Novel wine barrel cleaning

Celia Johnson

Australian-based Cavitus, a leading developer of hardware systems solu­tions using high power ultrasonic (HPU) technology specifically for food and beverage applications, has designed a wine barrel cleaning and disinfection system that eliminates harmful bacteria such as Bret­tanomyces dekerra (Brett) from both maturing wine and oak barrels, and reduces the premature disposal of wine barrels due to damage caused by con­ventional cleaning methods.

According to Cavitus, HPU technol­ogy has been around for decades but its potential is not well known in the food and beverage industry.

“We’ve had to go into the wine indus­try and educate global winemakers about the effects HPU can have for bar­rel washing and disinfection in terms of the increase in performance compared with what they have conventionally used for over 50 years, because many are unfamiliar with the technology,” Cavitus chief executive officer Ned Strong said.

“However, it has only been in the last ten years that the price of the equip­ment needed to generate this high-power output of ultrasound has come down to a point where it is accessible for certain applications.”

Applications of the HPU technology include emulsification, de-foaming, extraction and fermentation manage­ment, but it is HPU’s use as a cleaning and disinfection agent that Cavitus believes will bring substantial financial benefit to the wine industry.

How it works

HPU technology converts kilowatts of electrical energy into sound energy, which is then transmitted through liq­uid, whereas conventional, low-energy ultrasonic devices only convert small amounts of electrical energy into sound energy.

The sound energy causes the expan­sion and contraction of micro-bubbles of dis­solved gases until they cavitate, imploding under extreme pressures of 2000psi and tem­peratures of 5000°C, releasing huge shear waves that can be harnessed to improve effi­ciency and product quality in liquid-phase industrial processes.

The effect on wine barrel washing and dis­infecting is to clean the titrates and other detritus build-up from the inside of the bar­rels, as well as to kill micro-organisms on the internal surfaces and in the pores of the oak wood simultaneously and uniformly.

This system, which involves filling barrels to the brim with water as this is the only way to transmit ultrasound through it, results in better uniformity of cleaning and disinfecting compared with conventional spray methods.

Toast and taint

The most common barrel cleaning method used by wine processors is a high-pressure, hot-water wash, which can negatively impact on product quality and cause large amounts of waste.

This conventional method can also lead to the build-up of dirt in the barrel, affecting the synergy between the wine and wood surface required for maturing.

“High pressure tends to destroy the toast on the inside of the barrels, which is essential for transferring oak flavourings into the wine and allowing it to mature,” Strong said.

“Destroying the toast also accelerates the decline of the barrel’s lifespan, meaning pro­ducers may need to replace the barrels soon­er than expected, adding an unnecessary expense to the company.

“We did a study over several years of over one hundred barrels from different wineries in South Australia that had been continuously cleaned using conventional methods.

“When we popped the head staves off, there were residual particles and detritus left behind,” Strong continued.

“Yet that was the barrel they were going to pour fresh red wine into to try and age it.”

Micro-organisms, including Brett, that thrive in humid, warm, sugar-rich environ­ments, get trapped behind the residual dirt in the barrels and are not regularly removed with standard cleaning.

The chemicals excreted by these micro-organisms can taint the wine and give it an unpleasant taste and smell.

Financial incentive Strong commented that in the last five to six years there have been cases of small winer­ies with good brand reputations throwing out an entire year’s production of Cabernet Sauvi­gnon because of contamination, resulting in devastating financial effects.

This application of HPU technology, yet to be implemented in wineries, is anticipated to be rolled out in 2008.

Cavitus is confident that adoption of the technology will be widespread as return on investment appears strong.

“Although we estimate losses of hundreds of millions annually to the Australian wine industry, some well regarded commentators in the industry say the numbers are very con­servative and that it is closer to the USD$1 billion mark,” Strong said.

“Uptake of the technology will have a large financial impact on companies.”

In an industry in which companies constantly seek innovations to strengthen their positions in the market, Cavitus’ system has the potential to give winemakers a valuable competitive edge.

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