French Style Potato Sourdough

I decided to use some of my leftover mashed potatoes along with some of French Style flour from KAF I bought during my recent visit. I milled some fresh whole wheat flour and instead of using it as is I decided to try sifting out some of the hard bits and ended up with a medium extraction flour. I have a finer sieve which next time I will use as a second step to get a real high extraction flour.