PB is close ,it is not how clean or dirty it's other factors.

And it was always thought that it was the water only .

It has been proven not to be only the water ,and the guys that proved it are making a small fortune.

It is not just the bagels and dinner rolls.
The real money comes from there sub bread and there are hundreds if not thousands of places getting the bread now..

And yes to all the people that think they know,that do not ,there is a science to baking the bread away from the area...

It is very difficult, hence why most get the recipe, and know how , from the same guy..(And often it still does not work)