s this method is suited to tall oils which may be manufactured by distillation such that removing the c16 fraction may involve a modification of existing distillation conditions fractional distillation may also be used for the ester product itself the third method involves the choice of alcohol used to esterify the fatty acids and rosin acids in the case of tall oils according to the method of the invention multi functional polyols glycols iso butanol and tert butanol can each produce bio jet esters with exceptionally low freeze points as well as higher energy contents than methyl ethyl and propyl esters the fourth method of the invention involves esterification of a caprylic c8 and or caproic c6 acid concentrate in one embodiment obtaining the concentrate begins with hydrolysis of whole palm palm kernel or coconut oil the free fatty acids that result are then fractionated by distillation to yield a distillate rich in caprylic and caproic acid as can be seen from table 2 adapted from graboski m s et al u201c combustion of fat and vegetable oil derived fuels in diesel engines u201d prog energy combust sci vol 24 pp 125 164 1998 the esters of caprylic and caproic acid have excellent freeze points these esters.