A lean bread is flour, water, salt and yeast. An enriched dough adds fat, eggs, milk and sugar. They make a softer, richer, longer-keeping bread, and each one changes how the dough behaves.
| Ingredient | What it does to the bread | What it does to the dough |
|---|---|---|
| Butter | A soft, tender crumb and a rich flavour | Coats the gluten and weakens it; slows the rise |
| Eggs | Colour, flavour and a light, springy crumb | Add moisture and strength, but make the dough sticky |
| Sugar | Sweetness, a golden crust, longer keeping | Draws water away from the yeast and slows it down |
| Milk | A soft crumb and a browner crust | Brings fat and sugar of its own |
Why everything is slower
Sugar and fat both slow yeast down. Sugar pulls water away from the yeast cells; butter coats the flour and gets in the way of the gluten. That’s why enriched doughs use more yeast than lean bread and rise for longer, and why the butter goes in only after the gluten has had a chance to form.
Why the dough is sticky
An enriched dough feels wetter and stickier than a bread dough with the same amount of liquid. The answer isn’t more flour, which makes a dry, heavy bake. It’s patience: knead until the gluten develops and the dough comes away from the bowl on its own.
Why we chill it
Butter is soft at room temperature and firm in the fridge. Chilling a brioche or babka dough overnight sets the butter, so a soft, greasy dough becomes firm enough to shape neatly. It also gives the flavour time to develop.