Kombu, or giant kelp, is the critical ingredient in Dashi - which is to Japanese cooking what chicken broth is to Americans.
Dashi is the mother stock of Japanese cooking. It’s made by boiling seaweed and dried fish together briefly and straining, which creates a light, savory stock.
Actually, although dried fish has been used for centuries, that's largely because Japanese didn't have access to dietary meat for much of that time - you can obtain an identical stock using the kelp with shaved pork, for example. And the kelp is essential because it's uniquely high in glutamic acid, which is what imparts that savory taste to Dashi.
Kombu seaweed, it turns out, has one of the highest concentrations of naturally occurring glutamic acid of any food — it’s made of 1.6% free glutamic acid by weight.
What happens when you take ions of glutamic acid and bond them with sodium ions? You get a stable salt. A killer flavor enhancer. And a much-maligned one. It's called monosodium glutamate. MSG. That's bad, because it's a chemical. "Naturally evaporated" Dashi, or Kombu salt, is exactly the same stuff, but it's good - because it's "natural".
“I think there is a class of people who understand that synthetic versus natural is a very arbitrary boundary that falls apart under scrutiny.”
The chemical, glutamic acid, is the same, whether it is created by fermentation in a factory or in the R&D lab of Momofuku. The question for Chang comes down to why the stuff called MSG is demonized, and the “natural” evaporated kombu salt is considered gourmet.
“The funny thing is that I can make some stupid fucking hipster dish with Dorito powder and serve it on roasted corn with fucking lime juice and people would eat the shit out of it,” Chang says. “If I say, ‘That’s got MSG in it,’ no one’s going to say, ‘Well, that sounds delicious.’ But if I put Doritos on it…for fuck’s sake, Taco Bell’s marketing it directly.”
The chef's words - not mine. But you get his point.