Traceability and Transparency: The New Frontier for Winemaking and Its Impact on Tartrate Stabilization?

The new ‘wine frontier’ for oenological or winemaking seems to be moving towards the production of better quality wines with increased traceability and more transparency of ingredients for the consumer. 

Consumers are demanding more information about the products they are consuming

Providing more information and changing labeling practices in general has been a divisive issue within the wine industry both in Europe and the US for many years. Alcoholic beverages (wine, beer, cider, spirits), are not, at this time, subject to the labeling of additives like other prepackaged foods (EU Regulation No.1169/2011 on the provision of food information to consumers) except in cases where there is a risk of allergies, e.g. the addition of sulfites.  Consumers in Europe, however, have been putting increasing pressure on the EU Commission to demand from wine producers clear and easy to understand information about calorific intake and ingredients so that they can make informed decisions about the products they choose to consume in a bid to live a more balanced lifestyle. There is no reason to believe that this trend will be any different in the US.

In 2018, in response to that increased pressure and after months of intensive talks with the EU Commission, the European Beverage Industry, offered up a self-regulating proposal pertaining to information provided to consumers.   In the proposal, they agreed to provide the nutritional information and the list of ingredients of their products.

The self-regulatory proposal, while not required to abide by the legal framework laid down in Regulation 1169/2011, will enrich the information provided to consumers by going beyond the current legislative framework.  The move seems to be an indication that the industry worldwide, including the US, will, at some point, have to bow to consumer pressure and offer up a list of all wine additives, as well as the caloric output of wine as part of the labeling information shared by producers with their consumers.  What additives and how many, is going to become a much larger question for winemakers in the future.

Demand for “zero fault” wines with or without additives

With trade across international markets, additional conditions are placed on wine producers that go well beyond the main criteria of taste and variety.  The demand is for almost perfect wines, in terms of visual attributes, oxidation, turbidity and a zero tolerance for deposits at the bottom of the bottles. 

However, given the composition and ionic richness of the grape berry in potassium, calcium and tartaric acid in conjunction with alcoholic fermentation which decreases the solubility of potassium hydrogen tartrate, tartar deposits are inevitable without the intervention of the oenologist.  To achieve zero fault, winemakers are required to reduce or even suppress the sulfiting of wines; knowing that, in general, for each filtration, clarification or stabilization treatment operation, the sulfite content is traditionally re-adjusted.  At the same time, every wine transfer causes the dissolution of the oxygen of the air and therefore, it is likely to be subjected to a subsequent addition of sulfites anyway. 

Stabilizing the wine and preventing the tartar deposits without impacting the visual attributes, organoleptic characteristics and overall quality of the wine has become imperative.  Therefore, the process used in stabilizing the wines plays a primary role in addressing those demands for a near perfect wine every time. 

What approaches can be used for Tartaric Stabilization: Oenologists have really three main methods available to them to stabilize wines; cold stabilization; additives, and technological processes such as resins or membranes.  

To improve quality, winemakers can count on 3 main methods to stabilize wines:

Cold stabilization is the most traditional and most widespread method used.  Utilizing refrigeration to create the conditions for crystallization and deposition of the crystals. Experience shows that the more the wine is rich in macromolecules, polysaccharides, polyphenols in particular, the more the effectiveness of the cold treatment is limited by a protective colloid effect.  The cold wine treatment leads simultaneously to the stabilization of the colloidal dystuff of young wines.  The energy cost and especially the loss of wine are disadvantages that question this process in the context of renewal of equipment and/or new investments.

