Contrary to intuition, you need simpler and thus cheaper equipment to manufacture the more expensive complex greases, than cheaper mono-soap greases.
Calcium grease, the cheapest type, foams badly during saponification in an open kettle. The only way to prevent this is to use a pressure kettle to stop the water boiling.
Next-cheapest is Lithium grease. It foams less, making the cheaper atmospheric vessel a good choice. However, a pressure vessel has the advantage that it keeps water in for longer, raising saponification temperature and speed.
On the other hand, complex greases do not need pressure vessels because complexing happens below the boiling point of water. Furthermore, silica-thickened specialist greases need neither pressure nor heat and are often manufactured in low cost catering mixers.
Is this compelling evidence to prioritise specialist grease manufacture? Apparently not – due to its high demand, low cost and high shear stability, we receive more enquiries for lithium grease plants than for any other type.
Before jumping to the conclusion that Lithium grease is the best product to manufacture, bear in mind that price of Lithium is increasing due to the high demand for Lithium battery manufacture. Is it worth getting a step ahead by manufacturing a non-Lithium alternative?