Preheat your oven to 325°F (165°C).
Lay the pork belly skin-side down on a clean surface. If the pork belly is rolled, unroll it.
In a small bowl, mix together the olive oil, garlic, rosemary, sage, fennel seeds, salt, black pepper, and lemon zest.
Rub this mixture all over the pork belly, making sure to get the seasoning into any crevices.
Roll the pork belly tightly and secure it with kitchen twine at regular intervals to hold its shape.
Place the rolled pork belly seam-side down on a rack in a roasting pan.
Pour the white wine into the bottom of the roasting pan.
Roast the porchetta in the preheated oven for about 2 1/2 to 3 hours, or until the internal temperature reaches 165°F (74°C) and the skin is crispy and golden brown.
If the skin is not as crispy as you like, you can increase the oven temperature to 450°F (230°C) and roast for an additional 10-15 minutes, or until the skin is crispy.
Remove the porchetta from the oven and let it rest for 20-30 minutes before slicing.
Slice the porchetta into thick pieces and serve with rosemary sprigs and lemon wedges, if desired.
Enjoy your meal!