IMO, that "1393" recipe needs to be viewed through 21st Century eyes. The appearance of "black smoke" suggests that the mead maker was planning on all but carbonizing (AKA burning) the honey. The more carbonized the honey the more bitter it will be - bitter in an unpleasant way. What you want is to caramelize the sugars, not burn them and that means you do not need to wait for signs of burning before you remove the honey from the heat. One way to determine how much caramelization you want/have is to very carefully use a a chopstick or something similar to collect a drop every 15 minutes or so and allow the drop to fall on a white dish or plate. You can then remove the honey from the heat when the drop, hardening like toffee on the plate, reaches the color you are seeking. The longer it cooks the darker the color. But there is no requirement that a bochet needs to have all the sugar in the honey caramelized. You, not the stove oven, crockpot or fire pit, are in control.