Food scientists concoct delectable foie gras without force-feeding

CBC

02-04-2025

Foie gras, the luxurious French delicacy made of the fatty liver of a duck or goose, is renowned for its rich, buttery texture and decadent taste.
But it's also a dish that has sparked a lot of controversy.
Traditionally, it's made by force-feeding birds for weeks to fatten their livers, a practice that has led to foie gras being banned in several countries, including Denmark, England and Germany.
Now, scientists in Germany say they have cracked the code on how to make foie gras in a more ethical way.
A new study published in Physics of Fluids shows that it's possible to recreate the taste and texture of foie gras without the need for force-feeding.
"We are very, very confident because the mouthfeel and the taste and also the fat melting resembles very much the original product," Thomas Vilgis, a food physicist and researcher behind the study, told As It Happens host Nil Kӧksal.
"We tested in the laboratory not just only by our mouth, because this is very subjective, but we used testing machines [and] physical mechanics to test the flow properties, the melting [and] the consistency."
The challenge, he says, was figuring out how to build up the fat in the bird's liver.
What was the technique they found?
His team set out to discover what could be added to the livers in a lab setting after the birds had been butchered. They experimented with various combinations of liver, fat and collagen — ultimately discovering a technique using enzymes.
They found that when ducks or geese are force-fed, enzymes called lipases in their bodies break down fat into smaller pieces, allowing it to crystallize and form irregular clusters. These clusters, surrounded by liver proteins, create the rich flavor and texture of foie gras.
He and his team found that they could replicate this process.
The team used duck or goose fat, and injected it with an enzyme. It was then mixed with water to create an emulsion to mimic the natural digestive process in a fowl's small intestine. The treated fat is mixed with a normal duck liver, and is finished in the same manner as traditional foie gras — puréed and slightly heated.
The team also tried mixing the liver meat with plant-based fats but found they didn't work as well. Animal fats, it turns out, are essential because they can reach the right melting point to recreate the texture of traditional foie gras.
What's next?
Vilgis is so confident in the new process that he's patented it.
And he says he believes the method could change the way foie gras is made and sold.
"There is no reason to ban this product because the reason why it's banned is the force-feeding. And the force-feeding doesn't happen in this case," said Vilgis.
"It's not even chemistry; it's just purely physical and so it's just restructuring the fat and nobody can be against that just for ethical reasons."
Tianxi Yang, an assistant food science professor at the University of British Columbia who was not involved in the study, says the technique "sounds [like] an exciting and innovative approach."
Whether the enzyme-based method can fully replicate traditional foie gras will depend on consumer sensory testing, but the early results are promising, she says.
"This research aligns with a broader trend in food innovation, whether we can use novel food technology to produce traditional foods in a way that's more ethical and sustainable," said Yang.
"If this technique proves successful, both technically and commercially, it could change how we think about luxury foods, and open up some important conversations around animal welfare, authenticity and consumer acceptance."
Chef Pascal Geffroy, owner of the Toronto-based French restaurant Batifole Gourmand, says he would try it, but has doubts about quality.
Fantastic foie gras needs to have a balance between the meat and the fat, he says, and that's best done the natural way.
In France, ducks are raised outdoors and fed a variety of fodder, including corn, grain and herbs, which contribute to the exquisite quality of foie gras, a process that takes six to twelve months, according to Geffroy.
As for Vilgis, he says he hopes his team's foie gras could be available by Christmas, a time when the dish is typically enjoyed.