How humanity learned not only to recognize umami, but to release it, deepen it, preserve it, and build culture around it.
The Umami Odyssey Continues
In Part 1 of The Umami Odyssey, I began with a biological question: Why do we crave umami at all?
The answer led backward, toward survival. Long before cuisine became culture, taste was information. Sweetness suggested energy. Salt pointed toward minerals. Bitterness could warn of danger. Sourness could signal ripeness, fermentation, or decay. And umami helped the body recognize amino-acid-rich nourishment.
That was the first chapter of the story.
But once we see umami as an ancient biological signal, another question becomes unavoidable:
What did human beings learn to do with that signal?
We did not simply keep eating the foods nature gave us. We salted them, dried them, crushed them, mixed them, packed them into vessels, buried them, stored them, and—most importantly—waited.
Out of that waiting came soy sauce, doenjang, fish sauce, cheese, miso, gochujang, kimchi, and thousands of other fermented foods across the world.
Evolution taught us to recognize umami. Fermentation taught us what to do with it.
If Part 1 was about umami as a language of survival, Part 2 is about the moment that biological language became human technique—and eventually culture.
Read The Umami Odyssey: Part 1 — The Language of Survival
Umami Is Not the Same Thing as Deliciousness
Before talking about fermentation, one distinction matters.
We often use the word taste for everything that happens when food enters the mouth. But what we experience as flavor is much larger than the tongue alone.
The tongue detects basic tastes such as sweet, salty, sour, bitter, and umami. The nose reads volatile aromas. Chili heat is largely a trigeminal sensation rather than a basic taste. Texture, temperature, viscosity, crunch, tenderness, and even sound all influence what the brain finally understands as flavor.
This matters because fermentation does not simply “make more umami.” That explanation is too small.
Fermentation can create acidity, transform aroma, soften texture, generate bitter or sweet compounds, break proteins into peptides and free amino acids, and produce compounds that influence mouthfulness, continuity, and lingering richness. Some of those changes involve umami. Many do not.
So the first principle of this chapter is simple:
Fermentation is not umami. Fermentation reorganizes flavor, and umami is one important part of that transformation.
Fermentation Does Not Create Flavor from Nothing
A soybean already contains protein. Cabbage already contains carbohydrates. Fish already contains amino acids, nucleotides, fats, and minerals.
Fermentation does not invent these materials. It changes their form and their relationships.
Large proteins can be broken into smaller peptides and free amino acids. Carbohydrates can be converted into organic acids, alcohol, carbon dioxide, and other metabolites. Fats can be transformed into molecules with entirely different aromas.
This is why I have come to think of fermentation less as “making flavor” and more as releasing flavor potential.
The raw material contains possibilities. Microorganisms and enzymes unlock them. Salt shapes the environment. Temperature changes the pace. Time allows the reactions to continue.
Fermentation is not another ingredient added to food. It is a process that changes what the ingredients are capable of becoming.
But Waiting Is Not the Same as Fermenting
One of the most useful examples on K-TASTE is surprisingly not a fermented food at all.
Sikhye: When Starch Becomes Sweet
Look again at traditional sikhye, Korean sweet rice punch. Malted barley is soaked. The liquid is combined with cooked rice. The mixture is kept warm. Then we wait.
After several hours, rice grains begin to float and the liquid becomes sweet.
The process looks remarkably like fermentation, and traditional cooking language often treats it that way. But the central reaction is different.
Sikhye is primarily a story of saccharification.
Amylase enzymes from malted barley cut large starch molecules in cooked rice into smaller sugars. The sweetness was already chemically possible inside the starch; the enzymes simply made it accessible to our senses.
This distinction changed the way I began to think about traditional food.
Time is not the cause. What matters is what is acting during that time.
In sikhye, enzymes do most of the work. In kimchi, microbial communities transform sugars and produce acids and other metabolites. In cheonggukjang, microbial enzymes aggressively break soybean proteins apart.
Different foods can all require patience while relying on completely different chemistry.
