Sharp and brassy, lemon ice can be a bitter experience, but it doesn't have to be that way.
If your tap water has ''off " flavors, filter it, if possible, before use in this recipe. Better still, use bottled water; tasters preferred lemon ice made with spring or mineral water. The addition of vodka yields the best texture, but it can be omitted if desired. Because freezers differ in temperature, a wide range of freezing times is given in the recipe. Lemon ice does not keep well; it's best served within an hour of being ready. If making it in advance is crucial, try the food processor method; the ice cubes can be frozen for up to 5 days and can be processed--which takes no more than a couple of minutes--whenever you're ready. Leftovers, if you have any, can be brought back to life by breaking the mass into large chunks and pulsing the chunks in a food processor.
Adapted from America's Test Kitchen. Prep time includes chill/freeze time. Cook time is freeze time.