How do organics and biodynamics affect a vineyard’s carbon footprint?

Vineyard cover crops
Vineyard cover crops

An online debate around the carbon footprint of organic and biodynamic viticulture, as well as sustainable vineyard methods in a broader sense, was hosted in May by the Porto Protocol Foundation – a non-profit organisation committed to mitigating the effects of climate change.

The foundation was created by Taylor’s Port following a series of environmental events in Porto in 2018 and 2019, and it now has hundreds of members all around the world who share ideas on climate-positive winemaking.

The recent debate, which was part of a series of online Climate Talks, was hosted by David Guimaraens, head winemaker and technical director of Taylor’s Port owner The Fladgate Partnership. The panel included:

  • Diana Snowden Seysses, of Domaine Dujac in Burgundy and Snowden Vineyards in California;
  • Austrian Fred Loimer, winemaker and founding member of biodynamic certifying body Respekt;
  • and Stan Zervas, vice president of viticulture at Silverado Farming Company in Napa Valley.

Organic vs biodynamic

With each of these winemakers practicing a style of eco-friendly viticulture to suit their specific estate, they began by discussing of the relative merits of organics, biodynamics and broad sustainability policies in general.

‘We currently farm 35 different vineyards that fall somewhere in the spectrum of sustainability,’ said Zervas. ‘But my personal bias is towards organic; I think there’s a large benefit in switching from conventional to organic.’

Making wine in both the New and Old Worlds, Snowden Seysses offered perspective on having to adapt viticultural systems to both site and business model. In 2003 she became oenologist at Burgundy’s Domaine Dujac – the family estate owned by her husband Jeremy Seysses – and has also been winemaker at her family winery, Snowden Vineyards in Napa, since 2005.

‘When I started working with my in-laws in 2001, they were already starting with biodynamics,’ she explained. ‘The biggest shift is giving up herbicides; there’s better soil structure, more moisture [and] more organic content, they just look more alive.’

Observing this change persuaded her to push Snowden Vineyards towards organics. ‘The first step is to have a healthy ecosystem in the soil. Biodynamics is just extra costs and although I love biodynamics, my family’s finances just weren’t there yet.

Fred Loimer began to convert his family’s estate in Austria’s Kamptal region to biodynamics in 2006. He also pointed out the additional resources need to commit to biodynamics.

‘The biggest challenge in changing was more power: you need more manpower, you need more machine power, you have to spray. You see quite a quick reaction in your vineyards – not always positive; some vineyards get poorer and poorer,’ he added.

Key for Loimer was discovering the ‘soil life’ and natural rhythm of his vineyards. ‘You have more balance in your vineyards so they don’t have this hysteric growth, which you see in conventional vineyards. You see a nice difference between the phases of a year: spring, summer, autumn. And you see a big difference in the grapes. They look different, they taste different.’

Measuring a carbon footprint

This increase in labour that comes with converting to organic or biodynamic practises can create a higher carbon footprint.

‘Some people claim that to run vineyards organically, you have to significantly increase the use of tractors to spray and manage weeds, and therefore there’s more negative impact on your carbon footprint from the increase in fuel use,’ explained Guimaraens.

How can this be counterbalanced?

‘If you use a herbicide, you spray at one time and you’re done for the year,’ said Snowden Seysses. ‘But I don’t think there’s a really good calculation of the carbon imprint of the different farming methods. Are calculations taking into consideration the fact that you’ve killed the soil and are no longer absorbing carbon dioxide out of the environment?.’

Zervas said, ‘We’ve been really trying to do carbon budgets for some of our vineyards, and it’s pretty interesting how much carbon is sequestered in organic matter. So, yes, it’s more tractor passes, but as you do the math, if I can up the soil organic matter by half a per cent or a per cent, we sequester much more carbon than expended by extended tractor passes.’

The nitrous oxide released from chemical fertilisers is another factor. ‘Nitrous oxide is 294 times more damaging than carbon dioxide. In biodynamic and organic viticulture by not using chemical fertilisers you greatly reduce the carbon footprint from just that point alone,’ said Guimaraens.

