With too much wine already in stock, Australia was hoping for a smaller harvest this year but the 2006 crop is only slightly down on last year's record levels. In the first of just-drinks.com's southern hemisphere harvest reports, Penny Boothman assesses Australia's 2006 vintage.

A cool spring and early summer with bursts of intense heat in mid-summer characterised the 2005/2006 growing season, with premature autumn rains threatening the end of an early harvest in many areas.

Early figures may have brought false hope to the over-stocked Australian wine industry, with the suggestion that yields would be around 7% down on last year, but more recent data shows a fall of just 1% in production to 1.9m tonnes, just below the record 1.96m tonnes of 2005. Once again, this year at least 2% to 3% of Australia's total grape crop is likely to remain unpicked as fruit prices are uneconomically low at just A$200/tonne in some regions.

The productive Murray Valley and Riverland regions reported a drop in total grape production of 5% and 10% respectively, but in the inland Riverina region, home to Casella Wines, tonnage increased again by 20%. White grape varieties, which were in short supply last year, actually grew by 4% in 2006, while red grape production fell 5%, now making up 54% of total production.

Spring rains were good in most regions, and encouraged steady growth for the early part of the season. Showers in November and December increased disease pressure in some areas, but reports indicate that the season has been relatively disease-free overall. However, a different problem was encountered by growers in most regions in January when temperatures soared above 40º C on several occasions.

Many wineries in the Adelaide Hills were badly affected by spring frosts, which reduced the total intake for some by as much as a quarter. Later in the season, a cool and very rainy April also impacted on red and white grapes in this later-ripening area with the threat of bunch rot and mildews. Red fruit in the Coonawarra was similarly threatened due to early autumn rains.

Western Australia as a whole experienced the coolest December and January on record, with temperatures hovering in the low 20s for days at a time. Consequently when tropical cyclones brought rains in April, much of the red fruit had still only reached around 10º on the Baumé scale which is frequently used to measure sugar concentration. One degree Baumé is equivalent to 1.8% sugar. A typical red wine grape such as Shiraz is generally harvested when the grapes are between 12º and 14º Baumé. The Western Australian white wines, however, were less seriously affected.

Winter and spring rainfall was also well above average in the Barossa and Eden Valleys resulting in a low water stress season for the region. A cool start to the 2005/2006 growing season meant that budburst, flowering and veraison occurred around a week later than normal here. However, brief rains in late-February, followed by another period of warm weather, led to very rapid ripening and a quick onset for the Barossa harvest. The ripening rate then dropped off rapidly from late-March onwards, with 60mm of rain falling on 27 and 28 March, and a sudden fall in day and night temperatures, which slowed the pace of red grape maturation almost to a standstill. Conditions in the Barossa were favourable for very good colour and tannin development, and good acid and pH levels. Yield levels were average in most varieties, except for Shiraz which was slightly below average.

Langhorne Creek producers also reported an early start to the vintage, with one grower picking their first Shiraz on 26 February, and rainfall at the end of vintage after most fruit had been picked. Yield levels here were average overall.

Tasmania brought in one of the earliest vintages on record. The island state escaped the extreme January heat that most other regions saw, but a warm spring with good rains accelerated the growing season from the start. A very good quality year for aromatic whites is expected, with reds slightly lighter than 2005. Cropping levels are said to be average to good.

The quality of the 2006 harvest overall has been rated as good to excellent, though not outstanding, in the country as a whole. A report from Peter Bailey, senior analyst at the Australian Wine and Brandy Corporation, predicted: "The quality of the harvest will also further enhance Australia's reputation for producing premium-quality wines."