At about 9 °C above the expected pour point, and for every subsequent 3 °C, the test jar is removed and tilted to check for surface movement.
It is also useful to note that failure to flow at the pour point may also be due to the effect of viscosity or the previous thermal history of the specimen.
It uses automatic apparatus and yields pour point results in a format similar to the manual method (ASTM D97) when reporting at a 3 °C.
The lowest temperature at which movement is detected on the sample surface is determined to be the pour point.
Two pour points can be derived which can give an approximate temperature window depending on its thermal history.
This peculiarity happens because wax crystals form less readily when it has been heated within the past 24 hrs and contributes to the lower pour point.
The sample is then poured into a test jar and immediately closed with a cork carrying the thermometer.