Why chocolate overheats, and why it cannot be fixed

Past roughly 50°C for dark and 45°C for milk and white, the sugar begins to caramelise and any milk solids begin to scorch. Both reactions change the molecules involved, which is why the damage is permanent in a way that seizing is not.

The result is thick, dull, slightly grainy, and smells cooked. It will not temper, will not coat properly, and tastes of burnt sugar.

Chocolate holds its moulded shape when melted, so a bowl can be entirely liquid underneath while looking untouched. A cook judging by appearance keeps heating, and the base of the bowl runs far above the average temperature.

Short bursts with stirring between each solve it entirely, because stirring both reveals the true state and evens out the hot spots.

White chocolate scorches at temperatures dark chocolate tolerates comfortably, because it is mostly sugar and milk solids with no cocoa solids to buffer them. It turns yellow and clumpy rather than merely thick.

Half power in a microwave, or a bain-marie taken off the heat entirely and left to melt in residual warmth, is the reliable approach.

Nothing recovers it as chocolate. If the burnt note is mild, it can go into something strongly flavoured — a spiced brownie, a chilli hot chocolate — where the cooked character is not the dominant flavour.

If it is pronounced, the honest answer is to discard it. Using badly scorched chocolate in a bake produces a bake that tastes scorched.