In the Middle Ages, the dyers blue, a natural pigment extracted from pastel, made the fortune of Picardy traders. “With this wealth, they financed the construction of Amiens Cathedral”, explains Aurore Cottrel. Four centuries later, the organic farmer from Salouël, near Amiens (Somme), tries to revive the cultivation of this cruciferous tree known as “la Waide” in Picardy or “Vouède” in Normandy. “The culture of pastel had been abandoned at the end of the XVIe century because of competition from indigo from the Far East. ” Today, synthetic indigo (80,000 tonnes per year) reigns supreme.
But the demand for natural dyes, produced locally, is making a strong comeback. In the textile industry (flax) or in hairdressing (hair dye) but also in cosmetics (oil and cream), pharmacy (active ingredients) and even gastronomy (food coloring).
Blue pigment extracted from green leaves. © Ouest-France
Aurore Cottrel has been supplying the famous Amiens blue to the Savonnerie des Hauts-de-France for three years. From 2 and a half hectares (out of 130 ha) of cultivation, its artisanal production (extraction is done in basins!) Could soon go on an industrial scale. This is the goal of Arnaud Besnier, manager of agricultural works (AGB) and cereal companies in Villers-sur-Mer (Calvados).
The two farmers, Picard and Norman, are associated in a project called “Blue and pastel, the blue dream”, recent Norman winner of the bioeconomy trophies of the Ministry of Agriculture and on track for a national trophy at the end of the month of April.
Aurore and Arnaud, who met during a “entrepreneurship and success” training session at the CER, are preparing to file a patent and raise funds to set up an extraction unit in Calvados. “Extract blue gold from the green leaf of pastel, no one has yet done it on an industrial scale”, summarizes Aurore.
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Indigotin is found in pastel leaves and, in higher concentrations, in the indigo tree. © Ouest-France
A biennial plant
No technical route, either, to cultivate the crucifer. ” After the closure of the Cagny sugar refinery (Calvados) in 2020, I had to stop beets. I tested the pastel on one hectare. It is also a good crop head. No fungicide, no insecticide. I only spent one weeding “, says Arnaud Besnier, who sells compost from waste crushing, wood chips for boiler rooms and cultivates, with his brother Guillaume, 270 ha of cereals, rapeseed, alfalfa but also grass (sold in rolls).
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The green leaf is harvested the first year. The seeds the second year. © Ouest-France
“With pastel, you learn by walking… I sowed a little early, the plant went to seeds in the first year. “ A biennial plant, pastel is sown at the end of August before being mowed (up to four cuts) from May to September. “ The first year, the leaves are harvested to extract the pigment (enough to color the jeans). The second year, we collect the seeds in order to reseed and we extract the oil that will be used in the cosmetics industry. “
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Extraction by oxidation of the greenish juice. © Ouest-France
The expected returns are still approximate. “We start with a harvest of 40 tonnes of leaves per hectare. And a ton of foil gives a little over 2 kg of pigment. Or 80 to 100 kg per hectare. “
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Pastel field in bloom © Ouest-France
To supply the extraction plant, the two partners are counting on a hundred hectares of pastel within five years. It remains to convince future cooperative members. “Pastels are much more profitable than wheat. We hope to convince cereal growers to get started and set up a cooperative. “
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