The well-known impact of oak barrels on the production cost of wines may be blamed on several factors.

Firstly the cost of the wood as raw material, the time required before the wood may be used and the time consuming labour during the composition and treatment of the barrels. Secondly the under-utilisation of the barrels’ wood volume, seeing that only a few millimetres of the wood components on the inside of the dowels are extracted. The use of barrels as second or third fill barrels does not make a big difference. Thirdly the apparent inability of cooperages to find a positive application for the unused wood volumes of used barrels.

Last year the Australian Co-operative Research Centre for Viticulture (CRCV) and Wine Industry Suppliers Association (WISA) held a workshop about innovation in oak flavourants and tannins. The following issues were identified as being the most important:

  • The need for standards in the descriptive terminology of oak products.
  • The willingness of wine cellars and wood suppliers to accept new technology.
  • The impact of used barrels and alternative oak products on the environment.
  • Problems experienced during the transport, handling and storage of barrels.
  • The inadequate application of existing research and development information (Corsey, 2006).

The recycling of unused oak from used barrels is an innovative development initiated by the Australian body Ausvat. The first investigation took place seven years ago in South Australia and eventually resulted in a patented process that occurs in different stages:

  • Used barrels are deconstructed by several wine cellars and the individual dowels transported in crates to the Ausvat plant. Particulars such as oak type, cooperage, barrel age and sanitation process accompany the consignment and the wood from different cellars is kept away from each other.
  • The part of the dowels penetrated by wine, is removed from the remainder of the dowels by means of a sawing process. This waste product is taken to a garbage dump away from the premises.
  • Subsequently the remainder of the dowels not influenced by wine is chopped into two battens and specified as being either inside or outside battens. These battens are shaved on both sides to expose the grain and cell structure of the wood. Possible areas of contamination, such as the ends of the battens, are also removed.
  • The subsequent toasting process is preceded by a process whereby the battens that are still in the bent shape of barrels are placed on conveyor belts for toasting, using pressure and far infra red heating (FIR) to bend the battens into shape. FIR is also used to obtain various toasting levels and the heating also results in the sterilisation and homogenising of the wood.
  • After toasting of the dowels they are stacked in bundles of 60, which is the equivalent of 8 square metres of wood surface. After leaving it for a few days to stabilise, it is finally packaged in plastic bags and may be stored for up to 6 months before being used.
  • By recycling the dowels of used barrels access to an enormous source of unused wood is gained, thereby ensuring the more effective utilisation of the wood. Unlike the normal 2.1 square metres of wood surface of a 225 litre barrel, the available wood surface of the same wood volume is increased to 8 square metres. Environmental benefits are the clean oak shavings deriving from the process which may be used to make compost, which could be especially beneficial to organically grown grapes.

Well-known Australian wine cellars such as Penfolds, Rosemount, Lindemans, Wynns, Great Western and Devils Liar are using it. French cooperages are also interested in the process and with the French having recently allowed the use of alternative wood products for vinification, the recycling of the wood from used barrels may be welcomed there too (Warren, 2006).

References: Corsey, L. 2006. Wine Industry Journal 21(5): 38 – 39.
Warren, P. 2006. Australian & New Zealand Grapegrower & Winemaker July 2006: 61 – 62.

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