Looking ahead, Snowden Seysses raised the idea of converting carbon that was captured at the top of fermenting tanks. ‘We have all of our hectares’ worth of vineyards in one place for a three-week period,’ she noted.

‘All of this carbon dioxide is coming out of that sugar in one place – and you can capture it. We need chemical engineers to figure out how to sync that carbon dioxide into minerals. Seashells do it, chickens do it; it is do-able, but someone needs to figure out how to do that.’

Natural resources

Part of assessing a winery’s carbon footprint is its use of resources, including energy and water. ‘Biodynamics is a holistic system and producing everything you need is one of the main concepts,’ said Loimer. ‘We do composting with our own materials, we try to get manure from cows and horses. We try to work with the resources that we have.’

Snowden Seysses pointed out that in practical terms, the economics of renewable energy don’t always work for individual wineries. ‘Seven kilometres from Domaine Dujac there’s a place that combusts wood and turns it into electricity or hydrogen cells. But it would cost four times what we pay for our gas to heat our buildings, to use the cuttings from our own vineyard,’ she said.

Water use was also a hot topic. ‘Irrigating vines has a negative impact on the carbon footprint. Both because of the energy used to pump water, but also because of the greater release of nitrous oxide,’ explained Guimaraens.

Should irrigation be an acceptable practice for sustainable, organic and biodynamic agriculture?

‘It’s not really sustainable and it has nothing to do with the holistic biodynamic system, because you’re pumping water from somewhere else, so it’s not a resource from the farm,’ said Loimer.

‘But sometimes irrigation is really the last helping hand,’ he added. ‘We have some vineyards on terraces where you only find 30-40cm of brown soil on the rock. And we have Grüner Veltliner, which is a variety that needs food and water. So, it’s a compromise at the moment, to use irrigation in these vineyards.’

In practical terms, converting an irrigated vineyard to dry farming would be time-consuming and costly, involving trials of grape variety, rootstock and site selection. ‘Australia has been looking at southern European grape varieties which are naturally more drought resistant,’ pointed out Guimaraens. ‘So we do have tools. But things take time, they take money.’

In the New World, historically there was a tendency to choose the grape variety that would give the desired style of wine, which was not necessarily the variety best suited to an individual site, ‘but surely this must be the way the world should be progressing in order to reduce the need to irrigate vineyards,’ noted Guimaraens.

‘Unfortunately the variety is often driven by market conditions, and what will sell and what people want,’ said Zervas. He noted that there is interest in dry farming in California, however.

‘It’s more from a California drought situation and knowing that water would be in short supply. How do we figure out how to grow great vines without using much water or using less? It is a growing interest, but we’re really just getting back to techniques of our grandfathers, more than we are inventing something new.’

Snowden Seysses works with some vineyards in California that are dry farmed, planted on drought-resistant St George rootstock. ‘St George is already a low-yielding rootstock and then on top of that, if you’re not irrigating you’re going to have tiny berries,’ she explained.

‘So it’s really a financial issue. I think frequently all choices ecological come down to financial choices.’

An international standard for sustainability?

With such diversity in winemaking practices – even among a group of winemakers who are ecologically minded – how can wine drinkers make positive choices about the bottles they buy?

‘Organic and biodynamic standards are much more consistent, but with sustainable viticulture, there aren’t really rules which guide people in every country. Should there be a global standard for sustainable viticulture?’ asked Guimaraens.

‘I currently have five different organisations that will do sustainable certification for us,’ noted Zervas.

‘They’re all quite similar. Which one do we do? I don’t know. But I think if you’re going to use the word “sustainable” in marketing and sales, in promoting to the general public, there should be a standard – and I’d love to see an international standard. I’m a little sceptical we can get there, but I guess it’s possible.’

Loimer agreed. ‘Especially for the consumers, yes, you need certification. There are too many winemakers who are saying they’re almost organic or very much biodynamic, but they’re not interested in certification because that’s too much paperwork. Of course it is. But it’s needed, so that when the consumer buys something they feel safe that that’s what’s really in the bottle.’

He concluded: ‘Certification, I would say at the moment is important. Maybe in 50 years everyone will be working biodynamic and then it’s not necessary!’


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Source: Julie Sheppard