Paints, pharmaceuticals, cosmetics, food, textiles, composites (and filters) are based on formulations involving powders, particles and fibers as well as porous materials. The wettability of powders, particles, fibers and porous materials plays a very important role in the quality, stability and performance of such formulations. Contact angle is the primary parameter used to characterize wetting, but for powders, particles, fibers and porous solids, contact angle determination is complicated by the presence of a porous architecture. However, wettability of samples with porous architecture can be determined by applying liquids to the samples and monitoring the amount and speed of liquid absorption into the sample. Suitable instruments for such absorption and wettability determinations are the Theta Optical Tensiometer and Sigma701/700 Mass Based Tensiometers from Attension.