Be sure to read the post before you begin this recipe. It contains more details on the equipment that you need for this slow food project.
Keep the slabs of fatback at 38-40°F/3.3-4.4°C (almost frozen) for easier cutting and grinding. Cut the fatback into 1-inch (2.54 cm) cubes (or smaller). I chose to keep the skin on the fatback.
Using a meat grinder, coarsely grind the cold fatback cubes. Send them through the grinder slowly, being careful not to jam your grinder. (If your grinder cannot handle the fat cubes or you do not have a grinder, you may skip this step. However, it is likely that your lard yield will be lower.)
Put the ground fatback (or the fatback cubes) in a slow cooker and set it on low. Cover the slow cooker.
Every hour, siphon off all of the oil you can into food-safe jars. I used a turkey baster to make this easier. Leave the solids in the slow cooker.
Continue collecting the lard every hour (or every half hour, if desired) for a total of 2-3 hours. The lard you collect should be clear and nearly colorless. I found that the oil collected beyond three hours had turned golden and was overcooked.
Let your lard cool to room temperature. Put lids on the jars and store them in the fridge or freezer, depending on how quickly they will be used. Keep in mind that homemade lard does not last as long as store-bought lard in the refrigerator.