TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Process: The flash vessel is operative to recover at least 50 (preferably at least 75)% (volumetric) of the unreacted alcohol that is present in the forwarded stream. The pressure of the forwarded stream is reduced by at least 50 (preferably at least 100) psig to vaporize the unreacted alcohol. The flash vessel operates at 100-275 degrees F. The forwarded stream is maintained at a pressure of at least 50 (preferably 100-250) psig until the pressure is reduced to vaporize the alcohol; and a temperature of 150-350 degrees F. The glycerol enriched stream is forwarded to the flash vessel. The fatty acid ester enriched stream is forwarded to the flash vessel. The method of recovering unreacted alcohol from biodiesel ester reactors, comprises: reacting triglyceride and methanol in a first reaction zone under pressure to form an intermediate mixture comprising glycerol, unreacted reactants, and fatty acid methyl ester product; treating the intermediate mixture with a separation means to generate a first glycerol enriched stream and a first fatty acid methyl ester enriched stream, and passing the first fatty acid methyl ester enriched stream to a second reaction zone; reacting the first fatty acid methyl ester enriched stream with a fresh feed of alcohol in the second reaction zone to form a second intermediate mixture which includes fatty acid alkyl esters, glycerol and unreacted reactant; treating the second intermediate mixture with a second separation means to generate a second glycerol enriched stream and a second fatty acid methyl ester enriched stream; forwarding either or both of the first glycerol enriched stream, and the second fatty acid methyl ester enriched stream to a flash purification vessel, which includes a condenser in the upper portion of the vessel; reducing the pressure of the forwarded stream in the flash purification vessel and maintaining the temperature of the stream at a level such that the methanol vapor is flashed off of the liquid product stream, for producing a methanol-depleted stream; condensing the methanol vapor in the condenser, and sequestering the condensed methanol from the methanol-depleted stream; and recycling the condensed methanol to at least one of the reaction zones. The flash purification vessel operates at a pressure of -2 to -10 psig. In the continuous method of making and recovering unreacted alcohol from biodiesel ester reactors, the pre-reactor triglyceride feedstock includes organic fats, oils and/or greases; the pre-reactor triglyceride feedstock is heated by at least 25 degrees F in the condensing unit; the pre-reactor triglyceride feedstock is heated at 150-450 degrees F in the condensing unit; a portion of the heated triglyceride feedstock stream exiting the condensing unit is sent directly to the reactor and a portion of the heated feedstock stream is sent to storage; each of the pressurized streams is forwarded to separate flash vessels; and both of the steams from step (e) are forwarded to separate flash vessels. Preferred Components: The flash purification vessel further includes a reboiler, which heats the methanol-depleted stream. The flash purification vessel includes trays and/or packing material. EXAMPLE - None given.