Abstract: A method for controlling the setting of a cementitious composition of matter, the present invention allows mixing of a mortar and retention thereof for a prolonged period of time before use, the mortar setting at least as rapidly as normally when applied to brick, block, or the like during the period of retention. The method involves the addition of an effective amount of saccharide polymers having a size of from three glucose units to on the order of 25 glucose units to a cementitious mixture, the additive optionally including air entrainment agents and similar agents such as have been previously used in the formulation of mortars. The method further involves entraining air in the mortar mixture to a particular degree which allows control of the setting rate of the mortar mixture when evaporation from the mixture is controlled.