And this may be one of the most remarkable things about old kitchens: our ancestors did not know the word amylase, but they knew when the rice floated. They knew the temperature by touch. They knew how long to wait.
Science eventually named the mechanism. The kitchen had already learned the behavior.
K-TASTE FOOD CONNECTION
Master the Art of Floating Rice Grain Sikhye
Cheonggukjang: When Protein Becomes Taste
If sikhye helps us understand what fermentation is not, cheonggukjang helps us understand what fermentation can do to protein.
Soybeans are rich in protein. But protein itself is not the same thing as umami.
During cheonggukjang fermentation, microorganisms associated with Bacillus species produce powerful proteolytic enzymes. Those enzymes begin cutting large soybean proteins into smaller peptides and free amino acids.
Among those amino acids is glutamic acid, one of the central compounds associated with umami perception.
This is where the phrase “fermentation brings out flavor” stops being mystical.
The original soybean has not disappeared. It has been translated.
The aroma changes. The texture changes. The amino-acid profile changes. The entire flavor architecture changes.
When we describe cheonggukjang as deep, nutty, savory, or rich in umami, we are not describing a single molecule. We are describing the sensory consequence of a much larger biological transformation.
K-TASTE FOOD CONNECTION
Cheonggukjang Stew with Tofu
Gochujang Taught Me Not to Use “Umami” Too Casually
Gochujang is also fermented, but it teaches a different lesson.
In the K-TASTE story about traditional gochujang, there is a line I still like:
It has spent time becoming itself.
That is closer to the truth of gochujang than calling it simply a spicy sauce.
Gochujang brings together chili, grain, fermented soybean components, salt, enzymes, microorganisms, and time. Its flavor contains sweetness, heat, saltiness, acidity, aroma, and savory compounds formed and transformed during fermentation and maturation.
There are amino acids associated with umami in that system. But deep flavor and umami synergy are not the same thing.
A food can be extraordinarily complex without every part of that complexity being umami. It can feel deep because of aroma, acidity, sugars, peptides, viscosity, fermentation-derived volatiles, and the way those sensations arrive together.
So I would describe gochujang as a powerful example of fermented savory depth.
Synergy is something more specific.
K-TASTE FOOD CONNECTION
What Is Gochujang? From Sunchang Autumns to the Taste of Home
Umami Synergy Is Not a Metaphor
Glutamate is one of the key molecules associated with umami. Certain 5′-ribonucleotides, including IMP and GMP, can also strongly influence umami perception.
The remarkable part is what happens when they meet.
Glutamate together with IMP or GMP can produce a much stronger umami response than either produces alone. This is the phenomenon we call umami synergy.
It is not simply a poetic way of saying that two tasty ingredients taste good together. It is a measurable sensory interaction tied to the way the umami receptor responds.
This changes how we should think about cooking.
Fermentation may release or increase certain taste-active amino acids. Another ingredient may provide nucleotide-based umami. When those ingredients meet, the sensory result can become greater than the sum of the parts.
This is why combinations such as kombu and bonito are so powerful, why mushrooms and meat often feel unusually complete, and why fermented seasonings work so well with broths.
Fermentation creates possibilities. Synergy changes what happens when those possibilities meet.
The World Discovered Fermentation Many Times
No single civilization owns fermentation.
People separated by oceans and centuries discovered similar principles with completely different ingredients.
Milk became yogurt and cheese. Cabbage became sauerkraut. Fish became nước mắm in Vietnam and nam pla in Thailand. Soybeans became miso and soy sauce in Japan, and tempeh in Indonesia. Rice and pulses became idli and dosa in India.
In Korea, fish and shrimp became jeotgal. Soybeans became doenjang, ganjang, and cheonggukjang. Chili, grain, soy, and salt became gochujang. Vegetables became kimchi.
The organisms differed. The climates differed. The raw materials differed. Yet the human strategy was remarkably consistent.
We learned to create conditions—and then let biology continue the work.
That distinction matters.
Fermentation is not total control. It is controlled cooperation.
