0 CALORIES CRYSTAL STEVIA COMPOSITION : ERYTHRITOL, STEVIOL CLYCOSIDES,REB-A 98.7% refers to the purity of Reb-A used to make the stevia extract powder. The sweetness ratio is 1:5 which means that 1kg packet is equivalent to 5kg of sugar! Rebaudioside A 98.7% is derived from Stevia rebaudiana Bertoni, an herb in the chrysanthemum family that is native to parts of South America. Rebaudioside A is the more potent and pleasant tasting of the two major extracts of the stevia plant, known as steviol glycosides. Rebaudioside A is widely consumed as a sugar alternative that can be mixed with other sweet natural products, such as honey. It is heat stable and can be used for cooking and baking. Our Rebaudioside A powder has a sweet, clean taste, with no undesirable features or unpleasant after taste..