A method of predicting the stability of a hydrocarbon process stream is disclosed and claimed. The method includes obtaining samples from one or more process streams and measuring the actual stability and the near infrared spectral absorbance of those samples. A classification model is initially developed to identify sample subsets and correlation model is created using the stability and absorbance data by inserting that data into a mathematical function. Online or offline measurements are then taken from the hydrocarbon process stream, the classification model is used initially to identify the subset and corresponding correlation model is used to predict the stability of the stream.