Why the walnut matters more than we think.
From orchard to plate, the humble walnut opens a window onto some of today’s most pressing questions about food, health, and the environment.
Hortense de Castries, steward of her family’s orchard and founder of nOk, brings a perspective rooted in sustainable cultivation, local production, and traceability. Teresa Fernández-Gil, trained pharmacist and nutrition expert, will explore how walnuts contribute to human wellbeing and what they reveal about our relationship with food. Meanwhile, chef Isabelle Arpin demonstrates how culinary creativity can elevate this simple nut, transforming it into flavours that engage the senses and the imagination.
This conversation moderated by Christine Ferniot brings together perspectives from the orchard, the kitchen, and health. Participants will discover how the cultivation of walnuts shapes local ecosystems, how their nutritional profile interacts with human wellbeing, and how culinary imagination transforms a simple ingredient into something more than the sum of its parts.
More than a discussion of food, it is an inquiry into the practices, ethics, and pleasures that define how we relate to what we eat.
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Originally from Anjou, Hortense de Castries took over a family walnut orchard in 2018, alongside her mother. The trees were planted by her grandfather in the 1970s.
A graduate of EDHEC Business School, she initially worked in catering and agriculture, notably in the United Kingdom and Morocco, before devoting herself fully to the walnut industry.
In 2021, she founded nOk, a committed brand that promotes local, organic and fair trade walnuts produced in France and Belgium. Her ‘from walnut to finished product’ approach guarantees traceability, freshness and short supply chains.
She is also the author of the book La noix : 101 recettes – 4 saisons (Éditions Racine) and winner of the Épicures 2023 and 2025 awards. Through her work, Hortense de Castries aims to restore the walnut to its former glory, combining terroir, innovation and sustainability.
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Isabelle Arpin is a chef with a singular and unconventional path. A graduate in economics, she discovered cooking later in life—a revelation that became a vocation. Curious, cultured, and free-spirited, she learned from the best while following her own rhythm. That freedom has since defined her career and culinary signature.
Twice awarded Michelin stars (2017, 2019), Arpin gained acclaim in Belgium and abroad, yet she remains independent and deeply committed to solidarity. During the pandemic, she devoted herself to supporting healthcare workers, the homeless, and numerous social causes.
In 2023, she moved her practice to the Château de Leignon, where she is creating a space rooted in sustainability and aligned with the UN’s Sustainable Development Goals. An advocate of responsible fishing and ambassador for the UN’s Zero Waste Day in Brussels, she also advises FoodTech start-ups on plant-based innovation and sustainable agriculture.
