The Natural Winemaker’s Toolkit
A global chorus of producers is taking a stand against chemical farming, bringing natural alternatives to the fight against fungal disease.
Left: Photo courtesy of Domaine d l'Ecu.
BY CHRISTINA RASMUSSEN
Every year Mother Nature makes decisions, some of which are predictable, others which are not. Perhaps no one feels the effects of these climate curveballs more than farmers. In the realm of winemaking, growers all over the world are grappling with “climate chaos”: increased, and sometimes extreme, instances of frost, hail, flooding, and drought that wreak havoc on long-observed growing patterns and harvest rituals. (Take the record-setting rainfalls across California’s Central Coast region this March.) There’s a ripple effect to these shifts. With an increase in storms, for example, comes an increase in humidity, which creates the perfect breeding ground for forms of microbial life—both good and, well, not-so-good. And when microbes threaten the vines, conventional winemakers—who represent 95% of the world’s vineyards and the vast majority of mass-market bottles—turn to synthetic chemicals. Thankfully, as the demand for transparency gets louder, there’s a global chorus of conscientious winemakers asking critical questions about climate change and disease pressure—and innovating ingenious natural alternatives to combat them.
Let’s take one of the not-so-good lifeforms that keeps winemakers up at night: Mildew. Two kinds of mildew—both brought to Europe in the 19th century by American sailing vessels—forever changed the lives of producers. Powdery mildew, caused by the fungus Erysiphe necator, today occurs in most wine growing regions. It can reduce berry size, affect ripening, and both shrivel and split grapes—encouraging other fungal or bacterial infections that spoil wine. Downy mildew, or Plasmopara viticola (long thought to be a fungus but actually a form of algae), needs moist conditions to spread and is found in areas of higher humidity, such as those by the sea or with higher rainfall. If it occurs near flowering, a whole crop may be lost; later in the season, it causes leaves to fall prematurely, depleting yield and grape sugar content and increasing the risk of sunburn. When not managed properly, both mildews can decimate production.
Mildew, a fungus that attacks the health of grapes, can decimate a vineyard.
Only 5% of the world’s vineyards are farmed organically. The vast majority of growers work with synthetics—whether in the form of fungicides, herbicides, pesticides, fertilizers, or all four. Spraying vines with off-the-shelf fungicides efficiently kills mildew, of course. But at what cost? A growing movement of winemakers is asking this basic question, and taking a stand on the effects industrial chemicals have on the soil and the health of vineyard workers.
As Brunnhilde Claux of Domaine de Courbissac in Languedoc’s Minervois says, “I don’t go into my vineyards to get cancer, and I want to disturb my vineyards as little as possible.”
Claux, like many of her low-intervention winemaking peers, eschews chemicals, favouring the organic winemaker’s toolkit. The predominant tool in this toolkit to prevent powdery mildew has long been sulfur—one of the naturally-occurring chemical elements, and the fifth most common on earth. For downy mildew, copper sulfate (a compound that combines sulfur with copper, another naturally-occurring chemical element) remains the only fully reliable solution. However, copper must be used in moderation: it’s a heavy metal which in high doses can cause soil toxicity, and if there is run-off into nearby rivers and lakes it can kill aquatic life. (More on copper in a future column.) What’s more, both sulfur and copper are “contact” sprays, washing off with rain. This means they need to be applied more frequently than synthetic fungicides (which work from inside the plant), resulting in more work and tractor emissions.
"I don't go into my vineyards to get cancer."
-Brunnhilde Claux, Domaine de Courbissac
Inspiringly, there’s a groundswell of activity by Claux and other winemakers who are innovating and rethinking how to fight mildew and other maladies in the most natural way possible. Claux works with sulfur, stinging nettles, horsetail, and symphytum, and as little copper as possible (if at all). In years where downy mildew is a threat, she may do one copper application, but if the threat continues, she simply accepts that she will incur losses. As downy mildew is fairly rare in the Languedoc, this approach is financially feasible for her.
At Domaine de l’Ecu in Muscadet, Fred and Claire Niger work biodynamically, using classic natural preparations such as horsetail teas (horsetail in particular is known for its antifungal properties). But they go a step further, also applying homeopathic “mother tinctures” of summer savory, thyme, and orange essential oil to help prevent mildew. The goal is to work preventatively, building up the equivalent of the vine’s immune system, helping it to less likely to fall sick. As Fred explains, “It’s not about curing, it’s about working to prevent, or to help a plant to recover.”
