Sustainable approach to achieve total tartaric stability.
Once alcoholic fermentation comes to an end, it’s time to start stabilising wine to prevent defects from appearing in the bottle. One of the most common defects is the appearance of crystals at the bottom of the bottle, generally from potassium bitartrate instability. In recent years, the presence is also due to calcium instability, leading to the precipitation of calcium tartrate.
The increased presence of calcium in wine can be an effect of climate change along with various other sources. Global warming and heat stress lead to an increase in Ca2+ in the vineyard and consequently in must, as well as higher pH conditions that promote instability, influencing the degree of dissociation of tartaric acid and consequently the formation of its calcium salts. Higher calcium levels can also be seen due to deacidification and other winemaking interventions. While the formation of potassium salts can be avoided with the use of protective colloids, calcium stabilisation requires specific interventions.
Stabilising methods
Stabilising methods can be generally categorised in two ways, subtractive and additive.
Subtractive methods have been more traditionally used. They consist of reducing the concentration of tartaric acid, potassium and/or calcium in wine. Most of the substrative methods are usually physical and/or chemical treatments. These can have large energy consumption, high water usage and CO2 emissions. As well as being labour intensive and lead to higher production costs.
The additive approach is a new method that has been growing steadily in recent years due to its multiple oenological advantages. It consists of using protective colloids or crystallisation inhibitors to achieve stabilisation, while being more respectful of sensory qualities and environmentally friendly.
Clues to identify tartaric unstable wines
So which wines are more prone to potassium bitartrate (KHT) and calcium tartrate (CaT) instability?
For KHT instability, all young wines have higher tartaric instability. During the ageing process, wines may naturally stabilise. This depends on several factors, such as the type of wine, storage conditions etc but most wines will show some final instability when analysed.
In addition, when blending different types of wine close to bottling, even if they were previously stabilised, the change in physical-chemical balance could potentially generate instability. When it comes to calcium instability, the situation is more complex since its precipitation is unpredictable. Overtime, several parameters can promote or inhibit this instability.
Promoting factors are high calcium and tartaric acid content and high pH. While inhibitory factors include gluconic acid, malic acid, citric acid, colloids, etc. It is recommended to properly test wines for tartaric instability so necessary stabilisation methods can be implemented.
Enartis stabilisation strategy
Enartis has developed two products to achieve total tartaric stability for the stabilization of potassium bitartrate and calcium tartrate, allowing for a sustainable process, lower production costs, and respecting the quality of the wine.
ENOCRISTAL Ca speeds up the formation of calcium tartrate crystals, promoting their precipitation and reducing the final calcium concentration in wine. It requires 7-10 days of contact time without the need to chill the tank, saving energy and decreasing costs for wineries.
After reaching calcium stability with ENOCRISTAL Ca, rack off and/or filter. The wine is now ready for the addition of ZENITH. This is a product range containing potassium polyaspartate (KPA) that blocks the formation and growth of potassium bitartrate crystals. It maintains the sensory characteristics of wine while preserving acidity, colour, and structure.
ZENITH ensures a lasting stabilising effect, even under suboptimal storage conditions. It can also be applied immediately prior to final filtration.
Looking for further technical support? Reach out to Jennifer Lincoln at Enartis.
Products for tartrate stability are locally available through Itasca Wines.
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