I'm reading the book "Bread Alone" by Daniel Leader.The problem is on the page 58, temperature of flour,temperature of your kitchen and friction factor. What is factor?? If I mix the dough one minute that the dough will rise 1F and if I will mix it let's say 20 minutes that the dough will rise 20F??? He is saying that his friction factor number is 14. He is saying 60 F flour temperature, 80 F kitchen temperature and 14 F friction factor total is 154 F then 240 F ideal total minus 154 F real total is 86 F temperature to make the water. How he found the friction number with out the mix water and flour first??