Trim any excess meat or skin from the raw fat. Cut the fat into chunks.
Place the fat pieces in a freezer-safe container or bag and freeze overnight. Freezing firms up the fat, making it easier to grind and helping it render more evenly and efficiently.
Grind the frozen fat using a meat grinder or food processor. Grinding the fat helps increase surface area, speeding up the rendering process. You can also chop it with a knife into small pieces.
Transfer a small amount of the frozen fat to a large, heavy-bottomed pot or Dutch oven. Place it over low heat to medium heat. As the chunks of fat melt, begin adding more fat to the rendered fat. We have found that adding too much fat to the dutch oven actually hinders more than helps.
Allow the fat to slowly melt, stirring occasionally to prevent sticking or burning. Be patient, as this process can take several hours.
Keep an eye on the temperature of the fat. Ideally, you want to maintain a temperature between 225°F to 250°F (107°C to 121°C) to gently melt liquid fat without burning it.
As the fat renders, you may notice foam or impurities rising to the surface. Use a spoon or ladle to skim off these impurities and discard them.
Once the fat has completely melted to a liquid state and there are no more impurities rising to the surface, it's time to strain the lard. Line a fine mesh sieve or cheesecloth over a heatproof container and carefully pour the liquid lard through it to remove any remaining solids. There will be many small pieces that do not fully render.
Allow the strained lard to cool to room temperature before transferring it to a clean, dry jar or container. Store the lard in the refrigerator or freezer for long-term storage.