The Landscape of Langhorne Creek and its Vineyards
The Location, Vineyards and a Brief History
The Langhorne Creek wine district borders Lake Alexandrina and vines now cover about 6000 hectares with most of this planted in the last dozen years. The Murray River flows into Lake Alexandrina on its way to the sea, and is a large body of shallow water that has ponded behind high coastal dunes that impede the flow of water into the Southern ocean. Except in times of drought when the ocean outlet of the Murray River may close there is an exchange of sea water from the ocean into the lake.
Langhorne Creek is very flat with the occasional metre or so roll in the landscape. It is the flat land and fertile, alluvial soils that makes the region so attractive to large scale mechanised viticulture. Plus there is evenness of the vintages and a low risk of crop failure, features that are very attractive to any primary producer. Even with these advantages and the knowledge that good and at times great wines had come from the region it was not until the export boom began in the 1990's that vineyards expanded rapidly.
This is surprising as it is not far from the old viticultural regions of McLaren Vale and Barossa Valley. About 15 kilometres north and to the east of Langhorne Creek, vineyards are planted beside the Murray River and plantings follow this river for thousands of kilometres back along its path to as far east as Rutherglen bordering the river in north eastern Victoria. These vineyard plantings began with the opening of irrigation schemes in the 1890's.
It would seem that Langhorne Creek was simply overlooked despite the very desirable features of the evenness of fruit quality and the low cost of production. About 200 hectares of vines had been planted by the mid 1980's.
The first vines were planted at Langhorne Creek by the Potts family on their property Bleasdale which was purchased in 1850. It is believed they were selling grapes to Hardys by the mid 1860's. It is likely that other small plots of vines were planted as this was commonly done as new agricultural regions opened up. One of these other growers was Edward Hector who was known to be harvesting grapes in 1869. The oldest existing vines are on the Metala vineyard and were planted in 1890 (Beeston says 1892). Production was never large with only one winery Bleasdale surviving the many ups and downs into the modern era.
Saltrams was a supporter of the area and developed the Metala brand though it was Wolf Blass who really saw the potential of the region, particularly the distinctive characters of the cabernet which was used in many blends.
Today four large production facilities exist in the region, the Belvidere winery, Langhorne Creek wines, Bleasdale winery, and Step Road.
Aspects of the Terroir
It is commonly accepted that the ripening conditions of grapes are modified by proximity to a large body of water and this is likely the case with Langhorne Creek and its frontage to Lake Alexandrina. The district is also only 30-35 kilometres inland from the Southern Ocean.
Both bodies of water will have a strong influence in regulating temperature particularly during the critical ripening period.
There are two types of vineyard settings.
The original and many recent vineyards are planted on the floodplain of the Bremer and Angas Rivers which flow into Lake Alexandrina. The soils from the upland areas formed on the old rocks of the spine of Fleurieu Peninsula and have been eroded and washed downstream and redeposited as alluvium that is tens of metres deep. This is a process that is repeated any time the two rivers flood. Most of these vineyards have an elevation of less than ten metres. They are called here the 'flood plain soils'.
Many of the newer vineyards are planted on an older surface that is largely flat but is slightly higher than the floodplain vineyards and have an elevation generally above ten metres. The origin of the underlying rocks is not defined on the geological maps but may be related to an earlier and much larger lake system. The rocks are calcareous and the overlying soils include wind blown sediment and remobilised calcium redeposited as 'calcrete'. These soils are referred to here as the 'upland calcareous soils'.
Calcium readily goes into solution and redeposits to form nodules and sheets, termed calcrete, which are an important near surface feature of much of the landscape of arid Australia.
The 'flood plain soils' are very young and have been deposited over the last 10,000 years. The 'upland calcareous soils' while recent are partly derived from sediments that date back several hundred thousand years.
Interestingly Michael Potts, winemaker at Bleasdale, feels there are taste differences showing up between these two landscape surface types.
The fluctuation of the sea level, the result of growth of the ice caps and their subsequent melting will have played a significant role in the development of the landscape at Langhorne Creek.
The growth of the ice caps, principally the Antarctic cap, lowers the sea level and at the height of the cycle by as much as 100 metres from the current level. The last cyclical peak of the ice caps was about 105,000 years ago. The consequence of this is that as the ice caps grow towards a peak the sea recedes and the outlet for the Murray River would progressively extend out over the continental shelf. Lake Alexandria, assuming it existed back then and it probably did, would drain and a large valley would be cut across the continental shelf as the Murray River flowed to its new outlet.
The increased gradient of 100 metres has been partly responsible for the river bank cuttings that extend up the Murray River to Morgan and beyond. It would also mean that any alluvium that had accumulated in the Bremer and Angas River valleys would be re-eroded and flushed out to sea as the high water point of Lake Alexandrina retreated.
From the glacial high point 105,000 years ago there has been a series of smaller icy peaks and warmer troughs to the present. The current warm period that began about 10,000 years ago with a corresponding rise in sea level led to the flooding of Lake Alexandrina and as a consequence the filling with alluvial sediment of the Bremer and Angas river valleys.
The glacial cycle that the earth is experiencing now probably marks the high point of the sea level before the earth again experiences the on-set of icy periods and a lowering of ocean levels. The history of the current ice age which goes back several million years has been very accurately mapped, particularly the last 500,000 years, and it is known that the time from maxima to minima in ocean levels is about 105,000 years.
For Australia the last 500,000 years corresponds with the general onset of a warm, dry, windy climate from a wetter, more humid climate. This steady climate change combined with the repeated infilling and eroding of the Bremer and Angas Rivers with the ice-age fluctuations are the important influences that have developed the Langhorne Creek landscape.
In summary while the soils of Langhorne Creek have a different origin-a range to the west versus a range to the east- to those along the banks of the Murray River they are not dissimilar and share an alluvial source combining with wind blown sediments and mobilised calcium redeposited as nodules, layers and hardpans.
In this respect Langhorne Creek can be thought of as the most southerly of the vineyards that border the Murray River and which extend all the way back to Rutherglen near Albury-Wodonga. As an experiment in taste and grape flavours it would be interesting to see what changes happen as you proceed along the Murray River from the sea level vineyards of Langhorne Creek, slowly getting higher and higher as you trace the Murray back eastwards to Rutherglen.