Terroir

The formation story of our terroir commenced approximately 400 million years ago during the Ordovician era, a time when the seas were rich with ammonoid molluscs (shellfish). At this time, Australia was the most eastern portion of Gondwana and rested across the equator with warm coastal waters, coral reefs and bountiful sealife. Over the next 400 million years, the shellfish which inhabited these reefs and coastlines were compressed into very high-grade strip of limestone running along the western edge of the Great Dividing Range - which you see at the nearby Jenolan Caves.

Our vineyard resides upon one of these ancient coral reefs. The limestone, which extends under our vines, was mined just south of our vineyard for the nearby Kandos Cement Works to make the cement which built the Sydney Harbour Bridge and much of Sydney during the 20th Century.

Approximately, 150 million years ago, during the Jurassic period (Mesozoic era) as the great super continent of Pangea was fracturing and water started to cover the rift valley between Europe and North America, the coastline of France was a long way inland from its current location. This coastline traced a course from the cliffs of Dover around Champagne, through Burgundy and then roughly towards what is now the Atlantic Coast through the Loire Valley. At the same time, the climate of France was closer to current day Miami. These shallows seas covering north west and south west France were teeming with aquatic life with shorelines rich with shellfish and waters filled with Plankton. These plankton and shellfish deposited into layers of calcareous sedimentation. Over the millions of years the plankton converted into the chalk of Champagne and the shellfish metamorphosed into thin, elongated deposits of limestone tracing the old shoreline (parts of which are called the Kimmeridgian chain). These limestone deposits, driven upwards into scarps by faulting at the time the Alps formed and mixed up with clay and sand into marl, form the basis of the different Burgundian wine regions from Chablis in the far north, through the Côte d’Or (Côte de Nuits, Côte de Beaune) down to Maconais. The premium vineyards of Burgundy closely hug these narrow soil profiles. Hence the Côte d’Or vineyard planting region is 65 kilometres long by only 1.5 kilometres wide. In much of Burgundy there is no limestone in the soil - and no vineyards planted.

The different geological structures of the Rylstone region are most evident by the volcanic rock (Rylstone Volcanics) overlaying much of the limestone (Coomber formation) which appear in isolated locations where the lava flows ceased, or the volcanic rock has been eroded. Due to the hardness of the volcanic rock, it tends to form the highpoints around the area. The boundaries of the two rock types are very clearly defined.

Our vineyard closely hugs the narrow (1km wide) limestone formation which runs in a relatively north-south trend just west of Rylstone and our plantings stop wherever the soils turned to volcanic rock. The driveway down into the vineyard has volcanic soils on the eastern side (Rylstone/Kandos town side) which have been left as pasture, and limestone infused soils on the western side sloping down to the River which have been planted with vines.

Volcanic rock is incredibly hard and acidic, making fracturing for root growth difficult and the acidity makes the soil micro-organisms less efficient, meaning they require more soil to produce the same mineral availability for the vines. It is for this reason that limestone infused soils with their high pH (and mild alkalinity) can be vastly shallower. In fact, some of the best vineyard soil in France can be as shallow as 30cm in the Côte de Blancs in Champange (where many of the best Blanc de Blancs Champagnes are found), or less than 50cm on the Grand Cru midslopes of Burgundy.

Cistercian and Cluniac monks figured out that different soil types and locations could dramatically influence a wine’s character. They subsequently divided vineyards into some 1,463 patches surrounded by rock walls, known as “climats”. Variations in soil are broadly categorised as physical and chemical. Physical differences in soils such as depth, layering, consistency, water retention, coarseness and structure all impact on the growth habit and resultant fruit of the vine. Chemical differences are perhaps more subtle, and include acidity (and alkalinity), macronutrient availability, micronutrient availability, chelation and soils microflora. These two elements are deeply interconnected and manifest as an endless variety of nuance and variation in grape, must and wine flavours. The best vineyards in Burgundy (e.g. Romanee-Conti) are situated on the mid-slope where erosion keeps the soil relatively shallow, but there is more top soil than the higher slope areas where erosion exposes the limestone in spots.

Our vineyard soils are relatively shallow, ranging from less than 20cm with limetone poking through at the southern end to over a metre depending on the pooling of soil from erosion (Colluvium/Slope Wash) from the slopes above. There is much variance, as to be expected from a 55-hectare vineyard which covers 1.5km of rolling hills and then up a slope, but the result can be very shallow root zones and, depending on the exact soil composition, very good drainage reducing the availability of water. This reduces vine vigour and concentrates the grapes - improving grape colour and flavour intensity. With experience, we have gradually reshaped parts of our vineyard to their most appropriate varieties. Our Cabernet is planted on the deepest soils, which they love, where slope wash has pooled over the millenia. Whereas our Chardonnay is planted on the shallowest soils in the vineyard. We are 500 years behind Burgundy where the Cistercian and Cluniac monks figured out all the soil types beneath much of vineyard from centuries of meticulous record keeping, but with the help of science, we are hopeful that we may get a handle on it within 50 years.

Climate is the final piece of the terroir puzzle. It is an important piece, but less so than soil and geology. There are many valleys in Burgundy sharing the same temperature and inland location, but only one Côte d’Or. Climate drives elements of the vine’s growth and grape ripening which are largely determined by Sunshine, Aspect, Heat Summation, Rainfall, Humidity, Wind and Diurnal patterns (daily temperature variation). Every vineyard location in the world is unique and on a micro-climate level there can be great variations – we have watched storms cross parts of the vineyard soaking them and leaving other areas dry, and we also have areas where cold air pools and where there is higher exposure to wind.

Rylstone is located on the western slopes of the Great Dividing Range, ~160 kilometres from the coast. The natural wind direction is also from the west, i.e. further inland making them dry. Temperatures can easily change 25 to 30 degrees in a day and the dry inland winds reduce humidity, and therefore some disease risk. The coolest temperature we have recorded is minus 14 degrees. Our location west of Rylstone is also in a rain shadow driven by the large water mass of Lake Windamere to our West which breaks up storm fronts and as we’re on a rising slope toward the peak of Mt Coomber Melon with two large valleys starting either side, the wet weather is directed to the north down the Bylong Valley and to the south down Capertee Valley.

We produce Burgundian/Champagne varieties and Bordeaux and Rhône Valley varieties. This was driven by an initial need over the past 20 years to sell large portion of our grape production to other wineries to provide cashflow to fund our own winemaking operations; and in the 1990s, there was a heavy focus on Bordeaux varieties (Cabernet Sauvignon, Merlot, Semillon) and Rhône varieties (Shiraz) across Australia – so we planted what was in demand. The net result has been some wonderful discoveries. With beautiful, textural and perfumed Cabernets; and smooth, long Shiraz pointing to the use of continental and maritime as a guide rather than a rule book for vineyard site and grape variety selection.

The altitude of our vineyard (600 to 650 metres) produces a very cool climate, accentuated by the sandy-loam on limestone soil structure which retains very little heat and makes us as cool as the higher elevations of Orange with its 'warmer' volcanic rocks or the southerly latitudes of Central Otago and Tasmania. Once the sun sets, all the day’s heat is quickly lost – and produces a vintage which is arguably one of the last on Mainland Australia, and more in line with Tasmania and Central Otago New Zealand. A later vintage means longer and slower grape ripening, which can result in better grape acid and sugar balance at harvest. Critically for us, the growing season temperatures of Rylstone are on average very close to Champagne and Burgundy.