Neutral potassium tartrate

Neutral potassium tartrate is a chemical compound commonly found in the composition of musts and wines in equilibrium with its related acid, known as potassium acid tartrate. The addition of neutral potassium tartrate to a must or wine does not result in the introduction of new chemical elements, but rather induces a shift of potassium ions toward acid, thus creating potassium acid tartrate. The latter has rather limited solubility in hydroalcoholic solutions, and is therefore prone to precipitate as crystals.

The solubility of potassium acid tartrate is affected by the alcohol concentration and temperature of the wine. In general, as alcohol concentration increases and temperature decreases, potassium acid tartrate tends to precipitate, creating crystal deposits within the wine. This phenomenon is known as tartaric instability.

Treatment with neutral potassium tartrate is used to manage tartaric stability in wines. The simultaneous addition of potassium acid tartrate during the wine cooling process allows the growth of potassium acid tartrate crystals to be promoted in a controlled manner. This implies that the crystallization cores already present have better growth. This process helps remove tartrate salts that might otherwise precipitate as unwanted sediment in wine bottles, causing quality and appearance problems.

Compared to deacidification with calcium carbonate, the use of neutral potassium tartrate is preferable as a late intervention because it provides potassium ions to the solution, which can be stabilized more quickly than calcium ions. In addition, it may be a more effective and efficient method to address the problem of tartaric instability in wines.”