Greywacke (and Greywacke Jones)

Greywacke stones along the Haast River in New Zealand

Greywacke (pronounced “grey-wacky”) is a drab, grey stone—technically, a sedimentary rock–made up of layers of very hard, clay-based, muddy grey sandstone criss-crossed through with layers of argillite (a type of mudstone) and grains of quartz, feldspar, and other small rock and mineral fragments. The term Greywacke can refer to the entire rock (or boulder), the sandstone base of the rock, or—especially in the case of wine enthusiasts, a type of soil derived from the stone.

In case you are wondering how such a plain looking rock acquired such a crazy-sounding name, “wacke” is the German word for sandstone, and the term (Grauwacke) was first used to describe rocks located in the Harz Mountains of northern Germany.

Greywacke soils do well with viticulture. The clay-derived portion of the stone weathers into clay-based soil, which is appreciated for its abilities to remain cool, retain vine nutrients, and retain water. The rock and mineral fragments remain behind in Greywacke soil to counter the clay with coarse-grained gravel, providing aeration and drainage. And, of course, some of the rocks stay behind on the top of the soil, absorbing and releasing heat.

Greywacke boulders on Te Mata Peak (Hawke’s Bay, New Zealand)

This gravelly soil is most notably found in the vineyards of New Zealand; which makes sense as hard greywacke stone makes up a large part of the Southern Alps as well as the smaller mountain ranges of New Zealand’s North Island. The famous “Gimblett’s Gravels” soils of Hawkes Bay, as well as large swaths of Marlborough, Gisborne, Canterbury, and Nelson are all Greywacke-based. Greywacke is almost considered the “national stone” of New Zealand (or would be, if New Zealand ever decided to have a national rock, according to The Encyclopedia of New Zealand.) Click here for a map of Greywacke in New Zealand.

Fans of New Zealand Sauvignon Blanc (which I certainly am) will no doubt recognize the name Greywacke in terms of a New Zealand wine brand, produced by none other than Kevin Judd – the beloved original winemaker at Cloudy Bay. Kevin continues his string of winemaking successes at Greywacke, producing a range of wine including a delicious albeit typical “zesty” Marlborough Sauvignon Blanc as well as a native yeast-fermented, lees-aged, oak-influenced Sauvignon Blanc (“Wild Sauvignon”) that has become a staple at both my Sunday night dinners and my Intro to Wine Classes. Other Greywacke wines include Chardonnay, Pinot Gris, Riesling, Pinot Noir, and even a late-harvest Riesling—all delicious.

Detail of greywacke soil in Algarve, Portugal

Greywacke bedrock and soils are found in many parts of the wine world, including the Algarve region of Portugal; Germany’s Mosel, Ahr, and Mittelrhein; the Western Cape of South Africa; California’s Russian River Valley; and the Barossa. The term “Greywacke” is used often in the context of wines and vineyards from all over the world, as well. Cosa Obra Wines in the Russian River Valley has a “Greywacke Vineyard” located within the Russian River Valley AVA, about where the Russian River makes it westward turn towards the Pacific Ocean. In Australia’s Barossa, Thorn-Clarke Winery, very much into the soils, produces a Shiraz labeled as “Shiraz on Cambrian Greywacke Soil.”

About that subtitle: There is a character named Greywacke Jones in “Slinky Malinki,” a children’s book by New Zealand author Lynley Dodd. Greywacke Jones is a mischievous grey kitten who hangs out with her pals Slinky Malinki, Hairy Maclary, Butterball Brown, and the rest of the gang. So now you know.

References/for more information:

• Robinson, Jancis and Julia Harding: The Oxford Companion to Wine, 4rd Edition. Oxford, 2015: The Oxford University Press
• http://www.winereviewonline.com/Gerald_Boyd_on_Greywacke.cfm
• http://www.teara.govt.nz/en/rock-and-mineral-names/page-1
• http://greywacke.com/
• https://www.amazon.com/Slinky-Malinki-Hairy-Maclary-Friends/dp/0140544399
• https://www.cosaobra.com/winery/vineyards/greywacke
• https://flexiblelearning.auckland.ac.nz/rocks_minerals/rocks/greywacke.html
• http://www.thornclarkewines.com.au/wine/2008-shiraz-on-cambrian-greywacke-soil/

The Bubbly Professor is “Miss Jane” Nickles of Austin, Texas… missjane@prodigy.net