[1] The main forms of tartrates used commercially are pure crystalline tartaric acid used as an acidulant in non-alcoholic drinks and foods, cream of tartar used in baking, and Rochelle salt, commonly used in electroplating solutions.
Small amounts of pulp debris, dead yeast, and precipitated phenolic materials such as tannins make up the impurities contaminating the potassium acid tartrate.
The exact figures vary according to variety and region, but approximately half of the tartrate soluble in grape juice is insoluble in wine.
The problem is that the tartrate may remain in a supersaturated state after bottling, only to crystallize at some unpredictable later time.
The modern wine industry has decided that tartrate stabilization is preferable to consumer education.