Périgord walnut oil

Romain and Adrien Castagné represent the sixth generation of nuciculturists at Martel. Before them, Gaspard, the great-grandfather, André, the grandfather - who knew organic production - and then Jean-Luc, their father, who applied conventional cultivation like most growers of his generation. In 2018, Romain and Adrien, who have always had a foot in the farm, decided to take over from their parents. Adrien, a graduate of the Lycée Technique Hôtelier in La Rochelle, worked for a long time in a wine bar before opening his own bistro in Martel and planting vines (pinot noir, ugni blanc, syrah, chenin, roussanne, chardonnay and malbec) at an altitude of 300 meters. Romain, who holds a Master's degree in law, economics and agricultural and agri-food management, joined the Lidl chain as a network manager before moving to Nestlé as a supermarket salesman.

In the walnut industry, the equation is simple: 5 kilos of whole walnuts yield 2 kilos of kernels, which produce 1 liter of oil. However, patience is required, as it takes seven years for a walnut tree to bear its first fruit. At Castagné, 80% of the trees, planted every 10 meters on 47 hectares, are just over 30 years old. Varieties include Marbot, Corne and Franquette, authorized in the Noix du Périgord appellation specifications. For the conversion to organic farming, Romain and Adrien changed the way they managed the orchard. No more phytosanitary treatments, instead, crushed garlic macerated in vegetable oil is sprayed on the trees to get rid of the codling moth, a butterfly whose larva attacks young shoots and fruit. As for the ewes, Caussenardes des Garrigues, they are invited to clean the plots in July and August.

At harvest time, in the heart of autumn, it's all hands on deck at Castagné, family and employees alike. A little way from the mill, a building houses the various stages involved in washing, drying, grading and storing the 100 tons of walnuts. This tangle of wood, carpets, pipes and ladders is the work of Jean-Luc, who mechanized everything. First, the walnuts pass through a washing machine, before heading for the stone-cutting machine to remove the last clumps of earth and small stones. The walnuts are then rinsed, cleaned once more and sorted, as not all walnuts end up the same way. Nuts smaller than 28 - the caliber corresponds to the size of the nut - and 28/30 are used to produce oil. The 32 and over will be sold as dried nuts, some directly to the mill and the rest to the cooperative. After spending twenty-four hours in the drying towers, the walnuts descend, crossing those that have risen. They are then sorted again on a conveyor belt. Nuts that don't make the grade, and those with broken shells, are blown away, but they are not lost: they go into the oil circuit. In the end, of the 100 tonnes collected, 70% are sold as dry walnuts and 30% are transformed into oil, the equivalent of 15,000 25 and 50 centilitre bottles.

Back to the mill

In what was once a 15th-century hunting lodge, the millstone, the press and the frying pan in front of which Romain works take center stage. Every day, he produces 200 liters of oil, one fruity, one balanced and one medium. Gently, the imposing granite millstone crushes the kernels for 20 to 30 minutes. The resulting paste is then heated in the frying pan, where it is baked and roasted at between 85 and 95°C. The wood used to fuel the fire comes from walnut trees, and the walnut shells come from the enoisage process. Once roasted, the 30 kilos of dough are placed in molds, then inserted into the press. at 120 bars of pressure, the walnut oil flows out, with an incredible sweetness and aroma. It takes between 20 and 30 minutes for the paste to yield all this liquid raw material. Decanted for 3 weeks, the oil is then bottled and sold in the store next to the mill, in various distribution channels and to a number of renowned chefs. As for the pressed oil cakes, they are lightly crushed and used as feed for the ewes. Nothing goes to waste with walnuts.