Add the bread flour, all purpose flour, salt, dry yeast, ripe sourdough starter, olive oil, and water to a stand mixer bowl with the bread dough attachment hook or a large mixing bowl. With the mixer on the first speed, mix the ingredients until it forms a sticky dough that pulls away from the sides of the bowl. You may need to add up to 1/4 cup water (with the mixer turned on) if the dough is dry and isn't too sticky. This is common in the winter as flour tends to absorb more liquid when it's cold outside, making the dough drier. If mixing by hand, mix all the ingredients with a wooden spoon until they start to come together, then place on a work surface (no need to flour), and knead until the dough comes together in a sticky ball. Add a touch of extra water and knead until combined if the dough is dry. Use a bench scraper to scrape up the excess dough and knead it back into the ball of dough.