Kinematic viscosity is measured in "Stokes". You cannot measure it at home without a viscosimeter. There is a comparative way, though. Take a liquid with a known viscosity value (petroleum heating oil, look the value up in an engineering manual) and let a known volume flow through an upside-down plastic water bottle with a drinking straw glued in a hole in the screw top. Check the time it takes with a stopwatch. Do the same with your biodiesel (same volume) and compare the results. Generally a smaller diameter straw will produce more accurate results. If the time of your sample is the time of your control sample (petroleum oil), this means its viscosity is roughly -ish that of the control sample. -- Aleks Kac, 6 Nov 2001 .