The Chairman - wok hei fried rice tease
CNN  — 

Chef Kwok Keung Tung tosses the wok with one hand, using the other to stir with a metal spatula.

Both hands occupied, he uses his knee to nudge the gas stove’s lever up and down to control the fire fan, sporadically engulfing a third of the wok in flames.

It takes only three minutes for the lump of white rice to transform into the bowl of golden fried rice he places on the serving counter.

“This is what you’re looking for – wok hei (the breath of wok),” Danny Yip, co-founder of Hong Kong restaurant The Chairman, tells CNN Travel.

“Wok is the essence of Chinese cooking in South China. And Cantonese chefs are the master of fire and wok.”

Wok hei: An invisible but essential ingredient in Cantonese cooking.

If anyone’s an authority on the subject of wok hei, it’s Yip.

The Chairman has just been named the no.1 restaurant in Asia in 2021 and it is the highest-ranking Chinese restaurant on the World’s 50 Best Restaurant 2019 list (there was no 2020 list due to the pandemic).

For those who grew up in a Cantonese family, it’s almost impossible to go to a Chinese restaurant without hearing someone – usually older – comment “gau wok hei” (enough wok hei) or “ng gau wok hei” (not enough wok hei) when establishing a benchmark of how authentic a Chinese restaurant actually is.

Hei (also Romanized as “hay”) is the Cantonese word for “chi,” meaning energy flow. It was once a hard-to-explain and largely ethereal concept mostly popular in the South China region. In other parts of China or Asia, even though they used woks, they didn’t focus on wok hei.

It wasn’t until the legendary American Chinese food writer Grace Young coined it poetically as “the breath of a wok” in her book “The Wisdom of the Chinese Kitchen: Classic Family Recipes for Celebration and Healing” in the 1990s that the concept of wok hei was introduced officially to international audiences.

“Wok hei is not simply hot food; it’s that elusive seared taste that only lasts for a minute or two,” Young wrote.

In other words, it’s a combination of that steaming aroma you breathe in and the almost-burning sensation on your tongue that somehow enhances the flavors of the dish.

How a wok works

In recent years, an increasing number of food writers and scientists have been modernizing Chinese cooking while looking deeper into its origins, including wok hei.

After realizing how little scientific research has been done on Chinese cuisine, Hung-tang Ko, doctoral student at the Georgia Institute of Technology, co-published a research paper titled “The physics of tossing fried rice” with David Hu – a scientist most famous for his studies on fire ants and an Ig Nobel Prize-winning investigation into why wombats have cube-shaped poop.

“Wok hei and the Maillard reaction require high heat. The commercial Chinese stoves have a mind-blowing amount of heat coming out of them,” explains Ko, who spent months studying how and why chefs toss fried rice with a wok, while also simulating rice trajectories.

The Maillard reaction is a chemical interaction that occurs between amino acids and reducing sugars in food placed under high heat. It causes foods to brown and releases aroma and flavors.