Methods of increasing the yield of tall oil soap from a black liquor are provided. In an embodiment, the method comprises adding a separation aid to the black liquor. The separation aid comprises alkyl alcohol alkoxylates of formula RO[(CH.sub.2CHCH.sub.3O).sub.x(CH.sub.2CH.sub.2O).sub.y]M and combinations thereof, wherein R is straight or branched alkyl of about 8 to about 22 carbon atoms; x is 1 to about 20; y is about 20 to about 80 and M is H or an alkali metal.