Fermented Pastes: Gochujang, Doenjang, Miso, and How to Use Them

A fermented paste is not a seasoning but a finished ferment

Salt adds one thing. Sugar adds one thing. A paste does not. Soy protein broken down over months or years arrives with amino acids (savour), sugars (sweetness), organic acids (acidity) and salt already bound together in one substance.

So adding paste is not seasoning, it is adding another ingredient. You correct after it goes in, and if you finish the seasoning before it goes in the dish will be salty (fermentation basics, building umami).

What did the breaking down decides what the paste is like

Behind "months or years" the thing actually working is enzymes, and who made those enzymes decides the character of the finished paste.

• Miso grows a chosen koji mould on rice or soy so it will manufacture enzymes; once the salt goes in it is not the mould but the enzymes it left behind that spend the year. Picking the culture is why the result is consistent.
• Korean meju is a block of cooked beans left to catch whatever wild moulds and bacteria are in the air. Submerge that block in brine and the liquid rising off it is soy sauce while what remains is doenjang — two products from one vessel.

Same beans, same salt, a different cast doing the work. "Miso must not boil; doenjang has to", below, is the consequence — not simply a matter of how long each was fermented.

Brands differ in salt, so season last

This is the most practical item on the page. Approximate ranges:

• Gochujang — 4-7% salt, and quite sweet
• Doenjang — 10-13% salt
• Miso — 5-13% salt (white low, red high)
• Doubanjiang — 10%+, with wide variation between products

The same "two tablespoons of doenjang" can differ by 2g of salt between brands, and in a soup you taste that difference directly. So the order is always: dissolve the paste, simmer, then decide about salt (salt and seasoning).

Paste scorches

A paste carries sugars and amino acids together, which is an ideal composition for the Maillard reaction — and that also means it burns easily. Dropped straight into a hot pan it turns bitter within seconds.

Two ways to handle it.

• Slacken it in liquid first. Hold the paste in a ladle, add a little of the broth, work out the lumps, then stir it in. This is the standard method for doenjang-jjigae.
• Fry it in oil. This is deliberately courting the Maillard reaction, and the condition is low heat, briefly.

Chunjang and doubanjiang must be fried

This looks like an exception to the rule above and is a separate matter. Unfried chunjang is bitter and astringent.

Frying the black bean paste in oil to drive that astringency off is half of making jjajangmyeon. Doubanjiang is the same: frying it until the oil runs red in mapo tofu is where the aroma comes from (blooming spices).

The window is low heat, thirty seconds to a minute, until the colour deepens slightly and the smell lifts. Over high heat that window does not exist.

Huiguorou runs the same order: boiled and sliced pork belly goes into the pan, then the doubanjiang, fried until the oil runs red, and only then everything else.

But that clock belongs to one way of doing it

The two dishes above are not in the same pan. Huiguorou says almost no oil goes in — a tablespoon to start and the rest renders out of the pork — and its doubanjiang is pushed to one side of a hot wok and fried in that rendered fat for thirty seconds, which is the window exactly. Jjajangmyeon fries its chunjang in a pool of oil deep enough to suspend it, over a low flame, for two to three minutes — and that step describes nothing but the paste, so there is no other work hiding inside the number.

Both are right, and what differs is how the heat reaches the paste. Against metal it arrives at the pan's temperature at once; floating in oil it cannot get past the oil's, and a low flame under that much of it moves slowly. It is the same fact as the line above about high heat: the window is a temperature, and a clock only measures how fast you arrive at it. So the signal below is the thing to carry from dish to dish, and thirty seconds to a minute is what it comes to in a thin film of fat.

Mapo tofu and yuxiang eggplant sit between the two: the heat drops and the paste goes into a pan that already holds meat and its rendered fat, which is neither a smear nor a pool.

With a wetter paste there is a surer signal than a clock. When the oil separates back out onto the surface, enough water has left; add the liquid before that and a hard edge stays in the dish to the end (blooming spices).

Miso must not boil; doenjang has to

Two soybean ferments, opposite instructions, and the difference comes from how they are made.

• Miso is often fermented for a comparatively short time, and its aroma compounds and live enzymes are part of the flavour. Boiling drives those off. In miso soup the paste goes in after the heat is off.
• Doenjang is fermented far longer, its soy protein is more thoroughly broken down, and it needs to boil for that savour to move into the broth. A briefly simmered doenjang stew tastes shallow.

"Never boil fermented paste" is advice that is only true of miso.

And there is a dish that puts that miso over charcoal

Dengaku spreads miso on tofu and sets it over direct fire — the exact opposite of the rule above, which makes it clear what survives. The aroma fermentation produced really is destroyed. A different one is manufactured in its place.

