While you can use any type of lemon you like, Meyer lemons will make a slightly darker (though more fragrant) limoncello. Smooth, thick skins are the best for zesting. Any white pith can turn your liqueur bitter, so the zest is the only part of the lemon skin used in this recipe. A microplane zester is the easiest tool for the job.

You can substitute 100- or 80-proof vodka for the high-proof neutral grain spirit. Using a spirit that is more than 151 proof will make for a harsh end result. Vodka will impart a little flavor of its own to the limoncello, so I've read that many people use a water filter pitcher (like Brita or Pur) to "purify" the vodka first. (The vodka "flavor" doesn't bother me, so I've never tried this myself.)

Two weeks is the recommended steeping time, but as little as one week will work. Longer steeping times lead to a more mellow flavor, so feel free to let it steep for up to three months.

Filtering isn't just for appearance. Small particles can change the limoncello's flavor over time and may freeze if you choose to store your liqueur in the freezer.