Core Mechanism
Cream can separate under excessive or uneven heat, leaving a grainy fat-and-liquid appearance.
Conditions and Controls
Gratin Dauphinois uses a 170 C oven without fan, loose foil during the first bake, and gentle optional warming of 35% cream before assembly.
Culinary Implications
A stable cream phase helps the potato gratin bake evenly and remain cohesive; if it splits, lower or even out the heat.