A reproducible proprietary Advanced Permittivity Testing Method for filtration media, biotextiles and geotextiles is disclosed, which can emulate the devices used at present in these diverse filtration and separation fields. The fluid is passed through the specimen in a series of tests at fixed flow rates and the pressure difference across the media is recorded. The test results permit not only the direct computation of media permitivities, but observation of any pore distortion under fluid-flow conditions. The testing procedure is fully automated.