Before the 1700's, Malting Barley was a hand-crafted, boutique process that produced inconsistent results. With the introduction of coke-fired kilns, Maltsters improved their control of the process to the point that light-colored or 'Pale' malts were now possible. These new products caught on in a big way, spawning new styles of beer including Porter, Mild, and Pale Ale. In England, the Pale Ale style was divided into several sub-styles including Extra Special Bitter, a classification typically reserved for Pale Ales brewed at over 4.8% ABV.