The popular oil extraction methods.
The solvent extraction. The oil-rich commodity is bath with hexane, the likes of petroleum ether. It dissolves the commodity oil content. The oil is then purified by boiling the hexane off.
Hexane has low boiling temperature, about 36 to 50°C. Boiling to such temperature range will drive the hexane off and leave the oil behind. The solvent is collected in another chamber and use for repeated extraction.
This method is high yielding and preferred by big commercial processors.
Screw press. Can either be slow speed and temperature regulated or equipped with cooling mechanism to protect sensitive oils. A low yielding method meant for production of higher quality and healthier oil. Or, high speed and heated process. High speed screw press rotation tend to produce heat which aids extraction. If the heat produced is not enough, external heat source is applied.
Press and ferment. As far as my knowledge is concern, this method is only applicable to virgin coconut oil. Grated coconut is pressed to expel out mixture of oil, water and other substances. Then naturally fermented overnight to let oil separate on top.
..press and boil. Instead of boiling, the extracted liquid is boiled to allow evaporation of unnecessary portion. The method yield more but lower quality oil.
The cocoa butter extraction process. Extracted by batch press. Roasted nibs are subjected to milling producing fine textured liquor. Then butter is extracted via batch press while still in liquid state.
Can cocoa butter be extracted by solvent extraction? I think it can be! Repeatedly bath the roasted nibs in hexane. Then heat the solution to hexane boiling temperature to get purified cocoa butter.
It is possible but likely to have detrimental effects on flavor and safety. Roasting process develops cocoa flavor. Why take a risk by adding harmful and odor offensive hexane? It can be removed by heating but we never know the effect it may cause or whether it is completely removed or not.
Wanna take the risk?