There are many limoncello recipes on the web, but so many are careless or incomplete that I add ours to the cacophony. Key points: You have to use the right kind of alcohol, you have to taste every day while you steep zest in alcohol, and the leftovers make lovely marmalade. Ingredients:
- Alcohol (60-96%, not 40%)
- Sugar (either white or light brown)
For 1l of 96% alcohol, you should have 1-1.5kg of sugar, 2kg of lemons, and the amount of pectin depends on the lemons and your endurance. The amounts below assume 1l of 96% alcohol.
The reason that you can't start with 40% alcohol is that the end result has to contain about 32% alcohol in order to remain entirely fluid in the freezer, and the alcohol is mixed with a syrup. If the syrup is to reduce the alcohol content by only 8%, you would have to make it with just a few tablespoons of water, and you simply cannot dissolve enough sugar in that little water.
The lemons need to be organic. Limoncello uses the outermost half millimeter of the lemons, which is precisely where the wax and/or insecticide is on conventionally grown lemons. A bit of wax or insecticide won't kill you, but they won't taste good either.
Peel the lemons with a sharp knife, making sure to get the zest only (the yellow layer). The white layer is called pith and will spoil the taste if you have too much of it in the alcohol. Chopping the zest at this point helps with the marmalade, but it doesn't matter for the limoncello. Put the zest in alcohol and steep it for a few days in a dark place. Store the rest of the lemons in the fridge to make marmalade.
The alcohol should be strong. A higher percentage (up to 96%) makes it easier to adjust the taste at the end, a lower percentage makes it easier to taste the mixture while it's steeping. The alcohol dries the zest, so higher percentage makes it more crunchy too. If you use 96% you have to chop the zest very finely.
Taste it once every night. The taste will change on the first and second days, then it doesn't change very much for a few days, after about a week it changes again (well, at least that's my experience) and the lemon taste becomes stronger and somehow different, and it's time to proceed.
Mix 1l water and 400g sugar, heat it just enough to dissolve the sugar, then leave it to cool.
Boil a pot of water and boil glasses for the marmalade. Leave them upside down on a clean cloth; when you need them you'll too busy stirring marmalade to do this.
Check that the lemons are still good, and discard any that lost in the storage lottery. You may want to add an orange or bergamot, or several. Juice the lemons and divide the juice into three containers, two of them just 1dl and the third containing the rest.
Strain the alcohol from the limoncello and put the chopped zest into the largest juice container. If you didn't chop the zest before, do it now, and worry about the aromatics you're leaving on the cutting board. It's better to leave a little alcohol in the juice than to let the zest dry.
Mix the strained alcohol into the cool syrup (if it's still a little warm, a tiny bit of alcohol will dissipate). Taste and add more water or syrup: What you now have contains 45% alcohol, much too strong, so you will have to add water, syrup or both, up to 8dl. You have to find the right spot by taste, it depends on the lemons.
If you add about 5dl water/syrup in the final step, your limoncello contains 35-40% alcohol, which is fine. If you add more than about 8dl there may be tiny specks of ice in the limoncello.
Bottle and put into the freezer. Turn to the marmalade while the limoncello is freezing. This following rough recipe is based on an article on citrus by Phil Iddison in Petits propos culinaires, and produces good results for every kind of citrus we've tried. The author doesn't add external pectin, and I'm sure his marmalade is better.
Chop the lemons coarsely, then boil them (ie. the flesh, membranes, stones and pith, but not the zest or juice) with a little water and push as much as possible through a sieve. Add 1dl of water and repeat the boil/sieve cycle, and repeat, and repeat. The mush you get through a sieve is rich in pectin and aromatics, and is the base of the marmalade. This is wearisome and takes hours. You should get perhaps 1.5l of base if you started with 2kg of lemons. 1l can be a strain with some lemons, >1.5l doable with others. At the end, most of the mass will be reduced to a little pulp and the stones will have more or less dissolved. If this is too tiring, stop earlier and compensate with pectin.
Discard the chopped lemons from the first pot. Dissolve 100g of sugar and 35g of pectin in one of the 1dl juice containers, then add that to the base and start boiling. Stir often. Add more sugar until you guess that the mixture of the base, the zest and the juice will taste as you want; we usually have about 750g in total at this point but many people like more. Add the rest of the juice to the base and bring to the boil again (you want to boil the juice and zest, but as briefly as possible). Keep stirring. You'll see a sort of bubbly viscous mass. If you don't, if it's fluid rather than viscous, you lack pectin and you should have sieved harder and/or must add more pectin now. You can dissolve more pectin in the final 1dl of juice before you mix that in, if you need to. Boil another minute, still stirring, then fill the marmalade into glasses before the alcohol from the zest evaporates completely.
Meanwhile the limoncello will have become cold enough to taste.