Winemaker and writer Paul Le Lacheur examines the benefits of sonication as an effective maceration tool.

Ultrasonics, or sonification, refers to the application of high frequency soundwaves to macerating or fermenting wines and/or musts.

“Oh,” I hear you mutter under your breath, “our humble scribe has lost it again! First he talked about playing orchestral and classical music to vines, now he’s dog whistling about soundwaves improving wine quality”. Although a relatively new idea however, it’s certainly not in the realm of fantasy.

Recently (around 2019), Ultrawine Perseo has developed the latest and most innovative eco – friendly system yet devised. Designers of this technology, Agrovin, are revolutionising the oenology sector by applying high power/low frequency ultrasound to grapes and macerating musts. It’s a notable extraction technique, without increasing temperatures or pressure. Results have proven the technique is efficient in the extraction of phenolic and aromatic compounds. This helps in alleviating the effects of climate change during the late grape ripening phase, but it also has a big impact on fermenting wines, must and where maceration times are critical.

Ultrasonics optimises winemaking processes by reducing maceration times by up to 50% and achieves energy savings of up to 15% (Agrovin research 2020). Development of the system was made possible because of the collaboration between agro- chemistry and food technology reseacrhers at the University of the UMA (Uni of Marcia 2012 – 2019) and Agrovin. In addition, it has the approval of the OIV to use ultrasound technology as an oenological practice. Ther system has obtained an international patent and has been installed and large wineries and large warehouses all around the world. In 2019, it was approved at the World Congress in Geneva by Resolution 2019/934. One of the great advantages of the system is it allow cold extraction of grape compounds through ultrasound.

The system uses a physical process called ultrasonic cavitation. It applies high-power ultrasound to the crushed paste, producing cavitation. This treatment results in the surrounding environment producing microbubbles that tend to collide with each other and release energy. This aggressive collision of the bubbles, together with the associated implosion process, wears on the skin tissue, thereby facilitating release of phenolic compounds and aromatic precursors. This advantages larger wineries because any reduction in the time devoted to maceration results in increased production capacity.

However, even small wineries can benefit from quick maceration in compressed vintages where all the fruit seems to ripen at once!

Furthering this research, there more detailed studies on the possible synergy in combining ultrasound waves with the use of oenological enzymes to extract phenolic compounds. Average maceration time in the research was seven days, with the two ‘control’ samples macerating for three and seven days respectively. These control samples were segmented as  a means of establishing a ‘statistically significant’ set of data, capable of objective interrogation.

The use of enzymes alone hardly produced changes in colour and phenolic content compared to the control. In this sense it was reported that there was a low effect of maceration enzymes when used during the vinification of grapes with an advanced degree of ripening.  (Bautista-Orin et al. 2017). This was seen as possibly due to the greater natural degradation of the grape structure with ripening.

Chromatic characteristics of the wine. as well as its content of total phenols, anthocyanins and tannins improved dramatically with sonication of the grapes, compared to the control. This was in the range of 33%-34% increase in the total purple anthocyanic pigments present post sonication.

Reducing maceration times

The tests also showed the Ultrawine Perseo (compared to the traditional maceration method) system reduces maceration times greatly, as discussed earlier. Better news follows. The stated 15% energy savings were found to result from lower consumption of components and the avoidance of the use of temperature for extraction.

The enzyme treatments to which I refer are: Ennozrm LUX, a highly concentrated pectolytic enzyme, together with additions to the crushed and destemmed must of were Ultrawine Perseo.  Measurements were taken of alcohol, pH, total acidity and volatile acidity. Total anthocyanins were included as were total polyphenolic index and methylcellulose precipitable tannins. High pressure liquid chromatography (HPLC) was also used. Tannins present in the studied wine and their composition was determined using the phloroglucinolysis method volatile acidity was detected at very low levels. The results showed that sonification of the grapes produced significantly higher colour intensity, total anthocyanin content and tannin levels. Other important outcomes were lower values for galoylation, indicating a much lower extraction of tannins from the seeds. Sonification of the grapes led to an improvement in chromatic characteristics, especially those from riper (14 Be) grapes.

Sonification had now been shown to be a superior technique than merely adding pectolytic enzymes, especially c\in terms of colour and phenolic content. However, the combination of Sonication and adding pectolytic enzymes produced a marked synergistic effect. Researchers universally commented that sonication was very effective in reducing maceration times by around 50%.

High power ultrasound systems have also been found useful in reducing the alcohol content in red wines (Martinez et al.). The conclusions reached at the end of this study showed promise in application in order to favour extraction of grape phenolic compounds, even when phenolic maturity was not complete.  Increased polysacharide extraction was also favoured in the results from red wine.

Mean particle size was found to significantly decrease post sonication treatments. The issue here is there are broadly two tannin types, namely Hydrolysable and Condensed, also known as anthocyanidins. The later type are more or less complex polymers of Flavan 3-ols or Catechins, which are the main contributors to the perception of astringency.  However, the good news is they also deepen colour from red pigments to purple ones, stabilising the colour as these positive changes occur.  What follows is a process of polymerisation and condensing with anthocyanins, then combining with proteins. Sonication facilitates these desirable sensory characteristics (Avizcati et al 2016).

In summary, sonication is eco-friendly, saves production time, money and physical space resource, making it an attractive maceration tool.

This article was originally published in the March 2025 issue of the Australian & New Zealand Grapegrower & Winemaker. To find out more about our monthly magazine, or to subscribe, click here!

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