Why do winemakers use oak?
An oaked wine (otherwise known as wooded wine) can be an acquired taste for some, but many people really enjoy the flavours imparted by an oak barrel from the outset. Oak barrel fermentation adds a range of flavours to wine including vanilla, cloves, butter, popcorn, toast, spice and char. Oak also provides complexity to a wine’s aroma and taste.
The porous nature of oak allows for the right amount of oxygenation and evaporation for wine to ferment. It is this gradual introduction of oxygen that results in a smoother rounder finished product. Oak is the ideal timber for a wine barrel because it is strong and can be bent into barrel staves. Oak has a neutral wood smell and is high in tannins. Tannins allow red wines to age at an ideal rate and the oaky walls of the barrel provide gradual extraction of wood flavours into the wine as fermentation occurs. The use of oak barrels is a long-held winemaking tradition throughout the world and remains popular to this day. Even in modern wineries where production is predominantly in stainless-steel tanks, oak chips contained in fabric bags or cut barrel staves might be used to impart oaky flavours. Many winemakers, of course, believe there is no substitute for the real thing, when the budget allows for it.
Generally, Margaret River winemakers use either French oak (Quercus robur) French white oak (Quercus petrea) or American white oak (Quercus alba). Barrels from other parts of the world, including Asian and Eastern European regions, are also used. Experienced winemakers might choose to employ a combination of oaks (depending on the grape varieties used) and to expose them to those various oaks for a specific amount of time. This level of winemaking requires a high degree of discernment and for this reason oak plays a very important part in creating wines of distinction. Fermenting in oak is a technique that our local Margaret River winemakers excel at and after years of experimentation carefully constructed oak regimes are without doubt crucial elements of some of our favourite local vintages.
Each oak variety has unique characters which a winemaker will select for. French oak is much tighter grained than American oak and as a result of this imparts more subtle savoury and spicy flavours. French oak is has firmer, but silkier, tannins while American oak delivers a more intense oak flavour, sweeter coconut and vanillin characters and a more robust mid-palate. Experts in barrel production understand that even different microclimates can affect the qualities of an oak barrel despite being the exact same variety. French oaks are known to have noticeable variations, depending on which region they are from, which means growing and marketing premium oak is a serious business and a matter of great pride. Many vineyards use barrels from a variety of regions across the globe, carefully matching the grape varieties with a barrel type and age.
An oak barrel is the ideal environment for encouraging metabolic change, such as malolactic fermentation (which makes wine taste and feel creamier on the palate). Malolactic fermentation creates what is known as secondary aromas. This is in contrast to primary aromas which come from the grape variety itself.
How are oak barrels made?
Oak staves (barrel pieces) are seasoned before they are fashioned into barrels. Natural seasoning of staves is a slow process usually taking a few years to complete. Kiln drying staves is another option which is faster but it doesn’t soften tannin in wine as much and therefore is not as ideal.
The average life of a barrel in use is five years, however after this time a specialist in making wine barrels (known as a cooper) can shave each stave to reveal fresh oak. The staves are then toasted, and sometimes charred with fire, before being reused. New barrels release bolder flavours, compared to previously used ones, and while bold flavours may be desirable, used barrels are frequently selected where more subtle or delicate flavours and aromas are preferred. Sophisticated winemakers refine their vintages by carefully choosing a mixture of old and new oak to achieve the desired amount of tannin and oak flavours.
Standard oak barrels generally range in price from $900 to $2000, however larger or specialised barrels may fetch a higher price. Oak trees can take hundreds of years to reach an age where they can be felled for barrel production. Barrels must travel by sea to get to Australia and when we take that into consideration, the price of barrels is quite reasonable. Quality oak barrels are highly sought after by Margaret River’s winemakers. Once acquired, these barrels consistently weave their magic, assisted by time-honoured winemaking traditions, to create spectacular local vintages.
How many years does wine stay in the barrel?
It can take anything from months to years to mature wine in oak barrels. Many Cabernet Sauvignons in the Margaret River region have spent up to two years in a barrel before they are released. So next time you are tasting a fabulous oaked Margaret River wine, even if it’s still not really your cup of tea (yet), consider the role an oak tree has played in creating the flavours and aromas. Three cheers for the majestic oak tree.
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