A year of fermentation leaves miso full of free amino acids, so with sugar added and direct heat under it the Maillard reaction runs within thirty seconds. The dish does not contradict "heating miso drives its aroma off"; it lets that happen and fills the gap with something else.

Even the order follows from it: grill the tofu bare first, then spread, then thirty seconds to a minute more. Spread first and the miso is burnt before the tofu is cooked.

Sometimes the paste is not in the dish at all

Everything above assumes the paste ends up in what you eat. A family of Korean pork dishes uses it the other way round — for what it removes rather than what it adds.

Jokbal parboils the trotters for ten minutes with rice wine and a tablespoon of doenjang, then throws that water away entirely. Suyuk stirs doenjang into the water the pork boils in and serves the sliced meat; its own page puts both halves in one line — "simmering with doenjang takes the gaminess off and adds savour." Pyeonyuk does the same and then keeps that broth for a later soup, so the savour is not wasted; it simply is not in this dish.

None of the practical rules above bind in that use. There is nothing to taste and correct at the end, so the 2g of salt between brands stops mattering and a flat tablespoon is right whatever you bought. Boiling water cannot scorch a paste, so the slackening step has nothing to prevent. And "doenjang has to boil for that savour to move into the broth" still happens exactly as described — you then pour the broth away, or set it aside.

Gamjatang is where both jobs happen in one pot, in two stages: the first water goes down the sink with the blood and the scum (stocks and broths), and the doenjang goes into the second, kept broth — which is why its page says the paste "tames the pork and gives the broth its base." Doenjang-jjigae is the far end, where there is nothing to cover and the paste is the dish.

Dak-hanmari is the control, and it states the choice outright: "no salt and no doenjang go into this broth, so there is nothing to cover anything up."

Covering and removing are different jobs

Alcohol in cooking sets out the other route. The fishy and gamey notes are volatile amines, they evaporate along with the alcohol, and so the wine goes in early with the lid off — covered, it condenses and comes straight back.

A paste cannot work that way. It does not evaporate, so nothing leaves with it and the lid is beside the point. What it brings instead is a savour heavy enough to sit over what is underneath, which is the word dak-hanmari itself uses. That is why jokbal puts both into the same pot — the soju to carry the smell out, the doenjang to stand over what is left, and the discarded water to take away the rest.

Gochujang is not the heat

A common misconception with visible consequences. Gochujang is sweet, savoury and red — it is high in sugar. Most of the heat in a Korean dish comes from gochugaru, the chilli flakes (chilli and heat).

So adding more gochujang does not make a dish hotter, it makes it sweeter and thicker. Tteokbokki that is sweet but not spicy, jeyuk-bokkeum that tastes cloying — usually this. Reach for gochugaru when you want heat and gochujang when you want colour and body.

The sauces for bibimbap and golbaengi-muchim are built the same way: gochujang for the base, gochugaru to set the heat.

Cheonggukjang follows different rules

Cheonggukjang is fermented briefly — two or three days — and without salt, which makes it the outlier. With almost no salt of its own you season it separately, and its aroma compounds are heat-sensitive, so long boiling removes the very smell that defines it. Add it at the end and bring it to one boil.

That is because a bacterium made it, not a mould. Where the miso and doenjang above use enzymes a mould manufactured, here Bacillus subtilis does the work itself — which makes it the sibling of Japanese Natto, built from the same bacterium. What differs is not the cast but the conditions: wild flora off rice straw for three days, salted and mashed for use in a stew, against a pure starter for one day, eaten with nothing added.

It also explains those sticky threads. They are not a polysaccharide but poly-glutamic acid — glutamate linked into a chain (building umami).

Storage

• Press cling film onto the surface to exclude air, and refrigerate. A dry surface oxidises.
• White growth is usually yeast. Scrape it off and carry on.
• Black, red or green mould means throw it out.
• That rule is about a finished paste, not about fermentation itself. Miso and Tempeh are made by growing mould on purpose, and in tempeh the hyphae knitting the beans into one slab is the product. The difference is whether a chosen culture was put on a controlled substrate, or whether something unidentified landed on the surface of a finished paste. In the second case there is nothing to judge it by, so discarding it is correct.
• A surface darkening to brown is oxidation rather than spoilage, but the flavour in that layer has already gone.

Substitution changes the direction of the dish

• Miso for doenjang works, but the salt level and the depth of savour differ. Use slightly more and simmer it less.
• Miso + gochugaru + sugar for gochujang imitates the colour and sweetness, and only that.
• Gochujang for doubanjiang does not work. Doubanjiang is salty with a sharp fermented edge; gochujang is sweet, and the dish tips entirely toward sweetness.