Human beings choose the salt, the vessel, the temperature, the season, and the raw material. Then another world begins working inside the food.
Kimchi Is Where Several Worlds Meet
This is why I keep returning to kimchi.
Not because kimchi contains more glutamate than every other fermented food. Not because it can be scientifically crowned the “healthiest fermented food in the world.” Those claims are too easy and too careless.
Kimchi interests me because of its structure.
Look at a traditional napa cabbage kimchi.
There is cabbage, salt, garlic, ginger, green onion, chili, and often rice paste. In the K-TASTE baechu kimchi recipe, there are also fermented seafood ingredients: anchovy fish sauce and salted shrimp.
Several culinary histories enter the same vessel.
A plant substrate. Fermented marine ingredients. Aromatic vegetables. Salt. A microbial ecosystem.
Then the whole mixture ferments again.
This is more complicated than saying, “Cabbage is fermented by lactic acid bacteria.” That statement is true, but incomplete.
Kimchi is a system in which plant sugars, seafood-derived compounds, organic acids, amino acids, aromatic molecules, salt concentration, microbial succession, temperature, and time influence one another.
The choice of jeotgal does not simply add “fish flavor.” It can change the chemical and microbial environment of the fermentation itself.
That is a much more interesting idea.
K-TASTE FOOD CONNECTION
Mastering Authentic Baechu Kimchi
Kimchi Is Not Just Umami
When we bite into well-fermented kimchi, we are not tasting one thing.
We taste acidity, salt, umami, a trace of sweetness, chili heat, garlic and green-onion pungency, fermentation aromas, and the changing texture of the cabbage.
The brain combines these separate signals into one experience.
That may be why the Korean expression “jal igeotda” — “it has ripened well” feels more accurate than any single chemical description.
We do not say, “The glutamate level is correct.”
We say, “It is well ripened.”
That phrase describes balance.
The acid no longer feels separate. The garlic no longer feels raw. The salt no longer sits on top. The seafood seasoning no longer tastes like something that was merely added. The cabbage has changed without losing its identity.
The parts still exist, but they now belong to the same flavor.
That is chemistry experienced as harmony.
And Then Kimchi Goes Back into the Kitchen
What makes kimchi even more interesting is that fermentation is not the end of its story.
Kimchi becomes an ingredient.
It enters fried rice, pancakes, stews, braises, noodles, and dumplings. It meets pork, tuna, anchovy broth, tofu, rice, eggs, fat, and heat.
A fermented food that already carries its own complex taste system enters a second cooking system and forms new relationships.
For me, one of the clearest examples on K-TASTE is tuna kimchi jjigae.
Kimchi Jjigae: Where Fermentation Meets Synergy
The K-TASTE recipe combines well-fermented kimchi, kimchi liquid, anchovy broth, tuna, and tofu.
The kimchi has already been transformed by fermentation. Its acids, free amino acids, aromas, and other metabolites are products of time.
Then fish enters the equation.
Fish and meat can contain nucleotide-based taste compounds such as IMP. Glutamate and IMP are one of the classic pairings behind umami synergy.
So a stew containing fermented kimchi and fish-derived ingredients becomes a useful culinary model for understanding the principle.
I use the word model deliberately.
We have not taken a bowl of K-TASTE kimchi jjigae into a laboratory and measured every molecule. We should not pretend we have. The exact concentrations depend on the kimchi, the broth, the fish, storage conditions, preparation, and many other variables.
But the structure of the recipe reflects the same logic:
Fermentation has already changed the taste-active compounds in one ingredient, and cooking brings those compounds into contact with another source of umami.
That is the bridge between fermentation and synergy.
K-TASTE FOOD CONNECTION
Daebak Mat-Jib Style Kimchi Jjigae
So Is Kimchi the “Peak” of Fermentation?
I would use that phrase carefully.
Not as a ranking. Not as nationalism. Not as a claim that kimchi contains more nutrients, probiotics, or glutamate than every other fermented food.
I mean something else.
