Tall oil, also called "liquid rosin" or tallol, is a viscous yellow-black odorous liquid obtained as a by-product of the Kraft process of wood pulpmanufacture when pulping mainly coniferous trees.[1][2] The name originated as an anglicization of the Swedish "tallolja" ("pine oil").[3] Tall oil is the third largest chemical by-product in a Kraft mill after lignin and hemicellulose; the yield of crude tall oil from the process is in the range of 30 – 50 kg / ton pulp.[4] It may contribute to 1.0 - 1.5% of the mill's revenue if not used internally