Additives, as their specification indicates, are there to help achieve better stability.  More and more additives are being allowed.  Potassium polyaspartate, being the latest, was approved in Europe by the OIV in October 2016 (resolution OIV-OENO 543 2016 but has not yet been approved for use in the USA) and joins a list of others: carboxymethylcellulose, or CMC known in oenology as cellulose gum, yeast extracted mannoproteins, metatartaric acid for the oldest of them and various other ingredients and stabilizers of animal or vegetable origin. Oenological potassium polyaspartate is exclusively prepared from L-aspartic acid, which is produced by bacterial fermentation (Bacillus); the fact that L-aspartic acid is derived from genetically modified organisms (GMO) must be marked on the packaging label of potassium polyaspartate.  Moreover, unlike other wine additives, which were previously authorized in the agriculture/food industry, thus far, potassium polyaspartate has been utilized only in the field of chemistry as a sequestering agent, included, for example, in sodium dishwashing tablets, although it was added to the list of food additives at the OIV in October 2016 (OIV-OENO Resolution 543-2016) which opens up its approval for oenological practice in EU countries.  The first experiments at the producer stage are still in progress, but like all the other additives of stabilizing type, once incorporated into the wine matrix, it can generate disorders in certain wines, especially in red wine, with a lesser effectiveness for tartaric stabilization. It contributes to the acquisition of stability, but excessive dosing can induce an increase in turbidity (OIV-OENO Resolution 543-2016).

Membrane electrodialysis technology  is based on the extraction of both the anions and the cations of the wine which generate the crystals: in particular potassium, calcium and tartrate ions.  The electrodialysis membranes are not porous, they are sort of ion separators (the wine does not cross them), and the driving force of separation is not the pressure, but a low voltage. The challenge is using the membranes to eliminate only the excess ions so that they do not settle regardless of the duration and storage temperature of the wine.  A predictive test which takes just 4 hours is carried out to calculate the conductivity of the wine which corresponds to the cold saturation equilibrium (-4° C for example) for an almost infinite time. Thus, only the quantity of ions necessary and sufficient to obtain stability is extracted from the treated wine, and this is done without loss of wine volume and with a guarantee of stability. It should be noted, that in the USA, electrodialysis is qualified to treat organic wines, since no additives are added to the wine.  The process is now continuous, automated, is suitable for all types of wine (and grape juice) and the water required for the process can now be widely recycled. The units are compact and allow online processing from the tank by minimizing oxygen dissolution.

Whatever the method chosen by winemakers to stabilize wines in the future, it is inevitable that consumer demand for more transparency will have a role to play in that decision?

The tartaric stabilization strategies and the choice of technologies will be dictated by the distribution and marketing conditions for the wines (geographical destination of the shipment, distribution cycle, specifications of the importers, export regulations), the wines typology (color, breeding wines, degree of instability, technical preparation-conditioning itinerary, acid-base balance), the stabilization costs (with regard to the category of wines and their market segment) and the ethical considerations of production (environmental impacts, the desire to limit inputs and to favor products naturally present in wine, non-GMO origin).

The growth in the number of recently authorized additives brings up new questions and concerns for the consumer. Alcoholic drinks of more than 1.2% vol. (wine, beer, cider, spirits) are not, as previously mentioned, subject to the labeling of additives such as other prepackaged foods (EU Regulation, No. 1169/2011, consumer information, except in case of risk of allergy: eg the addition of sulfites).   The European Commission’s report, however, reveals that the majority of consumers are waiting for such information according to a survey conducted in 2014, at the request of a brewing association, in six states with 5,600 respondents. Consumer representatives argue that the inconsistency between the labeling of alcoholic beverages and that of other pre-packaged foods is unacceptable, and that the list of ingredients and the nutrition declaration should be mandatory for all alcoholic beverages in order to enable consumers to make informed choices about what they are drinking, and in what quantity.  

At the international level, the Codex Alimentarius Standard for the Labeling of Prepackaged Foods do not exempt alcoholic beverages from the mandatory ingredient list provision.  In several countries such as Canada, Brazil, China, New Zealand, India, Mexico, Russia, Switzerland and including the United States, the list of ingredients is mandatory for certain alcoholic beverages.  If such exposure were required for wine, it is likely that this would have a strong impact on the strategies and the technological processes used for wine stabilization treatments.   

Only time will tell on the wine labeling issue at the US and international level, but in the meantime, you cannot help but wonder what tomorrow’s filtration, clarification and stabilization treatments will look like?