"Leaf to Root" in Graz: where celery root and carrot greens shine

"Leaf to Root" in Graz: How Wankerl utilizes every part of the vegetable

What ends up as kitchen waste elsewhere is still used in the Gerüchteküche. Top chef Michael Wankerl consistently follows the "leaf to root" principle here, which means he cooks everything: from the root to the fruit and blossom to the leaf. He doesn't peel anything and if he does, he uses the peel. Celery roots, carrot greens and parsnip peel therefore end up on the plate, as do fermented sauces and miso pastes made from regional ingredients. He also pickles and ferments food. "It's not quite the same thing," he says. "You can pickle in different liquids. Fermenting is always controlled rotting." He laughs. "Or in other words: a fermentation process based on lactic acid." Sustainable cooking doesn't mean doing without, but creativity and taste.

Why is "Leaf to Root" processing worthwhile?

The holistic utilization of plants is not only sustainable, but also economical, as it reduces food waste. "I could buy carrots in a plastic bag for €1, but I buy them open at the market for €1.50. But the greens are still on them and I use them to make pesto," says Michael.

"Of course, this way of cooking is more expensive at first glance, but I want to be creative," says Wankerl. He has adapted his way of cooking to his convictions. The impetus for the change came from his family: "My wife was involved in sustainability in the construction industry and my stepson needed 5,000 to 6,000 calories a day as a competitive swimmer. As a result, I took a close look at healthy and sustainable nutrition and realized that I had to change something." Today, sustainability is not just an attitude for him, he also enjoys it: "I still really enjoy working like this."

One tuber, many flavors: a taste journey with vegetables

The head of the Gerüchteküche dries celeriac, roasts it in the oven or serves it raw and sliced wafer-thin. "The bulb, not the stalks," he emphasizes. "It has an intrinsic saltiness and tastes so strong that further seasoning is not absolutely necessary." Wankerl's bookshelf is filled with thick tomes full of formulas and amino acid compositions. To get the maximum flavor out of a tuber, he studies cooking and fermentation processes and experiments with temperature, for example to change the sugar content and thus the taste experience and texture. Wankerl also loves roots, especially the bulbous cistus. "It looks like maggots and tastes a bit like oat root. You can fry them or eat them raw."

Seasonal and innovative: creations in the Gerüchteküche

At Wankerl, every food is only available when it is ripe in the region, or canned months later. Umeboshi, a salted, dried and then rehydrated plum from Asian cuisine, is something he created himself. "It tastes sweet, sour, salty and umami." Umami, borrowed from Japanese, means something like "delicious" and is a separate flavor that can be described as "spicy" or "meaty". Wankerl is currently trying his hand at his own soy sauce. He also makes his own miso pastes. "They need at least three months. We make them from buckwheat and emmer, but also from lentils or scarlet runner beans." He then uses the pastes for seasoning. "We use 80% plant-based products. The miso pastes are very good at teasing out the different flavors from the individual vegetables."

Respect for the animal through "nose to tail" processing

Around 20% of Michael Wankerl's cuisine consists of animal products - mostly milk, yogurt or eggs from regional organic farms. He makes no compromises when it comes to meat and consistently follows the "nose to tail" principle. "When my farmer slaughters a cow, I take half the animal," he explains. "I always leave the fillet and roast beef, they're not interesting to me. There's no idea, no character in them." Instead, the shoulder, cheek, heart, liver or lungs end up in the rumor kitchen - braised, full of flavour and without any waste. Wankerl even uses cockscombs. "They take on the taste of the sauce and have a funny texture, a bit like calamari." He provocatively serves them jagged on the plate. "My regulars then laugh and say: 'Oh look, it's dragons again today'."

Foraging: Wild delights from the forest and garden

Michael Wankerl is out in the forest with his wife almost every weekend. "We collect herbs, wild garlic, spruce shoots, capers and dig up wood sorrel roots and evening primrose roots. Everything is then freshly processed or pickled." When he's not foraging himself, two guests always bring him mushrooms or plants. "There are around 2,000 edible plant species here in Austria," he explains. "Most people don't even know what treasures are growing right on their doorstep." He even tries unknown leaves or herbs with curiosity. "My wife always says I'll die of something poisonous at some point because I taste everything," he says with a laugh. But his courage is infectious: Guests start to become more aware of nature and are delighted with the dishes that result.

How does METRO support restaurateurs, including with sustainability issues?

What Michael Wankerl can't collect himself or buy regionally from farmers, he sources through METRO - with the support of a customer manager who understands his philosophy. "When I ask for something, he usually already knows what I intend to do with it," says Wankerl. This trust saves time and enables solutions that support his sustainable cuisine. In addition, digital tools for table reservations such as DISH Reservation and DISH Order for the out-of-home business make everyday life easier. "Online reservations have reduced my phone calls by 90%. Now guests can also book at night and I have more peace and quiet in the kitchen when I'm cooking." One highlight of the reservation tool for Wankerl is the flexible dwell time. "Guests stay shorter at lunchtime and longer in the evening, now I can set this precisely." This allows him to plan more precisely, increase capacity utilization and boost his turnover.

For Michael Wankerl, wholesale and sustainability are not mutually exclusive. "Communication is important, then everything works!", he says and calls for more transparency, for example through mandatory origin labeling in restaurants. The issue of hygiene remains more difficult, where sustainable alternatives are still lacking. "I would like to see a rethink and sometimes compromises." For restaurateurs who also want to pay attention to sustainability in their kitchens, METRO offers support as part of the 'My sustainable restaurant' initiative. It provides practical tips on energy efficiency, waste management and packaging.