Most celebrity chefs attempt a commercial cash-in at some point. Titans of French cuisine, Joel Robuchon and Paul Bocuse, already had their own ranges of ready meals back in the 1980s, and since then we’ve witnessed Marco Pierre White’s evangelical zeal for stock cubes, Heston Blumenthal’s Christmas Pudding, Gordon Ramsay’s cheap Korean beer, and is there anything Jamie Oliver hasn’t endorsed?

Now it is the turn of René Redzepi, founder of Copenhagen’s fabled Noma, named the best restaurant in the world a record five times, including last year when it was also awarded its third Michelin star. But, as you would expect from the restaurant that brought us live ants as a garnish and where I was once served a deeply perplexing dessert made out of plankton, Noma’s first commercial product is rather more unusual. 

“Ferments are at the soul of every flavour we make,” Redzepi announced to the world via the Zoom launch of Noma’s Smoked Mushroom Garum last week. “We’ve used ferments for years – made from seafood, meats, vegetables, smoked, not smoked.” 

He might also have mentioned their experiments with fermented insects and reindeer penis, but what is a ‘smoked mushroom garum’? I visited the restaurant, located in a bucolic urban garden beside the city moat, to find out. 

The Romans made garum 2,000 years ago by leaving anchovies to liquify in salt; the same process is used to make Asian fish sauces to this day. But no fish are harmed in the manufacture of Noma’s vegan-friendly version. To kick-start the fermentation of the organic mushrooms they use a cultivated mould, koji, which originates in Japan where it is used to make soy sauce, miso paste, sake and other fermented products.

“We chose mushroom garum as our first product because it was something we have used for many years, and we knew we could make it here in the kitchen,” explains Thomas Frebel, Noma’s creative director, pouring a little of the sauce into a sherry glass for me to taste. In one month they processed five tonnes of mushrooms and made 600kg of their own koji rice ‘cake’ inoculated with the koji spores (having to explain to the Danish food authorities what koji actually was along the way), before leaving it for a five week fermentation, cold smoking the resulting strained liquid over birch wood.

I take a deep sniff. I’m getting… “Marmite?” I venture. Luckily Frebel laughs. “Australians here have said ‘Vegemite’.” I take a sip: it’s much smoother than Marmite, rounded, balanced, remarkably savoury, with a light smokey-umami finish which lingers like a good pho, the Vietnamese broth. One could almost drink it neat, not something you’d want to do with Maggi sauce.

Frebel explains that from the many hundreds of foods and flavours Noma has innovated over the past nearly 20 years, they initially whittled down 90 for a tasting session. Of those, the garum was chosen because, as Frebel says, “Whatever I cook with it, it just tastes of more”, it is especially good at lending vegetables a savoury heft apparently.