To apply the tinctures, they must be mixed with milk and black soap to ensure that the oils mix properly. The doses are miniscule—just 10ml per hectare. While Fred says there isn’t a way for them to avoid using copper entirely (Muscadet has a notoriously difficult wet climate), this helps them to keep their doses as low as possible. On average, they need only 2.2kg per hectare of copper, which is well below the EU maximum regulations of 4kg.
“The goal is to work preventatively, building up the equivalent of the vine’s immune system.”
-Fred Niger, Domaine de l'Ecu
Francesc de Frisach of Celler Frisach has been dealt a gentler hand by nature in Spain’s Terra Alta region. Prevailing winds ensure lower humidity, meaning downy mildew pressure is significantlylowered. There is such low risk that they have not sprayed copper for over 20 years. Powdery mildew, on the other hand, can still be an issue. To prevent it, they spray a mix of sulfur and diatomaceous earth. As Francesc explains, “Diatoms arefossilized algae. They dehydrate the fungi so you can control them.In addition, the cell walls contain silica, acting like micro-knives. They cause the plant to excrete phytoalexins, which act like our white blood cells. In other words, this puts the plant's immune system on alert and prepares it to fight against the fungal aggression.”
He also infuses garlic with water, leaving it to macerate for a week in the sun and then spraying it. “Whole garlic contains a compound called alliin. When crushed, this is converted to allicin, the main active ingredient in garlic. Allicin contains sulfur, which is what gives it its distinctive smell and taste. In addition to smelling very bad, it bothers fungi and mammals such as wild boars, so you can control the plague.”
Frisach’s approach is all about sensitivity. He says, “We have been working organically for more than 30 years, but what we say is that we practice common-sense agriculture. It's the way my parents and grandparents worked: a little science and observation.”
“We practice common-sense agriculture.”
-Francesc de Frisach, Celler Frisach
In Burgundy, Morgane Seuillot and Christian Knott of Domaine Dandelion currently fight mildew with a mixture of copper, garlic, fermented plant extracts, as well as milk or whey. The milk is diluted down to 20%, whereas whey is diluted to around 80%. It is thought that milk proteins interact with sunlight to create an antiseptic effect, particularly tackling powdery mildew.
Rajat Parr learnt about the use of milk to combat mildew at Domaine Dandelion in 2019. He was inspired, and in his Phelan Farm vineyards in Cambria, California, he too sometimes uses milk in his ferments. He also works with turmeric, neem oil, nettles, willow bark, oak bark, milk thistle, honey, thyme, horsetail, kelp, seaweed, Pacific Ocean water, and fish-bone emulsion. Sprays are applied throughout the season, in order to encourage a complex, diverse microbial population. Parr explains that this flourishing mycobiome is the best natural defense mechanism against problematic fungal infections, enabling him to avoid copper and sulfur altogether.
On Mount Etna in Sicily, Frank Cornelissen explains that in extreme cases, the vines themselves can actually die from mildew. He says, “When the attacks are massive, then vines which are more fragile can get a ‘stroke,’ and will not recover. It is like when people die after getting the flu. It is not the flu that kills them, but the fragile immune system.”
Rajat Parr uses milk, in addition to botanicals like turmeric, nettles, and milk thistle, to combat mildew at his Phelan Farm vineyards in Cambria, California. (Photo: LITTLEWINE.)
He also tends olive trees and has been implementing additional agroforestry to further diversify his vineyard ecosystems and optimise vine health. “Planting fruit trees on the outskirts of our vineyards creates a more complex ‘terroir.’ You will therefore attract a larger variety of insects and create a more complex and thus also more protective environment. It will never do the perfect job, but it does help to reduce diseases.”
For Frank, there is no substitute for experience. With every vintage he learns and is better able to interpret the ever-changing climate. Combined with using the most high-tech farming equipment, this has enabled him to be at similar low copper levels as Domaine de l’Ecu.
However, with climate change, the future remains uncertain. He says, “I am curious and interested in hybrid vines, as they need little or no treatments. But this is a far stretch and will require lots of time to find the right variety for our area. But we have begun the research as we need to think of the future.”
