Potassium tartrate

Description

Potassium tartrate, dipotassium tartrate or argol has formula K₂C₄H₄O₆. It is the potassium salt of tartaric acid. It is often confused with potassium bitartrate, also known as cream of tartar. As a food additive, it shares the E number E336 with potassium bitartrate.

Chemical Properties

white crystalline powder

Uses

Manufacture of potassium salts, medicine (cathartic), lab reagent.

Uses

Potassium tartrate is the acid potassium salt of tartaric acid occurring as crystals or powder. It is relatively poorly soluble having a solubility in 100 ml of water at 0.8 g at 25°c and 6.1 g at 100°c. A 1% solution at 30°c has a ph of 3.4. Chemical names are potassium acid tartrate, potassium hydrogen tartrate, and potassium bitartrate. It functions to complex with heavy metal ions and to regulate ph; it can have a gentle laxative action if given at adequate levels. The acidulant is used in chemical leavening to release carbon dioxide which produces the loaf volume. It has limited reactivity in the cold so when used in reduced-temperature batters it has little gas evolution during the initial mixing. At room temperatures, it has a relatively fast reaction rate. It functions as a taste regulator in sugar icing and in controlled crystallization of toffees and fondants by the regulated inversion of sucrose. It is used in baked goods, crackers, candy, and puddings.

Preparation

Potassium tartrate is produced by the reaction of tartaric acid with potassium sodium tartrate (rochelle salt), and potassium sulfate, followed by filtration, purification, precipitation and drying.

Definition

ChEBI: The potassium salt of L-tartaric acid.

Flammability and Explosibility

Not classified

Purification Methods

Recrystallise it from distilled water (solubility: 0.4mL/g at 100o, 0.7mL/g at 14o). [Beilstein 3 IV 1223.]