Efflorescence of masonry construction is a natural occurrence when masonry is constructed in other than normal conditions. Early age efflorescence may occur shortly after construction has been completed; late age efflorescence may occur if design and construction considerations and building maintenance are not properly attended. Efflorescence, once understood, is deemed beneficial toward identifying problems associated with building performance and indicating corrective action to be taken to remedy the situation. An efflorescence test method for masonry mortars has been developed. The method is considered beneficial for isolating contributors toward efflorescence, be it adverse exposure conditions, cement retarders, or contaminated individual materials. The interpretation of test results allows isolation of contributing factors and remedial action. Practically, testing of masonry mortars will not guarantee that efflorescence will not appear on the surface of a structure. -- AATA