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54 WINES&VINES June 2018 WINEMAKING T wo products that could help wine- makers produce significantly better wines should prompt wineries to seek approval from the Alcohol and To- bacco Tax and Trade Bureau (TTB), which has not fast-tracked these items. The first is Zenith, a colloidal material that will cold-stabilize both white and red wines permanently. Enartis developed the product and introduced it at this year's Unified Wine & Grape Symposium. The second is a bacteria, Lactobacillus plan- tarum, that can consume malic acid to finish malolactic fermentation (MLF) more quickly and completely and with fewer side metabo- lites. L. planetarium is approved internationally for use in wine and in the United States for beer, but not for wine. Zenith Uno and Zenith Color Zenith Uno is for white wines, Zenith Color for red wines. White wines, unlike red ones, must be heat-stabilized prior to addition. K- polyaspartate (KPA) is the functional com- pound of the new colloidal cold-stability agents for use in wine. The chemical process polymer- izes L-Aspartic acid into K-polyaspartate (KPA). More than 14 research and university enti- ties have been involved in research to validate the functionality of this compound in cold- stability. These institutions include universities in France, Italy, Spain, Portugal and Greece. Tartaric-acid crystallization occurs in wine because tartaric acid has the ability to remain temporarily in solution even though it is above its saturation point in an alcohol-water solu- tion. This state is commonly known as super- saturation. The tartaric acid will crystalize and produce glassy-looking crystals in wine when two ions of tartaric acid come close enough to each other. Most frequently, there is some particle (usually potassium bitartrate or KHT) that acts as a nucleation point, causing the ions to exceed the saturation point and crystalize. These ions form the first crystal, which can start a chain reaction to create more crystals. As a colloid, KPA envelops the tartaric acid anion and prevents the ions from getting close enough to precipitate. In trials comparing the most common meth- ods of achieving cold stability, KPA was more efficient as compared to other methods of cold stability. The standard method measures µS, as a determination of conductivity in wine. KEY POINTS Two new products from Enartis will enable winemakers to cold stabilize their wines using a colloidal material known as K-Polyaspartate (KPA). Zenith Uno is for white and light rosé wines and Zenith Color will stabilize dark rosé and red wines. The potassium ion of KPA, a colloid, chelates with the tartaric acid anion and prevents bitartrate anion formation and precipitation over time. KPA has several other benefits: trials have found that KPA does not affect the color of red wines; it is a sustainable product from a water- and energy-consumption standpoint. Meta Tartaric Acid (MTA) and Carboxymethylcellulose (CMC) are two other colloidal com- pounds used for cold stability. Both are temporary means of achieving cold stability that have been shown not to be permanent. A bacteria known as Lactobacillus plantarum has been found to be better at malic acid metabolism than Oenococcus oeni in that it does not produce acetic acid, biogenic amines or carbamates. It is especially useful for wines with a pH above 3.4. Research shows it is best to co-inoculate L. plantarum with the primary alcoholic fermentation organisms. Cold Stabilization and Malolactic Fermentation Commentary: A call to action By Richard Carey Figure 1: When CMC and KPA (Zenith Color) were added to stabilize Shiraz wine, KPA did not react with anthocyanins and the wine retained its color. K-POLYASPARTATE: PERFORMANCE STABILIZING SYNERGIES Application trials: Shiraz 2017 — 6 days at -4°C Control CMC + Verek GA KPA + Verek GA