Wash the lemons well, then peel into long strips—use a light touch, you want to leave as much of the pith behind as possible. If using Everclear 190/189, 10 lemons will be enough; for the other alcohols, you’ll need to peel more lemons as the proof level decreases.

Using a sharp knife, scrape away the remaining white pith on the inside of the peels. Too much pith makes for a bitter end result.

When the infusion is ready, heat the water in a large saucepan over high heat. Add in the sugar, whisk, and bring to a boil. Boil until the sugar is completely dissolved, about two minutes. Let simple syrup cool to room temperature.

Pour the simple syrup into the lemon infusion. Close the lid on the jar again, and shake well to combine.