Com. glucose syrups with a high content of crystd. sugars as well as its equiv. with a low content of crystd. ones and their dild. aq. solns. were tested by using a rotational rheometer (18-50 degrees C, shear rate 1-30 s(-1)) to identify the Newtonian liqs. with a viscosity 2-15 Pa.s. At 20-24 degrees C, only syrup with low content of crystd. sugars was a non-Newtonian liq. and should not be used to characterize the gear pumps.