Grind wheat berries. 1 cup of wheat berries yields about 1 and 1/4 to 1 and 1/2 cups of fresh milled flour.
Mix olive oil, sourdough starter, water, and salt in a bowl. Add fresh milled flour and mix until well incorporated (3-5 minutes until dough becomes smooth)
Shape the dough into a ball in the mixing bowl and cover with a damp towel or wrap in plastic wrap for at least 30 minutes. This keeps the dough moist and prevents the "skin" from forming over the top of the dough. You can long-ferment the dough for 12-24 hours at room temperature. **Note- fresh milled flour ferments more quickly than store bought flour, so a shorter ferment might be needed depending on kitchen temperature**
Preheat a well-seasoned cast iron pan. You want the pan to be uniformly hot, and then adjust the temperature down to medium before you add the first tortilla.
Divide the dough into equal pieces, or simply mold dough into roughly 2 inch balls as you go.
On a floured surface or on parchment paper, use a rolling pin to roll out a ball of dough as thin as you can without making holes in the dough. If the dough does not remain flat when rolling, rest the dough for another 10 minutes before trying again.
Carefully lift tortilla and lay flat in the cast iron pan, frying for 30-60 seconds on each side.
Place cooked tortillas on a plate under a towel to trap moisture, keeping them soft while you cook remaining tortillas.
Store at room temperature or in the fridge for 2-3 days or freeze for 2-3 months.