A water redispersible polymer powder is produced by drying an aqueous mixture of a water insoluble film-forming polymer and a colloidal stabilizer which includes a chelating agent and at least one water soluble polymer. The amount of chelating agent is at least 0.1% by weight, based upon the weight of the water insoluble film-forming polymer, and the amount of the at least one water soluble polymer is at least 0.1% by weight, based upon the weight of the water insoluble film-forming polymer. Dispersions or polymer compositions containing a chelating agent and water soluble polymer as a colloidal stabilizer exhibit an unexpectedly low viscosity which facilitates spray drying and permits use of high solids content dispersions with low pressure spray drying to increase production efficiency. The colloidal stabilizer composition provides unexpectedly superior redispersibility for water insoluble film-forming polymers having very low carboxylation levels.