Whenever Euny Hong’s mother flies Korean Air, she asks for an extra tube of gochujang, the crimson fermented chile paste, for her in-flight bibimbap. Later, at restaurants, she’ll take the tube out of her purse and squeeze some gochujang onto her plate.
“It’s so embarrassing,” said Ms. Hong, a cultural critic who has written multiple books on Korean culture, including “The Birth of Korean Cool” and “The Power of Nunchi.” But recently, while talking to some friends, she learned that many other Korean mothers of a certain generation seemed to do this, too.
The thing is, gochujang — a mix of glutinous rice, fermented soybeans and gochugaru, the glorious red-pepper powder, among other additives — might be good in a pinch when you’re out and about, and in need of spice, but it’s not quite a sauce. Not in the way Sriracha or Tabasco are, anyway. It’s a jang, a foundational ingredient in Korean cooking, meaning you usually need to add other ingredients to it: Soy sauce, vinegar and garlic are common accompaniments, turning it into a sauce, glaze or marinade. (Swirled with brown sugar and butter, it also works surprisingly well in a cookie.)
But even in bibimbap, which Ms. Hong referred to as “the gateway drug to gochujang,” most recipes call for cutting the hot pepper paste with nutty sesame oil.
In its truest form, gochujang is sold as a thick paste, often in plastic tubs and glass jars, and ready for cooking. The kind labeled a sauce or condiment is the same paste, thinned out with other ingredients such as sugar and vinegar. Generally speaking, where you’re meant to cook with the jang, you’re meant to eat with the jang-based sauce.
When O’Food, a branch of the Seoul-based Daesang Corporation, released a gochujang sauce in a squeeze bottle, the company didn’t know that it would become its best-selling product.
Daesang’s gochujang sales have outpaced those of a growing slate of competitors. Scott Choi, the director of sales at Daesang America, attributes that success to a number of factors, including rising international interest in South Korean culture and a short ingredient list that highlights the paste’s essence without additives like corn syrup. “Our goal was to make a gochujang that’s untainted,” Mr. Choi said.
Gochujang is one of the youngest jangs, a sort-of sibling to doenjang (soybean paste) and ganjang (soy sauce), and all united by their layered, fermented flavors.
More than just sweet and spicy, gochujang is loaded with gamchil mat, or savoriness, the kind that makes you smack your lips. It’s the source of that unknowable depth found in dishes like tteokbokki, budae jjigae and buldak.
“Cayenne hits you more in the front, but gochujang subsides in the back and I think that’s why people really like it,” said Deuki Hong (no relation to Euny Hong), the chef and owner of the Sunday Family restaurant group in San Francisco.
That foundational flavor, Mr. Hong said, is “something that you can’t cheat, you know?”
You may not be able to cheat it, but you can iterate on it. That’s the whole point of a jang. In these garlicky, buttery noodles, for instance, honey and sherry vinegar are added to round out gochujang’s deep heat into a mellowness that’s at once sweet, savory and tangy. The brick-red butter sauce glosses and slicks, as is gochujang’s wont.
In this burbling stew, plush baby potatoes, white beans and Tuscan kale underpin a warm savoriness reminiscent of South Korean gochujang jjigae, a pantry-friendly camping staple, and dakdori tang, a dish of gochujang-braised chicken and potatoes.
But don’t let anyone, even me, tell you that you can’t eat this jang straight out of the tube.
Ms. Hong’s Korean Air story reminded me of how my father would rub a tablespoon of his mother’s homemade gochujang into a bowl of white rice when he was a little boy in 1960s Seoul. And how decades later, my mother would surprise him with a 10-year-old jar of gochujang that my grandmother had made before she died, a parcel from the past that had been carefully preserved in our basement freezer.
I watched as my father took a small spoonful of the paste and rubbed it into his rice. When he took a bite, he said he didn’t think he would ever taste that flavor again.
That’s the effect of gochujang. Once you experience it, it never really leaves you.