Beef bones

Beef bones sold for stock, with meat and connective tissue still on them. German shops sell them as Fleischknochen. Most of the gelatin comes from the connective tissue on the bones, not from the bone itself. Pick packs with the most meat and tissue on them. Roast them before a brown stock. A roast at 200 degrees C fan for 40 min browns the surface by the Maillard reaction and gives the stock its colour. Veal knuckles give more gelatin. When there are none, these are the next best choice.