I started off a small batch of Limoncello this morning, I used the zest of 5 middle size lemons, and 640 mls of alcohol at 75.5% (151 proof)  I am fortunate to have a small amount of grape neutral spirit at 96.5% alcohol, left from the days when I was working from home, and this accidently went in my cupboard and not taken back in to work This was diluted it with some water to get the 75.5% alcohol level, and I steeped the lemon zest in it. I will check it in 3 weeks, when apparently the zest should be white and brittle by then and all the colour and flavour will have been extracted. If it has reached this stage, then it just needs filtering and diluting with a simple sugar syrup of one and a half cups of water and one cup of sugar (a cup is 240 mls in volume) and leaving a further week whilst the flavours marry. The best advice is to then keep the bottle in the freezer until needed. This will slow down the oxidation process and prevent a piney note developing as it gets older if stored ambiently.