The venerable Limoncello Spritz originated in Italy along the Amalfi coast using sfusato lemons. The region is so proud of their lemons, their variety is protected by IGP/PGI (Protected Geographic Indication). Think of IGP much like the DOCG designation in your favorite Italian wine. The variety of lemon is larger than your garden variety you pick up at the supermarket, and is much sweeter with a less bitter pith. It makes for amazing limoncello and goes well in the spritz!