I beg for forgivness, what I have calling Pancakes is what you call crepes!!!
But the Ungspannkaka and Fläskpannkaka ate quite thick, so a batter for crepes but poured in a much, much thicker layer. Maybe 2-4 cm thick.
My mum (and her children incl myself) use yeast in the batter for the pancakes ( your pancakes )
Crepes - nothing to fluff it up.
She tought us to put about a quarter of the normal amount, and leave a day. I would think you get some sort of sourdough taste?
The rye bread let to raise a day gets an acidic flavour.
In yhe batter for a kolbulle , you just mix flour and water. Maybe some sourdough fermentation, but not much, remember, in the northern half of Sweden it is quite cold even during summer!