The best sip off the Old Block

Age was a recurring theme at St Hallett's recent celebration of the 30th vintage of its flagship Old Block Shiraz. Age is, of course, an important factor in the provenance of the wine. It's not called Old Block for nothing. The first two vintages, in 1980 and '82, were sourced solely from the vineyard affectionately known as the Old Block, which was planted by the Lindner family in 1912, on the site where the winery is today. That's pretty ancient by any yardstick.

Then there's the winemakers. Stuart Blackwell has been chief winemaker at St Hallett from its rebirth in the late 1970s. Now, he's more like a winemaker emeritus, or style counsel. He spends a lot of his time doing promotional work, and has been replaced as hands-on winemaker by the youthful Toby Barlow, formerly winemaker at Mitchelton. Prefacing the final bracket of wines in the tasting, 2006 to 2010, Blackwell said: ''This is where Toby has taken over: the hip-hop versus the hip replacement.''

The Barossa Valley is the repository of some of the oldest vines in Australia - indeed, the world. But old vines don't in themselves guarantee great wine. The vines have to be healthy and in good order, and the wine has to be well made.

This fact was apparent to Blackwell early on. The Old Block did not always come up to par. He decided to supplement the wine with grapes from other old vineyards. Sometimes there was no Old Block at all: indeed, no Old Block grapes have been used since 1999. And, from 1984, grapes from the higher, cooler Eden Valley have been blended with those from the Barossa Valley floor to bring elegance to what might otherwise be more of a blockbuster than Blackwell wanted to produce.

Old vines can, of course, give fruit of great depth and concentration. They typically give small yields of small berries with softer tannins and concentrated flavour, and because their roots tend to be deep (especially if unirrigated), they are consistent, and can weather the years that bring extremes of drought or rain.

''We consider old vines to be 35 years and older,'' Blackwell says. ''They tend to produce shiraz that has darker-fruit flavours - blackberry, etc. The red fruit flavours tend to come from younger vines.'' Then he adds quickly: ''It's a rule that's easily thrown out, though.''

I found at St Hallett that the old vines gave wine of extra colour saturation, great palate density and complex aromas that evoke not only fruits but tar, bitumen, smoke, creosote, earth and humus, even black coffee. After oak-maturation, you can add mocha and dark chocolate to the espresso tastes and aromas.

Consider the Koch family's Willandra vineyard beside Jacob's Creek in the Rowland Flat area. First planted in 1919 by the grandfather of present owner Graeme Koch, this vineyard now covers 32 hectares. Fruit from its 1926 block is one of the mainstays of St Hallett Old Block Shiraz. It's been part of the blend every year since 1990, gradually increasing in importance in the mix. Since 2003, it's been at least 45 per cent of the blend, often much more. The second-most important grower is the Fechner family of Moculta, whose grapes are included most years.

Standing in the Willandra vineyard, I tasted two samples of 2012 shiraz that had been made from its vines. Wine one had staggering density of colour, aroma and palate - the last both in texture and flavour. There was fantastic depth of blackberry and blueberry aroma, plus tremendous richness, extract and a wealth of tannin - soft, silky tannin, nothing harsh or astringent about it, even at this tender age.

Wine two was picked on a different day, and was lighter in every way: more fragrant, with more high notes, leaner and more elegant, tighter, with good acidity, but not as rich or fleshy as wine one. But it would also be a useful component of Old Block Shiraz.

As Blackwell said: ''We've never been about creating the biggest burster of a wine, but celebrating the history and tradition of the region.'' To that end, the blend might include components from Rowland Flat, Light Pass, Kalimna, Greenock, Angaston, Seppeltsfield, Moculta, Williamstown, Springton, Tanunda and elsewhere.

Old Block has never been one of the Barossa's Betty Blockbusters. It's never aspired to that.

On the other hand, some of the blockbuster wines might not be as long-lived. Old Block has proved to have a long lifespan. In the 30-year tasting, none of the vintages were ''over the hill'': those that had faded or were past their best were from the less successful vintages, and this is a matter of the season, not the fruit-sourcing or winemaking style.

The winemaking has always emphasised freshness, and Blackwell has never been afraid to correct the acidity if need be. This is also important for longevity. Oak has been scaled back and the wine is less oaky today, although it sees a high proportion of new barrels. They were 100 per cent new in the mid-2000s but this has been backed off a little. As well, it's now 100 per cent French oak, whereas in the early days it was all American. Quantity varies widely: the 2007 was the smallest output at 700 cases; good years can produce as much as 3000 cases.

The best vintages? The 2010, to be released on July 1 at $100 a bottle, is probably the best yet. Then came, in order (on my notes) 2006, 1990, 1982, 2002, 2008, 1991, 1999, 2004, 1996, 1994, 1986, 2001, 1988, 1984, 1998, 1992, 2009, 2007, 1995, 1997, 1985, 1980, 1987, 1989. Those below par on the day were 1983, 1993, 2000, 2003 and 2005.

Complete tasting notes at huonhooke.com.

2010 St Hallett Old Block Shiraz

(20 per cent Eden Valley. 14.2 per cent alcohol; screwcap)

Deep, dense, dark-purple colour. Concentrated black fruits, dried herbs, sage, pepper and blackberry. Hints of liquorice and aniseed, but subtle. Very complex and stylish; great concentration and power; a profound and enormously impressive wine, of tremendous softness and persistence. Best drinking 2015 to 2045. 97/100.