Product description:
Baking powder. Used in a wide range of cakes and slices.
White powder or crystals, soluble in boiling water. Cream of tartar is the common name it is actuallu known as potassium bitartrate, monopotassium tartrate or potassium hydrogen tartrate. It is the potassium acid salt of tartaric acid.

What does Cream of Tartar do?
Cream of tartar has many uses including, stabilizing egg whites, increasing egg whites heat tolerance and volume, preventing sugar syrups from crystallising, reducing discolouration of boiled vegetables, used in combination with baking soda (which needs an acid ingredient to activate it) in formulations of baking powder. Or even used in combination with potassium chloride in sodium-free salt substitutes.