Tall oil rosin is a thick yellow-black odorous liquid, which is obtained as a by-product during the kraft process of wood pulp production and while pulping trees, mainly coniferous ones. Tall oil rosin is a combination of resin acids such as abietic, palustric, ihydroabietic, isopimaric, and neoabietic. It contains up to 6% of unsaponifiable matters and is the third largest chemical by-product yielded in kraft mills after lignin and hemicellulose.