"Limestone - Holy grail or charismatic illusion?"

"Limestone - Holy grail or charismatic illusion?"

Alex Maltman, The World of Fine Wine, July 28 2022


If there was one rock that is synonymous with great wine, it is the softly textured, comparatively dissolvable, limestone. It is extremely rare in Aotearoa New Zealand where the climate and topography is conducive to fine wine. The five Pyramid Valley Botanicals Collection wines come from soils with deeply influential limestone stories, a rare expression of fine New Zealand wine. The 2022 vintage is the first release of these five wines together, so we thought a story of limestone is due.

How did it get to Waikari?

Imagine this. Some 250 million years ago the Bourgogne was a warm, emerald lagoon teeming with algae and shellfish. We were one big landmass and dinosaurs ruled. Skip forward to 60 million years ago, what is now the Waikari basin in North Canterbury was also submerged under a warm sea teeming with algae, shellfish and plankton. The dinosaurs were extinct, apart from the bird versions, and our Waikari lagoon was home to some strange and wonderful creatures, including giant penguins and birds with teeth. As the algae, shellfish and plankton thrived and perished over millions of years in both places, they decomposed and settled on the lagoon bed as calcium carbonate, the base material for what we know as limestone; and marine marl, a mix of sediment and calcium carbonate. They became compacted and manipulated under the weight of water and millennia of earthquakes and eruptions, eventually being thrust into the open air. Centuries of decomposition alongside the plants and animals of that period, limestone became the bedrock of the soils of Burgundy and Waikari in North Canterbury, home to the vineyards of Pyramid Valley and Bell Hill. By a stroke of luck, or devine intervention, these rare limestone based soils settled in a way, and in a climate, suited to the making of fine, genuinely cool climate Chardonnay and Pinot Noir. This combination is rarer than a tuatara in the wild!

Limestone is very different to all other rocks, because it is soft and dissolves (be it slowly) in water, meaning that fine particles in the soil tend to disappear. This leaves a coarse, stony, well drained soil ideal for fine wine production in the moist climates of Burgundy and North Canterbury. Somewhat contradicting this is that as limestone weathers, the gaps between the particles within the rock become a home for water that tends to be released slowly to the vine. Another trait is they are calcareous and naturally alkaline, whereas all other common winegrowing soils are acidic. In this sweet spot, all of the complex nutrients and minerals, especially calcium and magnesium, are available to the vine. More importantly the wonderful bacteria and fungi that are the life of the soil, thrive in these slightly alkaline conditions. So for lots of reasons limestone is special, there is no other rock like it! These soils are home to Lion’s Tooth, Earth Smoke, Field of Fire and Angel Flower, the wines from Waikari in the Pyramid Valley Botanicals Collection.

Pyramid Valley Waikari Farm

There is also another story, one of pedogenic lime, literally meaning limestone made by the soil. Again this happens in very select locations, once again a result of an ancient sea and decomposed shellfish, but nowhere near as abundant as the true limestone soils. Pedogenic limestone comes from rain that has absorbed carbon dioxide and when it moves through a soil, encounters calcium, from the ancient shellfish, and forms calcium carbonate. These little lumps of calcium carbonate remain in the soils because pedogenic lime only occurs in relatively arid winegrowing climates such as Mendoza and Central Otago, and sort of attract one another to form soft rocks in the soil. They can look like the granules of calcium you find in aged Manchego or Parmigiano. Their impact on the soils seems to be more chemical, as the soft pedogenic lime is slowly dissolving, meaning once again the soil is awash in calcium and is slightly alkaline. These soils are found in parcels throughout our Mānatu vineyard in Central Otago, home to Snake’s Tongue, part of the Pyramid Valley Botanicals Collection.



Pyramid Valley Mānatu Farm

So, what does limestone do to the wine? The science is inconclusive, however Alex Maltman, in his article and is the title of this piece, described it very eloquently, “Most commonly the trait is expressed with words like “liveliness”, “edge”, “nervousness” and “finesse”, perhaps in line with the notion that the alkaline, high-pH soils of limestone produce low-pH wines.” We would add, that in our Chardonnay from Waikari we see a “saltiness”, and in Snake’s Tongue from Mānatu a “chalkiness” to the tannins and feel on the palate.

There are some truly great Chardonnay and Pinot Noir made in Burgundy from these limestone clay soils, and maybe we share some of the same potential given we share a similar climate, and an extremely rare, ancient history of our soils. Time will tell.

Steve Smith MW
Founder and Estate Director
Pyramid Valley, Smith & Sheth, Lowburn Ferry
Aotearoa New Zealand Fine Wine Estates.

October 2024 celebrates the launch of the second vintage of the Pyramid Valley Snake’s Tongue Pinot Noir, from the spectacular 2022 vintage. For a story of the wine and availability click here.
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