The stickiness of cotton is determined by testing a cotton sample at two or more temperatures. Sticky deposits are recorded at a lower temperature, preferably 27° C. or 34° C., to detect the trehalulose-rich honeydews droplets. Then, the sample is subjected to a higher temperature, preferably 54° C., to detect the non trehalulose-rich honeydew droplets and physiological sugars. By comparing the results at these two temperatures, an accurate grading system for cotton may be produced which can help growers and spinners accurately identify different types of cotton and determine processing problems.