A method of characterizing and monitoring a fermentation process includes acquiring online Raman spectra of a fermentation process within a fermenter vessel at different times during the fermentation process to generate a training data set; acquiring physical samples from fermentation process near in time to the acquired Raman spectra; performing offline measurements of the target analyte properties and/or compositions using an assay measurement technique; generating a correlative model of the target analyte such that spectral changes in the training data set correlate with the offline measurements of the target analyte properties and/or compositions; acquiring online Raman spectra of a subsequent run of the fermentation process within the fermenter vessel at different times during the run to generate a process data set; and applying the correlative model to the process data set to qualitatively and/or quantitatively predict a value of a property and/or composition of the target analyte.