Consistently improving the quality and reputation of Australian Cabernet

<b>Consistently improving the quality and reputation of Australian Cabernet</b>

Name: Rob Mann
Professional experience: Cape Mentelle senior winemaker and Cabernet aficionado.

By Robert Mann
Senior Winemaker
Cape Mentelle Vineyards
Margaret River, Western Australia

Cabernet Sauvignon has a long and celebrated history in the world of wine. In Australia, it has been planted since the early 1800s when early pioneers toiled with the vagaries of virgin soils and micro-climates in a young nation primarily fuelled on spirits and fortified wines along with the customary beer. The sophisticated members of society would have found great pleasure in the Clarets imported from France and it would not be long until the varieties comprising the great wines of Bordeaux were imported and established in small pockets all over Australia.

Author A. Despeissis, in his text The Handbook of Horticulture and Viticulture of Western Australia published in 1903, summarises the properties of Cabernet Sauvignon by saying, 'One of the choicest red varieties of France, making high class Medoc wine. Merits: of the highest as to quality, but giving a small crop. Flesh; hard and juicy, with peculiar flavour, which is common to Cabernets. Best suited to rich loamy soil mixed with gravel. Suitable for the cooler districts. It forms in the Bordeaux districts of France, the foundation of the first growths of the world-renowned Chateau Lafite, Chateau Margaux, Chateau Latour, etc. where it is blended with Malbec, Merlot and Petit Verdot. Blended with Malbec and Shiraz, and other good sorts, it makes a most suitable wine for either local or the export market'.

I do not think I could summarise the merits of the variety better, even after more than 100 years. As with most varieties, a narrow band of variables need to be aligned if great wines are to be produced consistently. These variables constitute what we now commonly refer to as terroir, for which Australia has two definitive champions being Coonawarra and Margaret River with many other excellent examples from other regions. It has taken many generations to understand Cabernet Sauvignon's synergy with these particular regions. We are now at a point in Australia's history with the variety where we can either continue on the same path of producing good quality, reliable wines or invest in achieving world-wide recognition.

We can learn much from the experiences of other countries. The vineyards of the Napa Valley have historically produced high quality Cabernets but it was not until the late 1980s that phylloxera again found an affinity with a widely used rootstock and a large replanting effort followed. A significant investment was required to improve on the vineyards of old and aim for quality over quantity. This resulted in a diverse range of clonal material being imported, significant work on the properties of rootstocks and the ability of a Cabernet scion on appropriate rootstock to produce wines of higher colour, lower phenolics, earlier ripening and ultimately better wine quality. The row orientation, planting density and canopy management were in many cases revolutionised with the ultimate result being a competitor to Australian Cabernet.

Western Australia has been growing Cabernet Sauvignon for well over a century. In the mid 1960s, the now well-known Margaret River and Great Southern regions were established on the potential to produce Cabernet Sauvignon wines of a high standard. Great success has followed with the variety but this has been based on one recognised clone, 126, and a selection of vines from the Houghton vineyard in the Swan Valley, commonly referred to as the Houghton clone. To this day, Western Australia's Cabernet harvest would almost entirely comprise these two clones. Given a strong history and tight quarantine laws there has not been much push for improved planting material. The industry has had some famous triumphs but how would new clonal material fare in sub-regions so perfectly suited to the variety?

The story in Eastern Australia is a lot less restrictive in terms of access to clonal material. Indeed, much work has historically been carried out in identifying and selecting a diverse range of Cabernet clones but the selection criteria rarely involved ultimate wine quality, but rather, measures of yield, consistency, and vine management. The result is many clones planted in many regions in large volumes that ultimately do not consistently produce wines of greatness.

The last 10-15 years has seen a great deal of work on importing clonal material into Australia but this has concentrated more so on varieties other than Cabernet and perhaps the greatest resource for improving the potential of this variety in Australia will ultimately lie here. In addition to clonal material, the importation of rootstocks and the matching of rootstocks to micro-climates, soils and scions hold great potential in improving wine quality. In much of Southern and Western Australia most would consider planting on rootstock an added expense and a time delay in establishing a vineyard but the potential rewards for getting the match right has to be worth the cost. Producers can achieve darker wines with softer tannins, richer and riper fruit characters and with the added benefit of lower potential alcohols and higher natural acidity, which most would agree would be desirable.

Water and environmental stress have a major negative impact on the potential wine quality of a Cabernet vine. Stress in Cabernet is in my opinion the main reason the wines express menthol and eucalypt characters typical of Australian wines. This trait is not confined to land historically growing gum trees. In the pursuit of riper, thicker, more concentrated wines around the globe, the result has been grapes hanging longer on vines to the point the vine can no longer support the vitality of the fruit. The resultant stress may be the reason wines from Bordeaux, Chile and California can often express a eucalyptus character without ever being exposed to gum trees or a source of eucalyptus oil.

Within an established vineyard the vigneron has many decisions that can influence the potential wine quality. Cabernet Sauvignon is a variety that does not tolerate stress at all well and this has to be avoided if a well-balanced wine is to be achieved. When I studied winemaking in South Australia, much of the research was directed at establishing the correct amount of stress a vine needed to produce small berries of highly concentrated, intensely coloured wines. The extreme in practice was red varieties with moderate unreliable crops of small bunches, with small berries on a large number of short stunted shoots. The results when made into wine were typically green, tannic, hard and poorly coloured without balance or refinement. We should not be aiming for small berry size in red varieties, but rather, an ideal berry size, which is not too big or too small.

Vine balance plays a key role in getting this relationship right and if great wines are to be consistently produced from Cabernet, hard cane-pruning to minimal bud numbers combined with shoot-thinning is the easiest formula in which to achieve the goal. The right bud numbers will vary from site to site and only experience will yield the greatest wine quality for the vigneron. Given the many issues in Australia relating to water quality and quantity, the efficient use of this critical resource in the maintenance of vine health with respect to maximising wine quality needs to be of strong consideration if a sustainable industry is to be maintained and developed.

Australia is blessed with many diverse viticultural regions, of which some have great potential for world-class Cabernet wines. We have the requisite passion to produce wines of greatness and longevity. We are rightly proud of the wines we have produced in their reliability and drinkability but if we are to compete on the world stage with wines based around Cabernet Sauvignon, much more focus is needed. A simplified approach of establishing the right planting material, matched to the soil and climate, combined with increased management inputs, with respect to pruning, canopy and water management, will significantly improve our wines.

With the viticultural resource strengthened, the pool of potential wine quality will be significantly stronger. In producing a desirable Cabernet wine that has wide international appeal, the strength of Australia's regional identity will become even more important. Australian producers cannot afford to be categorised as producing one-dimensional Australian styles of Cabernet. It is in our diversity of regions and sub-regions that produce unique expressions of Cabernet that will generate consumer interest and loyalty. A great deal of investment is still required in many of the fundamentals if we are to grow our reputation internationally and perhaps reinforce my belief that 'Cabernet Sauvignon is the only grape tolerated in heaven'.

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