Try to find lemons with a rough looking skin, the smooth ones don't produce as much zest. Also, if you can't find organic lemons, make sure to scrub them under warm water to remove any wax coating.
Use a Microplane zester/grater to zest the lemons. It makes a fine zest, and really goes through the lemons quickly.
Get a mid grade vodka. It's a waste of money and good vodka to use Grey Goose or Stoil’s! That being said, don't go cheap either, you will end up with a rough tasting liqueur. Smirnoff 100 proof is about the perfect match for this recipe.
Only use glass containers to ensure no funky taste from plastic, or whatever was previously stored in the plastic!
Zest lemons and place in a glass container. Pour Vodka over zest, making sure to completely cover.
Seal container tightly and let mixture age for 2 weeks.
After 2 weeks, strain vodka into another glass container and discard zest.
Make a simple syrup by heating 4 cups of water in a saucepan, and stirring in the 4 cups sugar until dissolved. After syrup is completely cooled, stir into vodka. Let age for another 2 weeks.
After the final two weeks, bottle Limoncello and store in the freezer. Serve cold, straight from the freezer!