Oak barrels perform an important role in the maturation process of wine and spirit making. Australian company, RenewOak, has brought into commercial application a unique and sustainable process for the rejuvenation of used oak barrels.

It provides a service that economically extends the life of such barrels, or it supplies barrels that have been rejuvenated using the process at a fraction of the cost of new barrels. The technology can improve business profitability and simultaneously improve the quality of the product.

Over 2020 to 2022, the company has undertaken wine and spirit trials using the rejuvenated barrels in Australian wineries and distilleries, with favourable outcomes. Wines and spirits from the rejuvenated barrels have demonstrated improved brightness and freshness when compared to the control (an un-rejuvenated barrel of the same age) and oak influences comparable to that from a much younger barrel.

There are other ways to ‘renew’ used barrels, too, such as shaving the inside surfaces of the staves on a kind of planing machine. This necessitates dismantling the barrel and re-assembling it after shaving, which is time-consuming and expensive.

The process is completely “organic” and does not involve the use of chemicals. All materials involved are chemically inert, and no harmful residues remain in the barrel. 

With RenewOak’s method, barrels don’t have to be taken apart. An abrasive mixture is poured in through the bung-hole and the barrel is spun on a machine.

The mixture, which includes crushed rock and glass, is rumbled inside the barrel, similar to the way gemstones are polished. The barrel is then steam-cleaned.

Benefits

• Economical: substantially reduces the cost of barrel purchases (by over 30%) without impacting quality
• Risk Management: reduces the risk of contamination through use of older barrels
• Flexibility: ability to better utilise barrel inventory
• Price premiums: the rejuvenated barrels result in attractive characteristics for wine or spirit – improved brightness and freshness when compared with un-rejuvenated barrels
• Environmental: more sustainable use of a valuable natural resource.

The environmentally sustainable process, developed over the last 3 years, and the patent-protected RenewOak process has been tailored to the needs of wineries and distilleries that rely on oak for quality production.

All barrel residues, such as tartrates that are not effectively removed by pressure cleaning, and a fine layer of the oak surface are removed, leaving a clean timber finish ready to impart desired properties to the wine or spirit, or for further treatments.

The process is suitable for used red or white barrels up to 12 years old that have been kept in reasonable condition (i.e. structurally sound, well hydrated) in barrique, hogshead and puncheon barrel sizes.

Wine maturation trials undertaken by RenewOak – and testing by the Australian Wine Research Institute – have indicated that it is possible to rejuvenate an ex-red barrel (say less than 6 years old) such that the barrel can then be effectively used for white wine.

The rejuvenated barrel does not add colour or other undesirable traits to the white wine produced.

The company now has over 100 customers across the wine and spirits sector and as a key part of its marketing approach, it has undertaken numerous barrel cleaning and product maturation trials using the rejuvenated barrels. In all cases, the outcomes have been favourable.

Trials have included grape varieties such as Shiraz, Cabernet Sauvignon, Tempranillo, Pinot Grigio and Chardonnay.