Cleaning and Sanitizing Wine Barrels Efficiently with Ultrasound
Oak barrels for wine ageing can be efficiently cleaned and sanitized using power ultrasound. By sonication, tartrate is removed and microorganisms such as yeast (Brettanomyces, Dekkera) are killed. Additionally, wooden aroma compounds become more available when the barrels are used afterwards for wine ageing and maturation.
Ultrasonic Cleaning of Wine Barrels
High-power ultrasound shows various effects on the surface and the deeper structure of the wood. Ultrasonic (aka acoustic) cavitation wood creates locally energy-dense condions including high pressure differentials, high temperatures and high-speed liquid streaming.
These physical / sonomechanical forces lead to an intensified wetting of the barrels‘ surface, removal of residual deposits (e.g. tartrate), the disruption of microorganisms and increased oxygen transfer kinetics.
- Removal of tartrate
- Inactivation of mircroorganisms
- Activation of the wood surface
- Improved oxygen desorption
- Making aroma compounds available
Ultrasonic Wine Barrel Sanitation – Scientifically Proven Results
Scientific analysis such as microorganism count and specific surface measurements demonstrate the ultrasonic inactivation of microorganisms and the tartrate removal scientifically. It has been proven that ultrasonic barrel cleaning gives reliably reproducible results (repeatability) and is not influenced by the heterogeneity of the wood surface. Wooden barrel planks show a certain hydrophobicity, which inhibits the release of aroma compounds from the deeper wood structure. High-performance ultrasound could increase the contact angle between wood and liquid, especially at high temperatures (80◦C). Thereby, high-performance ultrasonics promotes the initial oxygen transfer capacity of the wood, since the wood is recovered as tartrate is removed and the wood is properly sanitized. The effects of intense ultrasound clean not only on upper surface, but penetrate deeper wood layers through the naturally present pores in wood.
This deep effect of sonication not only sanitizes the barrel, but also makes the aroma compound present in the wooden structure available for wine ageing and maturation.
Ultrasonic Yeast Killing
The study of Breniaux et al. (2019) also demonstrated that high-power ultrasound was able to remove 35% of the population for Brettanomyces spp., 36% of total yeast, 90% of lactic acid bacteria and 100% of acetic bacteria up to a depth 8 mm in the wood structure. With optimized operating parameters, the researchers could even improve the sonication effects further, so that the ultrasonic sanitation effect reaches a depth of 9 mm in the wood, which is also the depth to which the wine and therefore Brettanomyces yeast can penetrate.
Ultrasonic Effects on Oxygen Desorption of Oak Barrels
Ultrasonication has significant effects on the oxygen desorption capacity of wood. When sonicated and untreated oak wood were compared, the oxygen desorption rate was two times lower in the non-sonicated wood. After the high-power ultrasound treatment, the oxygen desorption was close to 10 mg/L indicating a significant increase in oxygen desorption capacity due to sonication. These oxygen desorption values of sonicated reused oak barrels are comparable to an unused oak wood, which indicates that used barrels can be ultrasonically rejuvenated and the oak structure is not negatively impacted. (cf. Breniaux et al., 2019)
High-Performance Ultrasonicators for Barrel Cleaning
Hielscher Ultrasonics is market leader for high-performance ultrasonic equipment. The operating parameters such as ultrasonic amplitude, time and water temperature contribute to the efficiency of the ultrasonic cleaning and sanitation of wine barrels. Hielscher high-power ultrasonicators are fully controllable for reliable cleaning and sanitizing effects. The UIP4000hdT equipped with a cascatrode is the most typical setup used for the efficient and rapid deep-cleaning of wooden wine barrels.
With long-time experience in design, manufacturing and distribution of ultrasonicators, Hielscher ultrasonicators are known for performance, robustness and reliability.
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Literature / References
- Breniaux, M.; Renault, P.; Meunier, F.; Ghidossi, R. (2019): Study of High Power Ultrasound for Oak Wood Barrel Regeneration: Impact on Wood Properties and Sanitation Effect. Beverages, 5, 10; 2019.
- Xusheng Li, Lei Zhang, Ziyao Peng, Yaqi Zhao, Kaiyun Wu, Nan Zhou, Yin Yan, Hosahalli S. Ramaswamy, Jianxia Sun, Weibin Bai (2020): The impact of ultrasonic treatment on blueberry wine anthocyanin color and its In-vitro anti-oxidant capacity. Food Chemistry, Volume 333, 2020.
- García Martín, J.F., Guillemet, L., Feng, C., Sun, D-W. (2013): Cell Viability and Proteins Release during Ultrasound-Assisted Yeast Lysis of Light Lees in Model Wine. Food Chemistry 2013.