A new version of a blended whisky has been released under the soubriquet of 'Spanish oak'. The  special edition is "exposed to first-fill Spanish oak casks for longer than usual". 

What is Spanish oak? It is actually Quercus Falcata, or "red oak", native to south-eastern America, where the light-red wood being hard and coarse-grained is used for lumber, furniture and flooring  - and is not used for whisky casks as they would leak excessively - therefore a misleading title on a whisky bottle.

Casks for the Sherry industry are made from  either domestically grown or imported Quercus Alba (white oak) commonly known as American Oak, being the same oak used for the Bourbon industry.  The cellular structure of white oak contains tyloses, a bubble-like cell structure that bulge through into the cavities of the xylem - the tube-like moisture conducting cells - blocking water movement. Thus tyloses in white oak makes the wood watertight, which is why it is used for casks rather than Spanish oak which lacks them. There is a simple test you can do to demonstrate this: take a white oak and red oak twig  1/2" (or 1cm) in diameter  3" (or 8cm) long and insert each snugly in to  their own piece of plastic tubing. Attach the other end of the tube to a tap and slowly turn on the water. Drops of water will appear at the end ot the red oak twig, but not the white oak. Instead of water, this can be replicated with gas  and  a flame lit at the end of the twig!

Even the term sherry 'wood' or sherry 'cask' is open to considerable confusion - and deceit. It should mean casks that have had Sherry maturing in them for several years. But in reality it is often sufficient for the  casks to have been merely coopered in the Sherry region. The title can even be obtained by the simple inclusion of a few bottles of the sweetest sherry rolling about inside newly made casks for those eager to use the sought after title along with a little E150. Once we were hoodwinked by buying such casks at a significant premium over new American  oak casks which is in reality what they really are. We sent them back.

Spanish oak, Sherry casks and sherry wood are at best misleading terms, often mischievously  exploited. Beware! Look out for the real deal.

Tylose