Ensuring that wine is physically stable and can be transported, stored over time and served, while always remaining in perfect condition is hugely important in today’s modern, global wine market.
For those who remember their high-school science classes, acids and non-metal ions combine into compounds called salts. With variations in temperature, salts have a propensity to precipitate out of solution, forming crystals. Because such crystals are not well understood by the wine-drinking public and can be seen as very undesirable, achieving tartrate stability is one of the most important steps in the production and packaging of wine.
The most significant non-metal salts concerning winemakers are potassium bitartrate and calcium L-tartrate. Commonly, tartrate stability has been achieved by subjecting the wine to an extended period at a temperature lower than it is likely to experience at any time as a consumer product. This allows as many tartrates as possible to precipitate out of solution, prior to the wine even being bottled.
In former times, before refrigeration, nature would lend a helping hand. Cold temperatures in the cellar over winter would precipitate acid salts, allowing relatively stable wine to be racked off and sold in spring. In more recent times, refrigeration has been used to drop the temperature of a tank of wine to approximately two degrees Celsius, to achieve a good, practical level of shelf-stability. Latterly, additives such as carboxymethyl cellulose have been said to physically prevent precipitation, without removing either the acid or non-metal ions and usually achieving sufficient stability for low-cost wines or wines that don’t require a particularly long shelf life.
Traditional cold-stabilisation is relatively effective but very inefficient, requiring up to 0.3KWh of electricity to stabilize each litre of wine.
Vintech Pacific’s STARS Electro-Dialysis is both extremely effective and highly efficient. STARS (Selective TArtrate Removal System) works by moving micro-layers of wine between two membranes which are selectively permeable, one to tartrate anions, and the other to potassium and calcium. A water-based conductant flows past the other side of each membrane and a weak electrical field attracts the tartrate salts towards the anode, migrating them through the membrane to be carried off by the conductant solution, which is discarded. Meanwhile, potassium and calcium cations are attracted towards the cathode, pass through the membrane and are likewise carried off and discarded with the conductant solution. The concentration of tartrate anions, potassium and calcium is reduced in the wine, rendering it immediately and permanently tartrate stable.
With STARS, energy consumption is drastically lower when compared to cold stabilization and requires no chemical additions.
Vintech Pacific’s STARS units provide a very effective tool for…
- Adjusting pH and/or TA with No Additives
- Preserving Low TA
- Potassium Stability
- Calcium Stability
- Stability on Demand at Bottling Temperature
- Reducing Sulphur Levels (up to 35% in whites)
- Removing Chloride
- Energy Savings (up to 90%)
For more information, please contact…
Vintech Pacific Wine Technologies
Phone: 06 863 0028
Mobile: 021 783 236