Tartrate Stability in White Wines

Change and innovation are critical for keeping up with wine industry trends, as well as improving your winery’s efficiency, sustainability, and bottom line.

There is a plethora of ongoing research looking at improvements in all aspects of winemaking and viticulture. Today, I’d like to highlight a recent study looking at one such improvement. Specifically, I’ll be discussing a research article that focused on alternative methods for tartrate stability in winemaking, which currently is time and energy intensive.

Since many of you are winemakers, and all of you are in the wine industry in one way or another, you are likely already familiar with what tartrate stability is and why it’s done. If the wine does not undergo tartrate stability, there is a risk of tartrate crystals precipitating in the bottle, which has been shown to have a negative effect on consumer sales. Though there is nothing wrong with a wine with tartrate crystals, the average consumer often does not understand what these crystals are and assumes the wine is bad.

The most common and simplest method of tartrate stability is cold stabilization. By subjecting the wine to cold temperatures for over two weeks, the costs to the winery and to the environment are significant. There are other methods used for tartrate stability that are less common, such as ion exchange or electrodialysis, however, these methods are costly and require significant knowledge of other processes to perform them correctly.

These issues inspired researchers to study other possible alternatives to the currently available tartrate stabilization methods that are more efficient and cost-effective. Specifically, they examined the effectiveness of plasma polymerization on tartrate stabilization in wine.

Plasma Polymerization

What is plasma polymerization? Briefly, it is “used to add nanoscale thin coatings containing chemically reactive functionalities onto otherwise non-reactive substrates.” (Mierczynska et al, 2023). In plain English, you can add a substrate containing a layer or coating of something that contains compounds that will bind to the compound in the wine that you want to get rid of. Then, you can remove this complex from the wine, thus removing the compound you are trying to get rid of – in this case, excess tartrates.

Plasma polymerization technology is well-known in many different fields and is known for its speedy performance, cost-effectiveness, and environmental friendliness. Specifically, plasma polymerization can be performed using energy from wind turbines or solar panels, making the process much more sustainable (and much faster!) than the current cold stabilization methods.

Study Methods

In order to test the effectiveness of plasma polymerization technology on tartrate stabilization, Mierczynska et al (2023) experimented with several different white wines: cold and heat-unstable Muscat Gordo, Sauvignon Blanc, Chardonnay, and Pinot Grigio, as well as cold-unstable Muscat Gordo wines that were fined with bentonite.

For plasma polymerization, a special custom-built reactor with a 13.56 MHz plasma generator was employed. The coatings that were created in this reactor were rich in amine, carboxyl, and oxazoline groups, as these chemical compound groups were hypothesized to attract and subsequently remove the excess tartrate as it developed in the wine.

After the wines were treated with the plasma complexes, many chemical parameters were measured, including basic wine chemistry, tartaric acid levels, crystal levels, protein concentration, and metal content analysis.

What the Results Found

The results of the plasma polymerization treatment on the study wines showed that using plasma-polymerized acrylic acid, allylamine, and oxazoline were all effective in removing tartrate crystals (specifically in the form of potassium bitartrate) from the cold and heat-unstable wines at a temperature of 15oC (~60oF).

Out of the three polymerized plasmas, the allylamine composite was the most effective at removing tartrate crystals from the wines with a removal rate of 98%, followed by oxazoline with a removal rate of 96%, and finally acrylic acid with a removal rate of 93% after a storage time of one month. After one week, the allylamine plasma composite had a removal capacity of 64%.

Commercial Applications

Overall, the study showed that using plasma polymerized compounds with an affinity to adhere to tartrates (specifically potassium bitartrate in this experiment) was effective at removing the excess tartrates from the wine, thus performing the same function as cold stabilization but at a higher temperature (60oF instead of 32oF, or as close to freezing as possible). This would lead to significant energy and cost savings for the winery and the environment since it obviously doesn’t take as much energy to keep a room at 60oF as it does to keep the room at 32oF.

Is this type of technology available yet commercially? Not yet. It is still in the research phase, but every new technology needs to start in the research phase, and this research shows great promise for another method for tartrate stability other than cold stabilization, and hopefully, with time, commercially available equipment and supplies may become available, which will ultimately help wineries improve the efficiency and sustainability of their winemaking operation.

Research Article Source

This is hardly all the information that can be found in the research article summarized today. If you’re interested in more details about this study or the nitty gritty science of it all, please follow the links below where you can find this research article available for free (open-access).

Mierczynska, Agnieszka and Dabare, Panthihage Ruvini and Reilly, Tim and Mierczynski, Pawel and Bindon, Keren and Vasilev, Krasimir. 2023. A Novel Solution to Tartrate Instability in White Wines.

Available at SSRN: https://ssrn.com/abstract=4330933 or http://dx.doi.org/10.2139/ssrn.4330933