One aspect of this invention relates to a method and digester for reducing the deposition of calcium-based scale in a wood chip digester including extraction from the digester of first and second quantities of cooking liquor having respective first and second calcium concentrations, treating the extracted cooking liquors to produce a cooking liquor having a calcium concentration less that the calcium concentration of the either of the first and second extracted cooking liquors, and, reintroducing the treated cooking liquor to the digester. Another aspect of this invention relates to a method and digester in which through put through the digester is increased by the continuous addition of process liquor into the digester preferably at an upper region of the digester.