur has to be stored. The details are in the guide on how long homemade liqueur lasts.
How do you calculate the ABV when you mix two alcohol bases?
Work out the pure alcohol in each base, add the two together and divide by the total volume. It works for any combination: 95% alcohol with 40% vodka, alcohol with grappa, or alcohol with wine.
For example, a liqueur made with 300 ml (10.1 fl oz) of 95% alcohol and 700 ml (23.7 fl oz) of 13% wine, with no other water. The pure alcohol is 285 ml from the alcohol and 91 ml from the wine, 376 ml in all. The volume is 1000 ml, so the ABV is 376 ÷ 1000 × 100 = 37.6%.
For nocino, mirto or other liqueurs made by steeping fruit or nuts, the calculation gets harder, because the fruit releases some of its own liquid into the infusion, in amounts you cannot measure precisely at home. The practical fix: weigh the fruit or nuts before steeping and again afterwards, once squeezed or pressed, and count the difference in weight as extra water. It remains an estimate.
Why is the result always “about”?
For two reasons. When water and alcohol are mixed the volume shrinks by about 2 to 3%, so the real liqueur is a little stronger than the calculation, by 1 to 3 points. And at home there is no instrument that measures the strength of a sweet liqueur: a hydrometer only works on alcohol and water.
The shrinkage is a physical effect: the ethanol molecules settle into the spaces between the water molecules. A worked example published by the Società Italiana Farmacisti Preparatori, an Italian association of compounding pharmacists, shows it clearly: 64.6 g of 96% alcohol and 35.4 g of water add up on paper to 115.4 ml, while the volume actually measured is about 111.9 ml, 3% less. That is why a freshly made liqueur often tastes stronger than the numbers said.
A hydrometer, the Gay-Lussac alcoholmeter or proof hydrometer, is the floating gauge sold in winemaking kits. It reads the density of the liquid and is calibrated for plain mixtures of alcohol and water. Dissolved sugar raises the density, so the gauge shows a lower figure than the real one: on a homemade liqueur, typically 20 to 35% sugar by weight, the reading is useless. Without a lab, the calculation remains the reliable method.
The formulas at a glance
Every calculation starts from the same principle: count the pure alcohol and compare it with the volume of the liqueur. The formulas below cover the amounts for a chosen strength, the ABV of a liqueur, a mix of two bases and the two adjustments of a finished liqueur.
| What you want to know | How to work it out |
|---|---|
| Pure alcohol | milliliters of alcohol × strength ÷ 100 |
| Volume of the dissolved sugar | grams of sugar ÷ 1.6 |
| Water to reach a chosen strength | (pure alcohol ÷ target ABV × 100) − alcohol − sugar volume |
| ABV of the liqueur | pure alcohol ÷ total volume × 100 |
| ABV of a mix of bases | pure alcohol of every base added up ÷ total volume × 100 |
| How much to add to a liqueur that is too strong | (pure alcohol ÷ target ABV × 100) − current volume |
| How much alcohol to add to a liqueur that is too weak | volume × (target ABV − current ABV) ÷ (alcohol strength − target ABV) |
The result is an estimate, realistically within 1 to 3 points of a lab measurement.
Frequently asked questions
Can I use a hydrometer if my liqueur has very little sugar? A hydrometer can give a rough idea on nearly dry liqueurs, but even a few tens of grams of sugar per liter make the error significant: it is better to rely on the calculation.
Does the calculation work for nocino and mirto, where no water is added directly? Only in part: fruit and nuts release their own liquid, which adds to the final volume in an amount that is hard to measure at home without weighing the ingredients before and after steeping. Take the resulting ABV as an estimate.
How accurate is the home calculation overall? Allowing for the specific gravity of sugar and the shrinkage in volume, it is typically within 1 to 3 percentage points of the real value measured in a lab.
Do I need to redo the calculation if I change brands of alcohol? No, as long as the strength on the label stays the same, 95% or 96%: the producer changes, the number in the formula does not.
Does the calculation change if I use honey instead of sugar? Yes: honey has a different specific gravity, about 1.4, so it takes up more volume than granulated sugar for the same weight, and you need to recalculate with its own specific gravity.
Is it better to lower the ABV with water or with syrup? It depends on the sweetness. Water lowers both the strength and the sugar per liter; a syrup with the same concentration as the liqueur lowers only the strength.
Legal note: in the United States, infusing legally purchased alcohol for your own use is allowed; selling it requires licenses, and distilling at home requires a federal permit. The strengths given in this guide are calculated estimates. 95% alcohol is flammable: keep it away from flames and lit burners while you pour it or add it to a liqueur. Please drink responsibly. This content is for readers 21 and over.
Techniques and recipes in a few slides, on Instagram: @liquori.it