“I sold Joris my SCOBY from Paris,” jokes David Toutain, executive chef of his eponymous restaurant in Paris (Two MICHELIN Stars and MICHELIN Green Star, MICHELIN Guide France 2024). “Just kidding — SCOBY is always shared because it grows and thrives when passed around, making fermentation a zero-waste process.” Chef Joris Rousseau at one-MICHELIN-Starred and Green-Starred Feuille laughs in response, “That SCOBY is the symbolic bond between Paris and Hong Kong, linking both of our kitchens together.”
This playful exchange highlights more than just their shared love of fermentation. For both chefs, it represents a philosophy that connects the earth, the community, and the ingredients. “Fermentation is about preserving the memories of the land, the people, and the stories in every ingredient,” says Toutain. “It’s my way to slow down, savour the seasons, and reduce waste.” When he first opened Feuille in Hong Kong, he made sure his team embraced the same commitment to sustainability.
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An Ancient Technique That Continues to Shine Today
Fermentation, an ancient practice rooted in both Asia and Europe, continues to be as relevant today as ever. “When we ferment, we’re giving back, reducing our impact, and creating flavours that surprise and delight,” Rousseau adds. “It’s a way to connect with the world around me that’s both creative and sustainable.”
At Feuille, fermentation plays a key role in unlocking new flavours and textures. Take their Juniper-Oyster-Shallot dish, where fermented bananas add a surprising layer of acidity similar to umami, enhancing the banana’s natural sweetness. “By preserving bananas in salt over three weeks, fermentation transforms the flavour and texture, creating a unique mouthfeel with pronounced tannins that blend seamlessly with the oyster’s brininess,” explains Rousseau.
But fermentation isn’t reserved for MICHELIN-Starred restaurant chefs — it’s something anyone can try at home. “When you ferment at home, you capture the true essence of produce, enriching its flavours with the unique depth that only time and a little microbial magic can bring,” says Toutain. “Beyond reducing food waste by extending ingredient life, it’s a way to savour the seasons all year and connect more deeply with the food on your plate.”
Ready to get things bubbling? Here are five essential fermentation techniques to kickstart your home experiments.
1. Lacto-Fermentation
Method: Chop up your favourites (cucumbers, beets, or bell peppers), pack them in a jar, and cover them with a brine made of 15-30g of salt per litre of water. Let them sit at room temperature for 3-7 days, tasting as you go until you hit that perfect sour note. At Feuille, they take fermented bell pepper to the next level, giving their Turbot-Bell Pepper-Capers creation a bold, Tabasco-like flavour that surprises guests’ taste buds.
Pairs well with: Grilled meats, creamy cheeses, and a cold beer or kombucha.
2. SCOBY (Symbiotic Culture of Bacteria and Yeast)
Method: Find a SCOBY online or from a friend. Brew a strong tea (black or green), and add 180g of sugar for every litre of tea. Once cooled, add the SCOBY and its liquid culture. Cover the jar with a cloth, then let it ferment for 10-15 days at room temperature. The SCOBY transforms the sugar into tangy, effervescent goodness. For aromatisation, like Feuille’s Chia Seed-Lemon Tree Kombucha, infuse your brew with fresh lemon tree leaves (or other herbs) from local farms to elevate the taste. Extend the fermentation for a few more days for a more sparkling kombucha but watch out for the pressure! (Right image: Jars of fermenting vegetables and fruits at Feuille.)
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Pairs well with: Fresh salads and light seafood if it’s a light, citrus-infused kombucha, or spicy dishes and rich meats if it’s a bold, fruit-infused kombucha; but best as a palate-cleansing drink on its own.
3. Kefir Culturing
Method: Add kefir grains (available online or from a friend) to milk (cow, goat, or plant-based). Let it sit at room temperature for 24-48 hours until it thickens and turns slightly tangy. Strain out the grains and refrigerate. Kefir is a probiotic-rich drink that’s perfect on its own or in smoothies.Pairs well with: Fresh fruit salads, oatmeal, grilled fish, or light meals, and makes a great companion to herbal teas.
4. Soda Fermentation
Method: Brew a sweetened base (like fruit juice or herbal tea). Add a small amount of active yeast (or leftover kombucha) and let it sit in a sealed container for 2-5 days. The yeast ferments the sugar, creating carbonation. At Feuille, Rousseau makes lychee soda by reusing lychee seeds from their seasonal dish — Lychee-Bhutan Pepper-Marigold, embracing their zero-waste philosophy.Pairs well with: Light seafood dishes, fruit-based desserts, or as a refreshing drink on its own.
5. Fermented Hot Sauces
Method: Blend fresh chilli peppers (like jalapeños or habaneros) with salt and water. Place the mixture in a jar, and let it ferment for several weeks at room temperature, stirring daily. Once fermented, blend the peppers into a smooth sauce. The fermentation process enhances the depth and complexity of the hot sauce.
Pairs well with: Tacos, grilled meats, pizza, and can add a spicy kick to cocktails like Bloody Marys, and particularly IPAs. (Left image: Fermented lychee seed soda made from byproducts of the seasonal dish, Lychee-Bhutan Pepper-Marigold)
These five fermentation techniques are just the beginning—it’s an invitation from Toutain and Rousseau to reconnect with the earth’s bounty. At Feuille, fermentation goes beyond flavour; it’s about camaraderie, sustainability, and honouring what’s local and meaningful.
As Rousseau puts it, “My goal is to share my passion for fermentation with those who are interested. I’ve learned that Hong Kong once thrived with farms, and I hope to witness a resurgence of local agriculture, reclaiming the landscape.” By embracing fermentation, we’re not only reducing waste but fostering a more sustainable, flavourful future together.
Hero image by Hei Kiu Au, Chef Toutain and chef Rousseau demonstrating fermentation techniques at an exclusive workshop at Feuille, Hong Kong.
Further Reading: Small Great Things: The MICHELIN Green Star Restaurant Championing Sustainability with a Bean
