While the Barossa and Eden Valleys are both distinct regions with individual characteristics, they are also inseparable in many ways, sharing some similarities and correlations, and with key wine producers often spilling into both. So, while the regional differences are essential to note, it is helpful to consider them together, especially when visiting.
The elevation of the Eden Valley, topping out at 632 metres above sea level, results in lower mean temperatures than most of the Barossa. That climate difference immediately brings some traditionally cooler climate varieties into play, while it coaxes out more elegant expressions from the classic red varieties that are grown across the zone. Much of the riesling is grown at the southern end of the Eden Valley where the elevation is 500 metres or greater, while the shiraz is more concentrated to the north at around or under 400 metres.
What makes the Eden Valley more complex to generalise about is the sheer variability of the terrain, with an array of hills with both gentle and severe slopes and varied aspects and exposures. That results in different macroclimatic influences, which is further complexed by multiple soil types, from grey to brown in colour. Much of the territory is quite rocky, with ironstone and quartz gravel components along with sandy sections. While days can be sunny and hot in the growing season, cooler nights help to promote more delicate flavours and preserve natural acidity.
The Barossa Valley is lower lying and typically warmer, and it receives a lower annual rainfall on average. Given its size, there are naturally variations in soil and geology and the warmth of the valley floor recedes as the vineyards stretch into the hillier sections. In 2008, the Barossa Grape & Wine Association launched a project to document the changes in shiraz fruit grown in different sections of the Barossa. The results are a good general guide.
The northern localities of Greenock, Moppa, Seppeltsfield, Marananga, Stone Well, Ebenezer, Kalimna and Stockwell on the Western Ridge generally have red clay underpinning with a red to yellow brown loam overlay. Elevation is higher but the wines tend to the powerful. Further south along the Western Ridge, vineyards in Krondorf, Light Pass, Tanunda, Bethany, Gomersal, Vine Vale and Dorrien have an array of soil types, with elevation in the mid-range for the valley. Rosedale, Lyndoch, Williamstown and Rowland Flat are further south and at the lowest elevation, with soils ranging from sandy loams to black cracking clays.
