Dr. Mat Goddard, evolutionary biologist and senior lecturer at Auckland University, studies natural yeasts, especially those yeasts involved in winemaking. Recently, he and his team at the Auckland University Faculty of Science, conducted a study into indigenous yeast populations in vineyards throughout the Marlborough. The study compared yeast populations in conventional, organic, and biodynamic vineyards and found that there were larger populations of unique yeast species in organic and biodynamic vineyards, than in conventional ones.
According to the research report, ‘Fungal communities of New Zealand vineyards‘ by Peter Morrison-Whittle, “seven biodynamic vineyards and six conventionally managed vineyards were sampled in the Wairau Valley… Fungal communities of soil and fruit differed significantly between the conventionally managed and biodynamic viticulture vineyards.” *
Sam Weaver studied microbiology at London University and is now a winegrower at Churton, a vineyard property located on the southern hills of Marlborough, between the Waihopai and Omaka Valleys. In 2000, Sam and his wife Mandy planted pinot noir, sauvignon blanc, viognier and petit manseng on the property. In 2012 Mat Goddard and his team of research scientists brought their studies to bear on Sam’s biodynamically managed property, and found not only an increase in yeast species populations, but that Churton is home to 22 strains of Saccharomyces cerevisiae, 17 of which are unique to Churton’s Saddle and Loin vineyard sites.
According to another report from the same study, ‘Saccharomyces population diversity‘ by Sarah Knight, “one strain found in the Saddle block ferments matched to the commercial strain CY3079. All other strains found (did) not match to any commercial wine yeast or to any characterised international strains… The strains that are unique have never before been seen in New Zealand, nor any other country – given the current available data it is fair to say these (yeast strains) are unique to these sites.” *
“Churton is very different from the standard Marlborough model,” says Sam, “because we’re elevated 200m above sea level on an east facing ridge, which, on the eastern side, has rolling cliffs between 40-50m that drop down to a river bed, and on the western side is an escarpment that slopes up to 90m above the valley floor.”
Sam was born in the UK to New Zealand parents, who owned a family farm in Shropshire, called Churton. He started on the path to wine as a merchant in London, where he spent 10 years selling fine and rare Bordeaux, Burgundy and Rhône Grand crus, before studying microbiology and then travelling to New Zealand and working vintage in Marlborough. Eventually, Sam went on to become chief winemaker at Stoneleigh Wines, before leaving to establish Churton with his wife, Mandy. Sam cites the transition from London wine merchant to Marlborough winegrower as a fairly simple one.
“In those days, there was a certain element of snobbishness in the English wine trade, which I didn’t feel comfortable with,” says Sam. “I much prefer doing things… and I feel much more relaxed around winemaking and farming. I’m a rural boy who was brought up in the country side.”
Sam’s experience selling (and no doubt drinking) some of those fine and rare Grand crus back in London, helped him precisely plan out Churton, which Sam reckons is, “an exceptional piece of land.”
“Because of my European wine experience, I was looking for something which is on a hill,” says Sam. “As far as I’m concerned, winemaking is all about site selection, so we were quite careful about where we chose to plant the vineyard… Hills give you all sorts of advantages, such as air drainage, which in a cold region like Marlborough, which is frost prone, means you’re at a much lower risk.”
The Churton vineyard is divided up into 17 different blocks over 22.5ha. Each block has been specifically planted to make the most out of the different aspects of the hill. For example, all the pinot is planted on east facing slopes to catch the first cool rays of the early morning sun, which then get relatively shielded from any searing sunlight in the afternoon. Much of the vineyard is composed of wind-blown clay loess, which has excellent water holding capacity and translates to more steady ripening of fruit and, hopefully, better wine.
“I’m trying to aim at a place where we don’t have such high alcohols and that big sweet fruit character, yet still retain good mature tannins and balanced acids,” explains Sam.
The Churton property is managed using biodynamics, and is certified organic by BioGro.
“For a long time, I thought that (certification) didn’t matter, so long as we did it intrinsically and believed in it,” says Sam, “but because there’s a tendency for so much greenwash, and the SWNZ program, in my opinion, doesn’t go far enough and is confusing, we decided to become properly certified with credible organic certification.”
As a microbiologist, Sam looks at biodynamics from a rational scientific perspective, despite the view that biodynamics isn’t rational, or scientific.
“I think of biodynamics as active biology, and view it as a biological hierarchy in terms of how we manage the property as a single living organism,” says Sam. “The farm is made up of different components but all are interrelated elements of biota. The objective of biodynamics is to look after and encourage microbial ecology, which is the basis for all of biodynamics.”
To encourage this microbial ecology, Churton makes its own compost, which is activated by the biodynamic preparations (502-507), and acts as “a large bioreactor, with the objective being to create large numbers of soil active organisms.” Spreading this compost over the vineyard helps establish and maintain Churton’s microbial population, and, as Mat Goddard’s yeast study suggests, can produce entirely new and unique strains of yeast species.
“Mat found unique species of yeast in our vineyard, which aren’t found anywhere else, some of which are involved in our indigenous ferments in the winery,” says Sam. “So, we have more unique yeast species than a conventional vineyard and also yeasts that are specific to our terroir… I believe by increasing microbial populations in the vineyard, biodynamics specifically links your terroir to your winemaking,” adds Sam.
All the fruit grown on the Churton property is hand picked and, in the case of the pinot, it all gets de-stemmed, and placed into open top fermenters where it is left alone to start fermenting on its own, courtesy of Churton’s unique wild yeast species. Sam utilises the biodynamic calendar in the winery and leaves the must on skins for a whole lunar month, before it’s pressed off and put into barrel, where it can go through malolactic fermentation whenever it’s ready. The wine is then racked and settled, before being bottled with minimal sulphur.
“The wines have an innate stability and our pH’s tend to be lower,” says Sam. “I have much more confidence in allowing things to happen naturally in the winery, because I know the microbiology is sound. Once you’ve got confidence in your microbiology, you realise you don’t need to add anything to the wine,” he adds.
It’s not often that biodynamics has the benefits of a trained scientist, or a detailed scientific study to support the argument for healthier and more effective forms of agriculture and winemaking. But, there you go…
D// – The Wine Idealist
*Download: University of Auckland, Biogeography, Yeast Strain, Churton Study – 2013
† ‘This study has been accepted for publication in the IMSE Journal, part of the Nature Publishing Group. The advance online publication will be available to view on IMSE here, soon.’ – Mat Goddard, July 2014.