Mixing a frictional solid powder into a liquid to form a paste is a powerful way of forming a solid object. Products made in this way include bricks, tiles, fertilizers, foods, pharmaceuticals, and catalysts. Additives are included to give (i) green strength for processing after extrusion or molding, (ii) strength to the final fired product, and (iii) necessary final properties. The selection of a liquid phase, its amount, its suitability, and amount of additives then become critical issues. In particular the paste must be formulated so that problems do not arise due to liquid phase migration. A methodology has been developed to evaluate liquid phase migration. It is studied for a range of both ceramic pastes and gels typical of some seen in the manufacture of catalysts. A constant pressure is imposed on the material in a cylindrical ram, and the unsteady state drainage of liquid through a porous end plate is followed. This volume is proportional to the square root of time for most of the process, the constant of proportionality leading to a characterizing desoiptivity. After a brief time lag, gels made by acidification of boehmite behaved similarly. Studies on model pastes made from alumina particles, water, Bentonite clay, plus a carbohydrate or starch revealed that liquid phase migration was enhanced by an order of magnitude if Bentonite clay were absent. It was significantly reduced if dextrin rather than glucose or lactose was an additive. The desorptivity permits ranking of the migration rates and shows when other work is needed to understand the origin of behavior.