You should start glazing a ham when there is about an hour or less of cooking time left. Applying the glaze too early can cause it to burn instead of caramelizing properly. Typically, you take the ham out of the oven with about an hour left, brush it all over with some of the glaze (about one-fifth of the total glaze), and then return it to the oven. Every 15 minutes, take the ham out again and brush on more glaze. When the ham reaches an internal temperature of 145°F, take it out and brush the remaining glaze on, then let the ham rest before serving. This method allows the glaze to form a delicious, shiny caramelized crust on the ham.

Other recipes suggest starting to glaze around the last 20 to 30 minutes, applying the glaze multiple times to build up a sticky, flavorful coating.

In summary, the glaze process happens near the end of cooking—usually in the final 30 to 60 minutes—with repeated glazing every 10 to 15 minutes for best results.