TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: Increasing the throughput of esterification or transesterification reactions of biodiesel fuel production, involves: separating and removing glycerin from the reaction product of a biodiesel feedstock and an alcohol; gathering a portion of the reaction product after the glycerin has been separated and removed; and causing a single phase solution to be formed of the biodiesel feedstock and the alcohol by: recycling the gathered portion of the reaction product containing a methyl ester to form the single phase solution at a given temperature and pressure, to a mixing unit; and maintaining the mixing unit at the given temperature and pressure thereby forming a single phase solution of the biodiesel feedstock, alcohol, and recycled reaction product in the mixing unit. Providing the methyl ester involves gathering the methyl ester from an output of the reactor unit or an element coupled to it and recirculating the methyl ester to an inlet of the mixing unit. The reaction constituents comprise methanol and triglyceride with at least 15% of the proportion of the total input to the mixing unit being methyl ester and where the mixing unit is maintained at at least 60degrees C and at least atmospheric pressure. The pressure and temperature are maintained as the same throughout the reactor unit. The single phase solution output from the mixing unit flows through a heterogeneous catalyst in the reactor unit. The method further involves: supplying a catalyst containing dry sodium methylate in methanol as part of the reaction constituents to the mixing unit; and passing the output from the reactor unit through a dry wash system comprising ion-resin beads, the ion resin beads converting a soap within the output to free fatty acid and adsorbing any remaining of the supplied catalyst. The method further involves: supplying the triglyceride as a reaction constituent to the mixing unit; and removing water from the triglyceride prior to supplying the triglyceride as a reaction constituent to the mixing unit. The method further involves removing water from the reaction constituents. Removing water involves distilling the reacted constituents after they have passed through at least one reactor unit. The reactor unit performs esterification or transesterification and where the method further involves separating glycerine from the reacted constituents after they have passed through the reactor unit. The method further involves removing glycerin from the reacted constituents after they have passed through the reactor unit and where the methyl ester is gathered from the reacted constituents after they have passed through the reactor unit and the glycerin has been removed. In method, a first mixing unit and reactor unit are provided and where high free fatty acid feedstock is processed in it, and where a second mixing unit and reactor unit are provided and low free fatty acid feedstock is processed in it. EXAMPLE - No suitable example given.