When baking bread that calls for enriched dough (additions like eggs, milk, sugar), sourdough leavening (as opposed to commercial / instant yeast) can often result in a lack of desired crust browning (AKA “the Maillard reaction”) leaving you with a pale bread that looks bland and underbaked. In this post we go over reasons for this and provide a solution in the form of a sweet, stiff levain that gives results much closer to yeast alone.

https://breadtopia.com/sourdough-starter-and-maillard-reaction-in-enriched-doughs/