This homemade limoncello boasts rich lemon flavor without being too boozy or sweet. Look for unwaxed organic lemons, or be sure to give the whole citrus a good scrub before peeling. Juice leftover peeled lemons, and freeze juice up to 3 months.
Using a vegetable peeler, remove peels from lemons, being sure to avoid any white pith, to yield 10 1/2 ounces lemon peels. Place peels in a 3-quart jar with a hinged lid. Reserve remaining lemons for another use. Pour alcohol over peels, making sure peels are submerged. Fasten lid on jar, and let stand in a cool, dark place 24 hours.
Line a wire-mesh strainer with cheesecloth, and pour lemon mixture through strainer into a large pitcher. Discard solids. Repeat straining 1 time.
Stir together 51/2 cups water and sugar in a large saucepan over medium; simmer until sugar dissolves, about 5 minutes. Add to infused alcohol, and stir to combine. Pour into sealable sterilized bottles, and cover tightly. Store at room temperature. Chill before serving.
Limoncello can be made up to 1 year in advance.