Rule of 320?
On the Sourdough Home website it states:
The last wrinkle is that when you are using sourdough or other preferments the rule of 240 becomes the rule of 320. Take the temperature of the sourdough or other preferment as well as the temperature of the flour, water and room. Subract all from 320, rather than 240. If you are using Celsius, this becomes the rule of 100.




