My Italian host family used to talk about making Limoncello. They insisted one had to use lemons from Sicily. I used Lemons from the natural foods co-op. They're probably not from Sicily, but they're organic. I gave them a good scrub anyway.
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All that soaking produces flecks of schmutz, so I used coffee filters and a small funnel to filter the lemon vodka. By the way, I can't wait to experiment with other infused vodkas.
I used organic sugar for the sugar solution, which isn't totally white. The result is a duller, cloudier Limoncello, but still delicious.