Very good primer on bread terms and ingredients

Why do my homemade un-enriched sourdoughs tend to change colour less when toasted unlike bought bread, which has many additives in it, which seem to toast much better?

When reading through your link I found out why when I got to adding milk into the bread. Lactose isn't digested by the yeasts or bacteria and therefore the sugars aren't used up during fermentation unlike my un-enriched sourdoughs. So there are more sugars left, in the bread, which makes it toast better and turn brown.

I suppose by reason of logic if you take your sourdough more to the outer limit of fermentation time so more sugars are used up then it'll brown less when toasted. And if you don't go for a very long fermentation, playing safe, there will be sugars left for a better toasting.

Thank you.