Methods for Determining Fluid Properties

Disclosed herein is a method for determining two or more properties of a blended biofuel fluid sample, the method comprising measuring a complex impedance of the sample at each of a plurality of frequencies to produce a sample data set, determining a biofuel blend percentage of the sample using the sample data set; and determining at least one additional property of the sample based upon the determined biofuel blend percentage. In another aspect, a biofuel blend percentage of the sample can be determined using an algorithm developed using a data gathering and data mining technique relating measured impedance spectroscopy data from a plurality of samples to biofuel blend percentage values determined using a standard analytical measuring method for biofuel blend percentages.