In a food processor, combine the bacon, mustard seeds, caraway seeds, vegetable oil and ground ginger and process to a paste. Set the pork loin roasts on a large rimmed baking sheet. Spread the bacon paste over the meaty side of the roasts and refrigerate overnight.
Preheat the oven to 400°. Bring the roasts to room temperature and season all over with salt and pepper. Set the pork in a roasting pan, fat side up. Roast in the upper third of the oven for about 1 hour and 15 minutes, until an instant-read thermometer inserted in the thickest part of the roasts registers 150°. Transfer the roasts to a carving board and let rest for 10 minutes. Carve the roasts and serve.