NOVELTY - Manufacturing fatty acid alkyl esters, comprises determining a flow rate of a feedstock stream (100) to a reactor (110), where the feedstock stream comprises one or more fatty acid glycerides, contacting the feedstock stream and an alcohol stream (102) with a heterogeneous acidic catalyst to produce a reaction mixture stream having a predetermined flow rate from the reactor, where the reaction mixture stream comprises unreacted alcohol, one or more fatty acid alkyl esters, and glycerin, and separating a substantial portion of the alcohol while cooling a portion of the reaction mixture.    USE - The method is useful for manufacturing fatty acid alkyl esters (claimed), and producing biodiesel fuels and biolubricants for automobile applications, mechanical engine applications, cosmetic applications, and soaps.    ADVANTAGE - The method is capable of efficiently manufacturing fatty acid alkyl esters with high yields in an economical manner at mild reaction conditions, thus improving the fuel value and lubricant utility of the fatty acid alkyl esters.    DETAILED DESCRIPTION - Manufacture of fatty acid alkyl esters, comprises: either determining a flow rate of a feedstock stream (100) to a reactor (110), where the feedstock stream comprises one or more fatty acid glycerides, contacting the feedstock stream and an alcohol stream (102) with a heterogeneous acidic catalyst to produce a reaction mixture stream having a predetermined flow rate from the reactor, where the reaction mixture stream comprises unreacted alcohol, one or more fatty acid alkyl esters and glycerin, and separating a substantial portion of the alcohol while cooling a portion of the reaction mixture; or assessing a total amount of fatty acid glycerides and/or a total amount of alcohol in a fatty acid glycerides/alcohol feedstock stream, determining a flow rate of the fatty acid glycerides/alcohol feedstock stream, where the flow rate of the feedstock stream is based on the assessed amount of fatty acid glycerides and/or assessed amount of alcohol in the fatty acid glycerides/alcohol feedstock stream, contacting at least a portion of the fatty acid glycerides/alcohol feedstock stream with one or more catalysts, where at least one of the catalysts comprises an acidic heterogeneous catalyst, obtaining an analysis of a reaction mixture formed from contact of the fatty acid glycerides/alcohol feedstock stream with at least one of the catalysts, where the reaction mixture comprises unreacted fatty acid glycerides, one or more fatty acid alkyl esters, glycerin, and/or unreacted alcohols, assessing a concentration of at least the fatty acid glycerides, at least one of the fatty acid alkyl esters, or glycerin from at least one of the obtained analysis, and adjusting one or more contacting conditions based on at least one of the assessed concentrations. An INDEPENDENT CLAIM is included for a system for manufacturing fatty acid alkyl esters, comprising: at least one mixing device for mixing one or more alcohol compounds and one or more feedstocks, where the feedstock comprises one or more fatty acid glycerides and one or more free fatty acids; a reactor, where the reactor is capable of receiving a flow from the mixing device, and during use, the reactor allows contact of the flow with a heterogeneous acidic catalyst; a device coupled to the reactor, where the device receives flow from the reactor and allows a sudden drop in pressure to induce removal of one or more volatile compounds from the reaction mixture exiting the reactor while maintaining a desired pressure of the reactor, and the reaction mixture comprises one or more of the alcohol compounds, one or more fatty acid alkyl esters, and/or glycerin; and a separator coupled to the device, where the separator is capable of receiving flow from the device, separating at least one alcohol compound from the reaction mixture, and cooling a portion of the reaction mixture.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a method of manufacturing fatty acid alkyl esters.    Feedstock stream (100)    Storage unit (101)    Alcohol stream (102)    Heater (108)    Reactor. (110)