TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Apparatus: The compartments comprise a constriction compartment, a primary reaction compartment, a secondary reaction compartment and a final reaction compartment. The constriction compartment and primary and secondary reaction compartments undergo decrease in diameter with respect to the previous compartment. The final reaction compartment and outlet compartment undergo an increase in diameter with respect to the previous compartment. The inner surface features comprise circumferential ridges, spiral ridges or randomly spaced protrusions or recesses in the walls of the compartments. The impact compartment includes an impact pad.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The methyl- or ethyl-esters comprise biodiesel. The catalyst is sodium hydroxide or potassium hydroxide. The alcohol is methanol or ethanol. The oils or fats comprise canola crude oil, rapeseed oil, soybean crude and soybean degumed oils, and beef tallow, and have 5% or less of free-fatty acid. Preferred Method: The fluidic medium is passed through sequential compartments of progressively smaller diameter, and fluid pressure is decreased to generate cavitational fluid features in the fluidic medium. Alternately, fluidic medium is passed through sequential compartments of progressively larger diameter. The fluid pressure is increased, and fluidic medium is restored to the initial fluid pressure to eliminate cavitational fluid features in the fluidic medium. The fluidic medium is forced around a conical cap positioned in the passageway such that the fluidic medium flows through a narrow circumferential opening. The fluid pressure is decreased to generate cavitational fluid features. Alternately, fluidic medium is passed through orifices in a constrictor plate positioned in the passageway such that the fluidic medium flows through multiple narrow orifices. The fluid pressure is reduced to generate cavitational fluid features in the fluidic medium. The fluidic medium is flowed through a constriction compartment, an inlet orifice, a primary transition compartment having inner surface features, an impact compartment having an impact pad, an outlet orifice and an outlet compartment having another set of inner surface features. The glycerin is allowed to settle out of the methyl- or ethyl- esters. Glycerin is removed from the methyl- or ethyl- esters by centrifuge.