“Hawke’s Bay is a bit of a victim of its own success,” explains Northern Irish born, winegrower Dermot McCollum, from his vineyard home in Hawke’s Bay, New Zealand, “in that you can have a really good mix of wines that can match it with some of the best of the country, but because we do a lot of good things well, (the region) sometimes suffers a bit, because there’s no known single wine from here, like say Central Otago pinot, or Marlborough sav, which we can say, ‘this is what we do best’.”
The Gimblett Gravels Winegrowing District, located within the wider Hawke’s Bay winegrowing region of New Zealand, was once considered a poor, infertile place, with very few prospects for growing a crop of anything well. The area is located on an ancient riverbed, which features very stoney soils, mostly comprised of hard sandstone known as greywacke. As a result, the land was turned over to warehouses, drag racing strips and a rubbish dump. In spite of this, Stonecroft’s former owner and founder Dr. Alan Limmer, planted cabernet sauvignon and some syrah in 1982, and it became one of the first successful vineyards in the Gimblett Gravels region.
“There were some initial vineyard plantings in the region in the late 70’s,” says Dermot, “but the early 90’s was when the vineyards in this area really started to take off.”
A former chemical engineer, Dermot moved to Hawke’s Bay from London in the late 2000’s, with his New Zealand wife, Andria, to begin their new life as winegrowers. Firstly, Dermot did a couple of vintages on Waiheke Island and then in Burgundy, France, before friends notified them that the pioneering Stonecroft vineyard was for sale. They purchased the property in 2010 and immediately set about putting their own stamp and style on the place.
“We started converting the vineyard over to organics from day one,” says Dermot, “… from a health perspective, and the fact that I’m not too comfortable handling or using pesticides or insecticides.”
Despite the relative northern climes, compared to, say, Marlborough, or Central Otago, Hawke’s Bay is still considered to be a cool climate region, with days in the summer growing season very rarely reaching above 30˚C, and in the winter times, often reaching below -2 or -3˚C.
“The property is suited to an organic management regime,” says Dermot. “The gravels are very free draining, we have low humidity, low rainfall, and so it’s actually not that difficult to manage the vineyard in this way, compared to a conventional vineyard.”
Before Dermot and Andria bought the property, Stonecroft was managed conventionally, relying upon synthetic chemical substitutes to give the vines their nutrition fix, to help the plants grow.
Plants rely upon thirteen basic nutrients, including three primary macronutrients; nitrogen (N), phosphorus (P) and potassium (K). A growing plant will generally use quite a lot of these primary nutrients to flourish and survive, so these elements must be replaced periodically in order to sustain plant productivity. When Justus von Lieberg discovered (1840s) that nitrogen was an essential plant nutrient he revolutionised the agriculture industry by saying that, ‘plant growth is not determined by the total resources available, but by the scarcest available resource’, and arguing against the role of humus in plant nutrition, claiming that existing soil humus provides enough carbon to support the growing plant.
Today, we know that a healthy plant requires so much more than just those three primary macronutrients and the existing humus content to survive, grow and flourish. Synthetic fertilisers don’t support microbiological life in the soil, and in fact, kills a large percentage of the beneficial microorganisms. These microorganisms are essential for breaking down the organic matter in the soil, unlocking the essential nutrients and making them available to the plant.
“We struggle a bit with vine nutrition,” says Dermot, “because the soil is very boney, and we struggle to get enough nitrogen into the vines. There’s no real quick fix for organic producers, so it’s taken some time to get the vines used to the new (organic) regime.”
To get the plants their nitrogen fix, Dermot makes his own compost from the discarded skins, stems and seeds of the grapes after the crush, otherwise known as grape marc, and combines this with certified organic compost purchased from a neighbour down the road. Dermot also buys in some fermented seaweed, which gets applied to the vines as a foliar spray.
“We just use a different suite of inputs to nourish the vines, which are more natural, compared to a conventional grower,” says Dermot. “After the second year of organic management, we noticed the skins of the grapes were thicker and more robust, which I think feeds into the wine in that they seem to have a little more structure about them. Also, the colour intensity in the wine has improved, which is especially noticeable in our red wines.”
Dermot’s approach to winemaking at Stonecroft is, in his own words, “fairly hands off.”
“We hand pick everything,” explains Dermot, “and with the reds we de-stem and crush into open top fermenters. The juice is fermented using indigenous yeasts, and left on skins for a while before being pressed off into barrel… We’ll inoculate for malo and leave the barrels in a warm cellar to encourage it to finish the secondary ferment, before racking it once and transporting it back to a cool cellar and leaving it for about eighteen months, or so.”
Dermot makes very few unnecessary additions to his wines, and relies upon wild yeast ferments to transform the grape juice into wine for all of his wines, except the sauvignon blanc, which doesn’t come from the Stonecroft estate, and is grown conventionally.
“Every wild ferment I’ve done has always gone dry,” says Dermot,” I’ve never had to restart a single ferment or had any problems with them… I’m not averse to making additions to my wine, if it will help them, but I generally try and avoid making them, just because the wines don’t need them.”
Dermot freely admits to adding some enzyme additions to his gewürztraminer to help improve extraction, but hasn’t ever used any acid or tannin products to try and improve the wine.
“I don’t think I was ever going to be a particularly techy winemaker,” explains Dermot, “and maybe, it’s because I haven’t spent a lot of time in a learning institution that tells you ideas about making adjustments to wine… I think all the shaping is already done out in the vineyard, so it’s a bit late to try and do something once it’s gone into tank.”
Stonecroft has two vineyards which are 100% certified organic, and another currently in conversion to organics. Assure Quality, which is a commercial company owned by the New Zealand government and provides, ‘food safety and biosecurity services globally to the food and primary production sectors’, certifies both vineyards.
“I think that if you’re going to make any claims that you’re organic,” says Dermot, “you have to be certified. There are those who make claims about operating organically, but continue to use conventional sprays. To have any credibility you need to be certified.”
As for why Dermot and Andria decided to convert Stonecroft to organics in the first place…
“We’ve never really considered doing it any other way,” says Dermot, “because if you can do it organically, why wouldn’t you?”
D// – The Wine Idealist