In the Heart of the Volcano

Wines, in all their nuances and varieties, are intrinsically linked to the soil of the vineyards. The nutrients of the soil and the climate in which the grapes flourish are inseparable components that give them their subtly and flavour. For a truly unique taste to titillate the senses, the grapes must grow from truly unique circumstances. This here, dear readers, is where an investigation sparks – more specifically, an exploration into volcanic soil and how it contributes to the richness of a finely nurtured vintage. To inspect this fascinating soil and all its wonders, Wineries of Victoria’s Robin Harper sits down with the vineyard manager at Boat O’Craigo, Andrew Mills. Together, they will discuss what the soil contributes to the wines and the richness it yields.

Boat O’Craigo produces grapes from two distinct sites: Healesville and Kangaroo Ground. According to Mills, the Healesville site has “alluvial soils and remnants of riverbeds and rocky alluvial reefs”, he says. It’s “southerly aspect and climate is very cool and wet” and is “suited to our white and most pinot varieties”, he says. While this climate and soil yields delicious results, the focus of this article centres around Boat O’Craigo’s other site and the unique properties of its soil. It isn’t every day that a vineyard is grown on volcanic soil, after all. And so, let us continue with this fascinating thread of complex viticulture and see where it takes us, shall we?


To begin, we must first dissect the components of volcanic soil and why its special properties make it prime acreage for grape growing. “Kangaroo Ground is perched high on an extinct volcano with a capping of black volcanic soil and dark brown clay with floating basalt subsoil,” says Mills. It is the ideal location for Boat O’Craigo’s red wines.

Part of what makes the volcanic soil at Kangaroo Ground so intriguing is its capability to grow grape varieties, such as grenache, that would not be considered feasible in cool climate environments. “The black soil creates a warming [effect], which allows us even in difficult wet seasons to ripen our reds like no other site in the Yarra Valley,” explains Mills. This includes shiraz, cabernet sauvignon, grenache, gamay, and two trial clones of pinots that, according to Mills, have shown “outstanding results”. The properties of the soil produce “intense flavours and colour and balance,” which contribute to the uniqueness of this particular area. While Boat O’Craigo have deemed this area the ideal place for its red varieties, Mills believes that he could grow “almost any varieties of grapes on the Kangaroo Ground site”. This is in contrast to the Healesville site, where varieties such as late ripening reds cannot grow. This means that Boat O’Craigo has the best of both worlds, and has the freedom to produce a vast range of wines for its guests.


The Yarra Valley has a long and rich history as Victoria’s first wine-growing district, which dates back nearly 180 years. Led by early settlers, the region continues to thrive to this very day. According to Mills, Boat O’Craigo has the only vineyard in the Yarra Valley with black volcanic soil. “Neighbouring properties would see some benefits, but being that we are positioned on the highest point of the extinct volcano, the soil here is at its best,” he says. “Other Yarra Valley sub-regions have red or orange volcanic soil,” he further explains.

When it comes to what the soil contributes to the wines it yields, the explanation is quite scientific. “There are numerous benefits of [Kangaroo Ground],” Mills says. “The black cap of approximately 300mm is nutrient rich. When wet, this cap is very plastic-like; when dry, [it is] crumbly and firm, providing a protective layer,” he continues. It is because of the conditions of the soil that the hill remains sturdy, even to this day, with no risk of erosion, root compactions or wet feet, as drainage is optimal. The soil’s mulch-like consistency “provides warmth during later ripening periods and protection for the subsoil” during cool, wet periods. The mineral-rich subsoil and its warming components imparts ripeness and maintains balance and acidity.


Location of the soil is paramount, but so too is the maintenance of the soil to guarantee the longevity of its richness and nutrition. Boat O’Craigo has an ongoing program that is “primarily organic” to promote the health of its soil, using mushroom compost, among other composts, to encourage biodiversity. “We also side throw mid-row cover crops to assist in not only sun reflection for ripening, but also more organic material,” says Mills.

Due to the high standards of Kangaroo Ground’s vintage, the site has yielded a range of award-winning wines that were all awarded points in the high nineties. Namely, the 2015 First Duke Shiraz, the 2015 Braveheart Cabernet Sauvignon and the 2015 Black Cameron Shiraz. All these sensational vintages contributed to Boat O’Craigo being awarded the ‘Dark Horse Award’ from James Halliday – “a testament to the capability of the site and soil,” says Mills.

For self-proclaimed wine lovers across Victoria – or to those travelling to Victoria – it would be a great loss not to taste the reds from this unique location for yourself. Dare to be adventurous and try the yields from this black volcanic soil today.

Robyn Harper-Wineries of Victoria