1 fifth (750 ml) bottle of grain alcohol
1 1/2 fifths water (about 4 1/2 cups)
1 1/3 cups sugar
Grate the zest from the lemons using a microplane grater or a zester with small holes, making sure to get only the yellow skin and none of the white pith (this can impart a bitter flavor). Place the zest and grain alcohol together in a glass jar, seal with a lid, and let sit for about three weeks. Shake occasionally. At the end of this time, the alcohol will have drawn out most of the lemon color from the shreds of peel. Pour through a strainer, pressing down to release any remaining oils, and then discard the peels.
Dissolve the sugar and water together in a pot. Mix this syrup in with your strained alcohol. Filter the combined mixture through several layers of cheesecloth, or, preferably, a coffee filter to remove any remaining impurities. Letting it sit for a month or so before sipping allows the flavors to mellow and develop, although I'm seldom that patient. Chill thoroughly in the freezer before enjoying.