I started a sour dough mix, about two years ago. Then I carried it across the country, in our camper, and sat it out so it would get yeast from all over the country. We are very happy the results, but I have a question about bread flour.
I was using "King Arthur," but when the shut down happened I wasn't able to get it. I found a fifty pound bag of "Sir Lancelot," on the internet. They are made by the same company, the difference is that King Arthur is 12% protein while the Sir Lancelot was 14% (standard all purpose flour is 9% protein.)
I read that some expert that spent a lot of time testing, found "Gold Medal" bread flour superior to the King Arthur.