Over-kneading brioche dough results in a tough, dense bread due to excessive gluten development, which makes the dough difficult to shape and reduces its characteristic tenderness.
Brioche is a rich dough, high in butter and eggs. These ingredients naturally inhibit gluten development, which is what gives bread its structure. Kneading develops the gluten strands, creating elasticity and strength. However, over-kneading pushes this process too far. In brioche, excessive gluten development leads to several problems:
Tough Texture: Overdeveloped gluten creates a tight, rubbery network, resulting in a bread that is dense and difficult to chew.
Difficulty Shaping: The dough becomes overly elastic and resistant to shaping. It will constantly spring back, making it hard to achieve the desired form.
Reduced Tenderness: The delicate, melt-in-your-mouth quality of brioche is lost as the gluten structure becomes too strong, overpowering the richness of the butter and eggs.
Dryness: Over-kneading can also lead to a drier final product, as the tight gluten network prevents moisture from being evenly distributed throughout the dough.
The key to perfect brioche is to knead it just enough to develop a smooth, elastic dough that still retains some softness. It should be strong enough to hold its shape but not so strong that it becomes tough.
Use the windowpane test to check if your brioche dough is kneaded enough. Gently stretch a small piece of dough between your fingers. If you can stretch it thin enough to see light through it without tearing, the gluten is sufficiently developed. If it tears easily, continue kneading for a few more minutes and test again.