According to her research and experiments, the shorter fermentation times used in nearly all sourdough available in the US are not long enough to fully "convert" the gluten. Her longer version is supposed to dramatically reduce the allergenic potential and also reduce the breads glycemic impact. A lot of commercially sold sourdough is actually only allowed to ferment a very few hours and often, vinegar or some other acid is added to make it taste more sour. Of course that way you do not get anywhere near the complexity of flavors nor more importantly, the fermentation products which create them. I do know her bread is unlike any other I have had and tastes quite wonderful.
Below is her basic recipe. Use whatever flour(s) and hydration levels you prefer for the bread itself. Starter is used at 100% hydration which means equal weight of flour and water.
Long Rise Sourdough
Mix flour and water only and let autolyse for 12 hours
Mix approximately 50% of the total flour flour with equal weight of water plus starter culture
Knead about 5 minutes to develop the gluten
Cover well and let ferment for 15 hours
Add rest of flour and water (which can be premixed and allowed to "autolyse" during the 1st fermentation for the other 1/2)
After the 15 hours, knead the two together and proof until nearly doubled in size
Bake 450 degrees covered X 30 minutes then 15 minutes uncovered.
Or
Slow bake at 300-350F for longer time. I have been baking at 250F for 2 1/2 hours.