The POTASSIUM BITARTRATE, better known as CREAM OF TARTAR, is an acid salt present in grapes and wine. Everybody knows these crystals that settle at the bottom or lengthwise inside the bottles of wine. Neophytes think that this is sugar. Obviously this is not the case: if you taste them you will realize that they are tasteless. They are crystals of potassium bitartrate precipitated after wine cooling. These crystals do not alter wine and their presence is nothing abnormal: they represent a natural product, also present as tartar, on the tanks' and casks' walls.To avoid these deposits the wine-maker lets the wine settle, before bottling, in a big tank at a temperature of about 4°C. In that way potassium tartrate precipitates and settles at the bottom of the tank in the form of crystals. If wine doesn't undergo this cooling treatment, or if the bottle is cooled at a lower temperature than wine in the tank, the precipitation occurs in the bottle.

The CREAM OF TARTAR is mainly used as a natural adjuvant in the rising of cakes and in the enological industry refrigerators.

The CREAM OF TARTAR is included in the list of the FOOD ADDITIVES permitted under the code E 336 in the following classes:
- ANTIOXIDANTS (to stop the food deterioration caused by contact with the oxygen in the air)
- BAKING POWDERS