Peel the root vegetables and cut into chunks. Clean the leek and cut in half. Rinse the bones, dry and brush with vegetable oil and place them on a GN container and put in the Retigo combi oven for about 7 minutes on 220°C on hot air. Place the bones, ribs, all the vegetables, herbs, spices and water into the deep 200mm GN container or you can use a big pot that you are able to fit into the Retigo combi oven. Set hot air, 110°C for 12 hours. Do not cover the GN container.