3.3 Properties of the extracted coffee oil
The results of oil characterization are shown in Table 2. The iodine value is very low, meaning that the
coffee oil is very saturated (its molecules have few double bonds). The viscosity of the oil is too high to
be used in direct combustion engines. The oil is also too acid to be directly converted into biodiesel
without any pre-treatment, which may indicate a higher degree of oxidation and occurrence of
hydrolysis reactions (Knothe, 2007). The relatively high HHV suggests that this oil can be used for
direct combustion.