Cream of tartar is an acid salt, potassium hydrogenate tartrate
(K C4 H5 O6), that...
- increases the heat tolerance and volume of egg whites when beaten.
- prevents sugar syrups in candy and icing making from crystallizing.
- impedes discoloration in boiled vegetables.
- is frequently a principal component of baking powder along with
sodium acid pyrophosphate. Combined with baking soda it
becomes baking powder.
- is an excellent metal cleaner especially when combined with vinegar.
- occurs naturally as a pure ingredient left over from the fermentation
of grape juice although brown-red in color. Processing turns it white.
- has no aroma, but an acidic flavor.
Use cream of tartar to make meringue or in beating egg whites for other
reasons, especially for mousse au chocolat.
It helps protect the whites while heating to 145° greatly reducing any
potential harm from uncooked egg in the recipe. Add the cream of tartar about
halfway through the beating process to ensure that the volume increase gets
started first.