W [Flour]

W Also known as, “the deformation energy”, the W represents the force required to inflate the dough bubble until rupture.  Literally the W is the area under the curve on the graph, multiplied by a factor of 6.54.  This value generally indicates the overall baking strength of the sample.  The water absorption is generally thought to increase as the W increases.  Loaf volume is also thought to increase as the W value rises.  

Bread flour W values tend to be 200+, with number up to 400 being especially appropriate for dough undergoing long fermentation times.

Water activity [AW]

Water activity is defined as the ratio of the water vapor pressure of the food to that of pure water