WHEN A BARREL BECOMES AN INVISIBLE RISK
Brettanomyces, Biofilms and Contamination: The Hidden Cost of Contaminated Barrels
A barrel is much more than a simple container.
It is a maturation tool that plays a key role in the development of the wine’s aromatic profile, structure, and evolution over time. However, the very nature of wood—a living, porous material—also makes the barrel one of the most microbiologically vulnerable elements in the winemaking process.
Every year, wineries face problems related to barrel contamination, often without realizing it until sensory defects have already developed and become irreversible.
Among the main culprits is Brettanomyces bruxellensis, a spoilage yeast capable of colonizing wood and proliferating within the barrel’s microscopic pores and crevices.
The consequences are well known to winemakers: volatile phenols, accompanied by aromas of leather, sweaty horse, barnyard, medicinal notes, or adhesive bandages, can compromise the aromatic profile of wines intended even for the most premium market segments.
However, Brettanomyces is not the only concern.
Microbial biofilms composed of yeasts, molds, and bacteria can develop inside barrels, becoming increasingly difficult to remove over time using conventional cleaning procedures.
Why the problem gets worse over time
A new barrique can cost several hundred euros.
For this reason, it is normally used for multiple production cycles.
With each harvest, the wine penetrates the wood fibres together with organic residues and microorganisms.
Over the years, the likelihood increases that these can find shelter within the internal microporosities of the wood, where conventional surface treatments can only reach them partially.
It is precisely in these areas that cross-contamination between one production batch and the next can occur.
The limitations of traditional systems
Historically, barrel sanitation has mainly relied on:
- hot water;
- steam;
- sulfur dioxide (SO₂);
- specific chemical products.
These systems remain essential and represent a well-established practice in the industry.
However, each method presents operational limitations:
- treatment times;
- energy consumption;
- management of chemical products;
- limited effectiveness in the deeper pores of the wood;
- risk of recontamination.
In recent years, research has therefore started to evaluate complementary technologies capable of improving microbiological control without compromising the quality of the barrique.
The contribution of Ozone
Thanks to its high oxidizing power, ozone is now one of the most studied technologies for barrel sanitation.
When produced using equipment specifically designed for this application and applied according to validated protocols, it can significantly contribute to reducing the microbiological load present on the internal surface of barriques.
Ozone is generated directly from atmospheric oxygen and, once its action is complete, it naturally reverts back to oxygen, leaving no chemical residues.
Applications can be divided into: gaseous ozone treatment and ozone-enriched water treatment. Both applications follow specific protocols.
Not all systems are the same
One of the most common mistakes is considering any ozone generator suitable for barrique sanitation.
In reality, ozone concentration, humidity, contact time, gas flow rate, and distribution method determine completely different results.
For this reason, the technology must be specifically designed for the wine industry and for the processes already in place.
The effectiveness of ozone depends much more on the quality of the application than on the simple production of the gas itself.
Preserving the value of the barrique
Proper microbiological management does not only mean reducing the risk of contamination.
It also means:
- preserving the economic value of the barrels;
- extending their useful life;
- reducing production waste;
- increasing the qualitative consistency and repeatability of winemaking processes;
- improving the safety of the entire production process.
For a winery, protecting a barrique also means protecting the wine that it will hold.
A technical insight, not a commercial one
The objective today is not to replace the established practices of the winery, but to integrate technologies that allow increasingly effective management of complex microbiological challenges.
Among these, the management of contamination in barriques represents one of the most important challenges for modern oenology.
PROTEA
For over twenty years, ProTeA S.r.l. has been operating in the research, design, and production of professional systems based on ozone technology, developing solutions dedicated to the sanitation of environments, equipment, water, and surfaces across numerous industrial sectors.
The experience gained through collaborations with leading companies in the food, healthcare, industrial, and oenological sectors has enabled the company to develop an approach based on solid technical and scientific foundations, as well as on the design of application-specific solutions for each operational context.
Each system is developed following a preliminary analysis of the customer’s requirements and the characteristics of the application environment, since ozone effectiveness depends on the correct management of parameters such as concentration, contact time, humidity, temperature, and the volumes to be treated.
For this reason, ProTeA does not offer standardized solutions, but rather develops systems specifically engineered to ensure reliable, repeatable, and safe performance over time.
Research and development are at the heart of the company’s activities: all systems are designed and manufactured in Italy with the aim of combining technological innovation, environmental sustainability, and microbiological safety, providing solutions that are also applied in the wine industry, where contamination control plays a crucial role in ensuring the quality of the final product.
