A method of determining liquid absorption of an aggregate comprises providing a sample of the aggregate, adding liquid to the sample, subjecting the sample to a light source signal, monitoring a light reflected signal reflected from the sample and controlling addition of liquid to the sample as a function of the light reflected signal. The apparatus comprises a support for supporting a sample of the aggregate, a liquid source for adding liquid to the sample, a light source which subjects the sample to a light source signal, a light sensor which senses a reflected light signal reflected from the sample and a processor/controller which controls addition of liquid from the liquid source as a function of the reflected light signal. The light source is preferably an infrared source and the light sensor is preferably an infrared detector. The sample is weighed in a dry state and in the saturated surface dry ("SSD") state and the percent by weight of aggregate water absorption and hence aggregate binder absorption and/or bulk specific gravity is then calculated. A weighing device can be incorporated directly into the apparatus.