Kimchi is one of the clearest foods I know for seeing multiple dimensions of fermentation at once: plant material, fermented seafood, microbial succession, acid production, amino-acid change, aromatic vegetables, salt as ecological control, temperature, and time.
And after fermentation, kimchi gains an entire second life in cooking.
In that sense, kimchi is not merely the endpoint of fermentation.
It is a fermented platform for future flavor.
It arrives at the table already transformed, yet still ready to enter new relationships.
Fermentation Is a Form of Memory
There is another reason this subject matters beyond chemistry.
Fermentation stores time.
Fresh food belongs mostly to the present. Fermented food carries a past inside it.
The day soybeans became cheonggukjang. The weeks a gochujang jar sat through changing weather. The moment salted shrimp was packed away. The cold autumn day a family made kimchi for winter.
Microorganisms leave no written diary. But their activity remains in flavor.
Perhaps this is why we so often describe fermented foods as deep.
If depth simply meant intensity, heavily salted food would always taste deep. It does not.
Depth seems to involve layers, reactions, and something that happened before the moment of eating.
Perhaps what we call depth is, in part, time made sensory.
Kimjang: When Fermentation Becomes a Social Technology
Kimchi also reveals something chemistry alone cannot explain.
Kimjang is not only about changing cabbage.
Salt is prepared. Seafood is preserved. Chili is dried. Vegetables are harvested. Families and neighbors gather before winter.
The food being made today is intended to become something different after the work is finished.
Most cooking tries to complete a dish before it is served. Fermentation asks us to begin a dish and then allow time to become part of the recipe.
The cook eventually stops cooking.
Biology continues.
That changes the role of the cook. The human does not finish the food alone. We prepare the conditions, then trust a process we can influence but never completely command.
That is why fermentation feels less like domination of nature and more like a negotiation with it.
From a Language of Survival to a Language of Relationship
Part 1 began with biology.
Why does umami exist? Why does the human body respond to glutamate and other signals associated with nourishment?
The answer led us to survival.
But survival was only the beginning of cuisine.
Human beings learned to manipulate the conditions around that ancient sensory signal.
We discovered enzymes without knowing their names. We cultivated microorganisms before we could see them. We broke proteins apart, converted starches to sugars, turned sugars into acids and alcohol, released amino acids, and combined them with other sources of umami.
Then we repeated the successful patterns.
A technique became a recipe.
A recipe became a tradition.
A tradition became culture.
That is why Part 2 is not simply a story about fermented foods.
It is a story about what human beings did with umami after evolution gave us the ability to recognize it.
Fermentation expanded the vocabulary.
Synergy expanded the intensity.
Culture gave those discoveries memory.
Part 1 asked:
Why do we crave umami?
Part 2 asks:
What did humanity learn to do with that craving?
We learned to wait.
We learned to transform.
We learned to combine.
And perhaps most importantly, we learned that some of the deepest flavors do not come from forcing ingredients to become something else.
They come from creating the right conditions and allowing relationships to form.
Between protein and enzyme.
Between sugar and microorganism.
Between glutamate and nucleotide.
Between land and sea.
Between the cook and time.
Between one generation and the next.
Fermentation is the point at which an ancient biological signal becomes a human cultural technology.
And when the right molecules, ingredients, and traditions meet, that signal becomes something larger than umami alone.
Depth. Memory. Relationship.
Continue The Umami Odyssey
Part 1 — The Language of Survival: Why We Crave Umami
Before fermentation deepened umami, the human body first had to learn how to recognize it.
Read The Umami Odyssey: Part 1
Explore the Idea Through K-TASTE
Sikhye — where starch becomes sugar, but fermentation is not yet the story.
Cheonggukjang — where soybean protein begins to become taste.
Gochujang — where chili, grain, soybean fermentation, and time become a single flavor system.
Baechu Kimchi — where plant fermentation and fermented seafood enter the same ecosystem.
Tuna Kimchi Jjigae — where fermentation enters a second life and becomes a model for umami synergy.