TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - The performance enhancer is selected from cold flow additives, cloud point depressants, biocides, conductivity improvers, corrosion inhibitors, metal deactivators, and/or engine cleaning agents. The antioxidant is selected from amine-based antioxidants, phenolic antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, zinc dithiophosphate, and/or oil-soluble copper compounds.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: In the method, where the processor calculates at least four fatty acid alkyl ester mass percentage ratios and algorithmically determines the volumetric percentages of at least four fatty acid alkyl esters. The processor is optionally neural network which uses associative memory to generate algorithms that determine the volumetric percentages of at least one fatty acid alkyl ester. The analyzer is gas chromatograph, gas chromatography microchip, gas-liquid chromatography microchip, micro-gas chromatograph, mass spectrophotometer, gas chromatograph-mass spectrophotometer, liquid chromatograph-mass spectrophotometer, ion mobility spectrophotometer-mass spectrophotometer, ultraviolet-visible absorbance spectrophotometer, infrared (IR) absorbance spectrophotometer, UV fluorescence spectrophotometer, mid-infrared (MIR) absorbance spectrophotometer, near infrared (NIR) absorbance spectrophotometer, X-Ray fluorescence (XRF) spectrophotometer, nuclear magnetic resonance spectrophotometer, micro-oscillation spectrophotometer, micro-distillation-spectrophotometer, micro-mass spectrophotometer, or micro-ion mobility spectrophotometer. The processor is programmable logic controller. The biofuel is a biodiesel or a biodiesel blend and the volumetric percentages of the fatty acid alkyl esters are correlated to reference biodiesel feedstock triglyceride profiles and the biodiesel's feedstock, or the feedstock of the biodiesel component of the biodiesel blend, is determined. The fuel performance data represents values indicative of properties selected from lubricity, specific gravity, kinematic viscosity, flash point, boiling point, cetane number, cloud point, pour point, lubricity, and copper strip corrosion. The method further involves: (a) determining total mass percentages of saturated, monounsaturated, and polyunsaturated fatty acid alkyl esters in the component; and (b) inputting values indicative of the total mass percentages of saturated, monounsaturated, and polyunsaturated fatty acid alkyl esters into the processor with preprogrammed instructions (1) calculates (i) at least one fatty acid alkyl ester mass percentage ratio (ii) ratios of the mass percentage of each of at least two fatty acid alkyl esters and the total mass percentages of saturated, monounsaturated, and polyunsaturated fatty acid alkyl esters (2) algorithmically determines the volumetric percentages of at least one fatty acid alkyl ester in the component using the at least one fatty acid alkyl ester mass percentage ratio, the total mass percentages of saturated, monounsaturated, and polyunsaturated fatty acid alkyl esters, and ratios of the mass percentage of each of at least two fatty acid alkyl esters and the total mass percentages of saturated, monounsaturated, and polyunsaturated fatty acid alkyl esters as algorithmic independent variables. The method involves: submitting sample of fatty acid alkyl ester-containing component of the biofuel to analyzer which (1) measures the mass percentages in the component of at least two fatty acid alkyl esters (2) contains processor with preprogrammed instructions (i) calculates at least one fatty acid alkyl ester mass percentage ratio and algorithmically determines the volumetric percentages of at least one fatty acid alkyl ester in the component using the fatty acid alkyl ester mass percentage ratio as algorithmic independent variables (ii) correlates the fatty acid alkyl ester volumetric percentages to fuel performance data and generates output signal indicative of that correlation; and (b) controlling blending of the biofuel in response to the processor output signal. The compositions selected from petroleum distillate, cetane improver, performance additive, and antioxidant are blended with the biofuel in response to the processor output signal. The analyzer measures the mass percentages of methyl esters of palmitic acid (16C:0), palmitoleic acid (16C:1), oleic acid (18C:1), and linoleic acid (18C:2); (c) the processor calculates the following mass percentage ratios: (1) linoleic acid methyl ester: oleic acid methyl ester; (2) oleic acid methyl ester: palmitic acid methyl ester; (3) palmitoleic acid methyl ester: palmitic acid methyl ester; and (4) palmitic acid methyl ester: oleic acid methyl ester; and (d) the processor determines the volumetric percentage of: (1) soybean oil methyl ester; (2) rapeseed oil methyl ester; (3) tallow oil methyl ester; and (4) palm oil methyl ester. The linoleic acid (18C:2) is linoleic acid (18C:2 cis 9, 12); and the oleic acid (18C:1) is either oleic acid (18C:1 cis 9) or oleic acid (18C:1 trans 9). The processor determines the volumetric percentage of soybean oil methyl ester (SME), rapeseed oil methyl ester (RME), tallow oil methyl ester (TME), palm oil methyl ester (PME), coconut oil methyl ester (CME), and jatropha oil methyl ester (JME) using two sets of algorithms as given in the specification. The biofuel is a biodiesel blend that comprises biodiesel (2-98 vol.%) and petroleum distillate (2-98 vol.%). Preferred Components: The biofuel is jet biofuel comprised of fatty acid alky esters. The biofuel is a biodiesel or biodiesel blend and the processor determines the volumetric percentage of at least one composition selected from soybean oil alkyl ester, rapeseed oil alkyl ester, palm oil alkyl ester, canola oil alkyl ester, sunflower oil alkyl ester, olive oil alkyl ester, corn oil alkyl ester, tallow oil alkyl ester, coconut oil alkyl ester, jatropha oil alkyl ester, yellow grease alkyl ester, animal fat alkyl ester, and used cooking oil alkyl ester. The biofuel is a biodiesel or biodiesel blend and the analyzer measures the mass percentages of at least four alkyl esters of fatty acids selected from myristic acid (14C:0), palmitic acid (16C:0), palmitoleic acid (16C:1), stearic acid (18C:0), oleic acid (18C:1), linoleic acid (18C:2), linolenic acid (18C:3), eicosanoic acid (20C:0), eicosenoic acid (20C:1), docosanoic acid (22C:0), and docosenoic acid (22C:1). The cetane improver is selected from 2-ethylhexyl nitrate, cyclohexyl nitrate, di-tert-butyl peroxide, methyl nitrate, ethyl nitrate, n-propyl nitrate, isopropyl nitrate, allyl nitrate, n-butyl nitrate, isobutyl nitrate, sec-butyl nitrate, tert-butyl nitrate, n-amyl nitrate, isoamyl nitrate, 2-amyl nitrate, 3-amyl nitrate, tert-amyl nitrate, n-hexyl nitrate, 2-ethylhexyl nitrate, n-heptyl nitrate, sec-heptyl nitrate, n-octyl nitrate, sec-octyl nitrate, n-nonyl nitrate, n-decyl nitrate, n-dodecyl nitrate, cyclopentylnitrate, cyclohexylnitrate, methylcyclohexyl nitrate, isopropylcyclohexyl nitrate, 1-methoxypropyl-2-nitrate, 1-ethoxypropyl-2 nitrate, 1-isopropoxy-butyl nitrate, and/or 1-ethoxylbutyl nitrate. EXAMPLE - No suitable example given.