There has been a long standing relationship between wine and oak.  And while it is not entirely clear how barrels actually originated as a vessel for wine, we do know that certain varieties are enhanced by the use of oak.  It provides an added dimension of aroma and flavour to the wine along with secondary nuances that stainless steel cannot.

Many of us know that the majority of wine is aged in oak barrels.  But why?  What are the advantages?  Are there any disadvantages?  Are there different kinds of oak?  Why are they different?  What flavours are added to the wine?

Around the world, winemakers use American, French or Eastern European (Hungarian and Slovenian) oak with each geographic region contributing something a little different.  French oak comes from five forests that were planting around the time of Napoleon for use in building ships.  Now that ships are no longer built from wood, the forests are used for wine barrel production.  Each of these forests, Allier, Limousin, Nevers, Trancais and Vosges produces wood with distinctive characteristics.  One such characteristic is the tightness of the wood grain, which tends to impart characteristics of vanilla, spice and butter flavours much more slowly than wood with a looser grain such as American.

Very early experiments with American oak were not very successful since the amount of influence that the barrel had on the taste of the wine was too great.  The difficulties were caused by the way the wood was prepared and the way the barrel was constructed.  As more traditional French barrel making techniques were used on ‘foreign’ oak, the results improved dramatically.

Two very significant differences between American and French barrel making techniques was the seasoning of the wood and the way the stave’s were prepared.  French barrel stave’s are air-dried for at least 24 months while American oak, which was traditionally used for whiskey barrels, was kiln-dried.  The American oak stave’s were also sawn rather than split along the grain.

French barrels are low in cellulose called tyloses, which gives the water retaining properties to barrels.  It is for this reason that French oak cannot be sawn into stave’s but need to be split along the grain of the wood.

American oak has much more tyloses and can be sawn across the grain while still retaining its watertight properties.  This is one of the main drivers of price.  Splitting is slow and requires expensive expertise, while cutting is cheaper and simpler this makes American oak barrels cheaper to produce.

Oak’s primary influence is to accentuate aromas that center on the spice rack, with clove, cinnamon, nutmeg, vanilla and “allspice” being common aromas derived from the time in oak.  You are often able to taste and smell these characteristics with vanilla being the easiest to discern.

On the palate, oak’s influence turns towards the rich flavours of caramel, coconut, vanilla, cinnamon, clove, smoke, tea, mocha, toffee and butter.  These flavours enter the wine as it ages in the barrels, with the newer barrels passing more flavour than older 2-3 year old barrels.  As significant as barrel flavour is, the exposure of the wine to small amounts of air that seeps through the pores of the wood is also important as the oxygen softens the wine and changes it greatly.  If oxygen can seep in to the barrel, wine can also evaporate out. For this reason, barrels must be kept topped up or risk oxidation and spoilage.

Constructing a barrel is as complex as growing grapes and making the wine.  But before construction can begin, the cut/split oak stave’s must dry out and season. This allows some important chemical modifications to occur.  Tannins are reduced, as are some of the bitter tasting compounds.  At the same time there is an increase in some aromatic compounds. Drying stave’s in ovens is quicker and cheaper however the chemical changes do not occur. The consequence is that the oak has fewer aromatic properties and more bitter components ready to leach into the wine.  Poorly seasoned oak can lead to off odours.

Toasting involves heating the barrels over a fire, so that they can be bent and shaped.  A charring of the wood occurs on the inside and the level of toasting will determine how much of a toasty flavour will be imparted in the wine.  When used appropriately, these can have a significant beneficial effect on the wine’s flavour.

To save time and money, various techniques have been developed to extend the use of a barrel or to gain the benefits of oak aging without actually going to the time or expense of the traditional methods.

One method involves shaving the inside of used barrels and inserting new thin inner stave’s that have been toasted. Another procedure is to use oak shavings in a large ‘tea bag’ that is placed inside stainless steel tanks of wine.

However, none of these cost saving techniques has been able to achieve the results of traditional barrel production and the aging of wine.

Sourced from low cropped vines at the Summa Quies Vineyard on the Naramata Bench, the 2008 Howling Bluff Sin Cera  is a Meritage blend of Merlot, Cabernet Franc and Malbec.  This outstanding BC red offers a full bodied structure with buckets of juicy ripe black plum, cassis, black cherry, licorice, vanilla, black olive, tobacco and roasted coffee aromas and flavours with a hint of toasty vanilla oak on the intense finish.  A thick, concentrated yet velvety texture with soft acidity and full, firm tannins, it is the perfect partner with a grilled steak or mixed grill.  In fact, it needs food.  Ready to drink now and over the next 5-8 years.

An outstanding bargain in a Chateauneuf-du-Pape, 2009 Domaine Barville Châteauneuf-du-Pape is a huge wine for the price.  Loaded with fragrant aromas of sweet raspberry, kirsch, strawberries, spice box, leather and smoke, the palate is well structured with its rich flavours of black and red fruits, spice, garrigue, soft acidity and firm tannins.  Fantastic to enjoy now for the sheer power of it but will reward with 8-10 years of further cellaring.