The difficulty associated with this method of extraction revolves around three main factors: selectivity, power consumption and yield. The first issue is that the set up for alcohol extraction varies much more drastically than with scCO2, for instance the same alcohol may not be used, or the method of compression is different or is not even preset in lower end systems. These variance means that very different operating conditions will be necessary for each and that the yield despite the compensation of other factors, such as input particle size, will not be uniform, with some systems being superior. Provided a superior system is being used finding the balance between the, previously mentioned, three factors is extremely difficult.
The main issue that dictates the balance is the operating temperature. The goal is finding the optimal temperature that gives sufficient yield, while maintaining high enough selectivity to simplify the removal of high melting point lipids, with the added dimension of minimizing the energy consumption. The energy consumption has the complicated relationship with the other two factors. The higher the selectivity, the lower the operating temperature and the higher the energy demand; however, the higher the yield the more significant the energy consumption for the separation step. This is not even factoring in the effect of operating temperature on the amperage required for compression, which is affected by viscosity of the batch. It also does not account for higher operating volumes associated with lower selectivity.Through proper consideration it is possible, and necessary, for the identification of a point between room and supercooled operating temperatures that will maximize production, while maintaining premium quality and at the best price point.