Frank Cornelissen's vineyards in Mount Etna, Sicily. (Photo: LITTLEWINE.)
Hybrid grape varieties are bred from Vitis vinifera (the Eurasian grapevine responsible for the majority of the wine that we drink), and other grapevine species, typically from North America, such as Vitis labrusca and Vitis rupestris. Some of these varieties better tolerate climatic challenges and better withstand disease pressure. In the past, they suffered from an inferior reputation, but in recent years wines such as those produced by Deirdre Heekin of La Garagista in Vermont and Thomas Niedermayr in Alto Adige have been proving that these varieties can produce excellent, terroir-expressive wines.
Eduard Tscheppe and Stephanie Tscheppe-Eselböck of Gut Oggau are based in the Burgenland, Austria. While downy mildew is not such a big problem here (they only need to use around 250g of copper per hectare, if at all), powdery mildew is still a concern. They work biodynamically, using local plants such as nettle, dandelion, chamomile, horsetail, and yarrow for extracts and ferments. Additionally, they find that the horn silica biodynamic prep (501) helps to strengthen their plants.
Working with established vineyards, eventually the desire to also plant a vineyard from scratch grew too strong to ignore. In 2018, they began to lay their own roots.
Having already worked with the Austrian hybrid Rösler—which they noticed needed fewer treatments as it has a higher tolerance for mildew—they were inspired to learn more about the latest generation of hybrids, known as PIWIs. They decided to plant a mix of these, with heritage of grapes such as Grüner Veltliner, Welschriesling, Weissburgunder, and Blaufränkisch.
“We have not planted monocultural vineyards, but rather biotopes with many trees, bushes, flowering plants, vegetables, herbs… in short, creating a Garden of Eden."
-Eduard Tscheppe and Stephanie Tscheppe-Eselböck, Gut Oggau
So far, they have only needed to spray these young plots with sulfur twice a year (occasionally together with copper if very wet in spring) after which only plant-based preparations are used, whereas their regular vineyards need treatments six to eight times per year.
“We consider the PIWI grapes to be an important alternative for the future, given that plants are and will be even more challenged by climate change and an increase in extremes. If we can help them to relieve stress regarding the fungal diseases, they have more energy to thrive. Our experience with Rösler has proven to us that those grapes show an amazing sense of place if you treat them right.”
They wanted to plant with only natural and/or recyclable materials, so train the vines with the ‘StockKultur method’—on wooden poles, rather than the typical wire trellis. They also want to work solely by hand and by horse, without heavy machines to avoid soil compaction—“A healthy and active soil creates a vital environment with everything in a balanced place,” say Eduard and Stephanie—and, like Cornelissen, to promote the utmost biodiversity to increase disease resistance.
“We have not planted monocultural vineyards, but rather biotopes with many trees (120 per hectare), bushes, flowering plants, vegetables, herbs…in short creating a Garden of Eden far beyond an ordinary vineyard. The trees will attract birds to balance out the insect population, bring shade to the vines, interconnect through mychorrizae, and bring some nice fruit. The other plants are safe havens for many insects, and beehives guarantee pollination. We are working to develop a healthy ecosystem in each of the plots, to build up humus, and to create a feel-good atmosphere for the plants based on a healthy, vital soil.”
Eduard and Stephanie of Gut Oggau estimate that the work in these vineyards is around four times more time-intensive. But every minute is one spent investing in the future of a greener form of agriculture.
Eduard and Stephanie have already noticed a difference, saying, “There is even more vitality, wildlife, and energy present. Every time we are there, this extra energy gives us goosebumps, but at the same time calms us down and relaxes us. There is so much peace and strength in the vineyards.”
They estimate that the work in these vineyards is around four times more time-intensive. But every minute is one spent investing into the future of a greener form of agriculture, and every minute is worth it.
This agricultural research is a lifelong endeavour. Growers know that they may experiment for their whole lives and still not find definitive answers, but they propel newfound knowledge into the future by passing on discoveries to the next generation. It is a selfless kind of legacy; one wholeheartedly dedicated to the grapevine. As Frank Cornelissen says, “There are no difficult questions, but the answers are complex and not singular… a mix of science and sensitivity. It is more like an essay which ends with a question, instead of a Hollywood movie which ends with the perfect answer.”
Harvesting grapes at Celler Frisach. (Photo courtesy of Celler Frisach.)