日本語版

Bitter crossing — 2026-09-06

Egumi-bitter

えぐ苦い (egunigai) — our coined term; egumi is a Japanese sensory term

Egu-bitter is NIGAMI LAB's coined term for a taste state in which egumi and bitterness are present at the same time, as separate sensations.

What this page establishes

• The term "egu-bitter" is a name NIGAMI LAB gives to cases where egumi and bitterness both remain without canceling each other out; it has not been confirmed as a dictionary headword.
• In an experiment that separated spinach extract with water and ethanol, oxalate taste and bitterness have been confirmed to concentrate in separate fractions.
• In soy sauce, a study comparing 12 brands has confirmed that egumi is bundled with astringency rather than bitterness into a single evaluation item.
• Whether egumi is placed next to bitterness or next to astringency differs by food, and a common yardstick has not yet been established.

How it arises

The evidence supporting egu-bitter has not yet accumulated at the psychophysical (solution) or receptor (cell) layer. What can be placed here is only research conducted on actual foods.

In dishes

A study on spinach passed water-extracted components through an adsorbent, separating them into two groups with different properties. What the study operationally defined as "oxalate taste" — a sensation long discussed as a cause of egumi — concentrated on the side that eluted with water, while bitterness concentrated on the side subsequently eluted with ethanol. Within the same spinach extract, the two sensations appear separated into different fractions.

The same study's conclusion goes further. Having quantified the oxalic acid in the separated fractions and cross-checked it against the sensory evaluations of oxalate taste and bitterness respectively, the authors interpreted the bitter side as not being oxalic acid itself. This reading holds that oxalate taste and bitterness — two unpleasant aftertastes — also have chemically distinct carriers.

A study on soy sauce shows the opposite treatment. When trained assessors scored 12 commercial soy sauce brands, astringency and egumi were bundled into a single evaluation item, while bitterness and its aftertaste were set up as separate items. Here egumi is tied together with astringency rather than bitterness, and how it splits differs by food.

Exceptions and reservations

The definition of egumi itself shifts depending on the food in question. In the sensory evaluation terminology system for cooked rice, egumi is defined as "a husky sensation as if aku were clinging to the tongue and throat," and is treated as a basic taste separate from bitterness.

In soy sauce evaluation terms, egumi is bundled into one item with astringency and is separated from bitterness. In spinach research, the "oxalate taste" closest to egumi and bitterness fall into separate chemical fractions. The same Japanese word egumi ends up placed next to bitterness or next to astringency depending on the food in question — when talking about the state of egu-bitter, it is necessary to make clear which food's egumi is meant.

The spinach research remains a sensory evaluation by a small number of people, a quality check by assessors including the authors, and is not a common scale usable for egumi in general. The soy sauce research, too, has only been checked as far as the abstract, and within the combined item, the respective contributions of astringency and egumi are not separated. Sources showing a reversal due to individual differences or concentration have not yet accumulated.

Examples from around the world

The encyclopedia entries below are in Japanese.

• Spinach — the subject of the report that oxalate taste and bitterness separate into different fractions
• Takenoko (bamboo shoot; moso bamboo) — a food recorded as varying in bitterness and aku strength depending on the soil of its growing region
• Takenoko misoni (Toyama-style simmered bamboo shoot) — a local dish of Toyama Prefecture; parboiled bamboo shoot simmered through with miso
• Namul — a Korean group of side dishes made by boiling or sautéing edible wild greens and other plants and dressing them
• egumi (Japanese food descriptor) — the Japanese sensory term, treated with a definition attached for each food and usage

Try it at home

Status: candidate (to be published once a tasting-comparison record is attached)

Comparing spinach by boiling time

There is 1 variable: boiling time. Divide spinach from the same bunch into 3 equal portions, dip each into boiling water under 3 conditions — short, medium, and long — then cool them the same way in cold water. If the amount that dissolves into the boiling liquid changes with time, the same taster can compare them one after another to check whether how egumi and bitterness remain differs by condition.

Comparing soy sauce raw and pasteurized

The variable is whether the soy sauce has been pasteurized (hi-ire) or not. Prepare a raw (nama) and a pasteurized soy sauce from the same brand series, and pour the same amount over the same tofu or sashimi to compare by tasting. This condition checks whether you can put into words the combined feeling of astringency and egumi, separately from the feeling of bitterness and its aftertaste; it does not address any health meaning of the amount or degree of heating.

What is not known

• In the spinach experiment, the intensities of oxalate taste and bitterness were recorded only as plus/minus symbols, not as numbers, so how strong they were has not been measured.
• Whether the explanation that oxalic acid is felt as crystals forming in the mouth is the same as the conditions under which egumi is actually felt has not been directly confirmed.
• For takenoko and other foods often named as leading examples of egumi, no source has been found, within the evidence gathered for this page, that measured egumi and bitterness separately.

Between the dictionaries

Whether the identically formed compound word "egu-bitter" appears in dictionaries has not been confirmed. What dictionaries do carry is the entry for "egui," one of whose senses references bitterness.

The same entry also records, alongside it, a figurative sense unrelated to taste.

"Egoi," a variant with the same meaning as "egui," is also recorded within the same dictionary entry, and its example sentence includes a reference to bitterness alongside sourness.

The difference from horonigai is the difference between muting bitterness and standing alongside it.horonigai (gently bitter) is the result of another taste blunting bitterness without leaving its own outline behind, and it is positioned on the inside of the bitterness-intensity axis. Egu-bitter, conversely, refers to a state in which egumi remains standing alongside bitterness as a separate sensation. Muting it, or standing beside it — these are not the same story of "lightened bitterness."

Frequently asked

Is spinach's egumi the same thing as its bitterness?

Within the research we were able to check, they are different things. The two separate into water-extracted and ethanol-extracted components, and the bitter-side substance has been concluded not to be oxalic acid.

Does removing the aku from wild greens also remove the bitterness?

This cannot be answered from the sources on this page alone. The local-dish record for takenoko describes a parboil using rice bran and dried red chili, but no source yet gives numerical figures for how much bitterness or aku is reduced.

Is soy sauce's "egumi" a kind of bitterness?

In the evaluation-term design we were able to check, egumi taste is bundled with astringency, not bitterness, into one item. To speak of the state of egu-bitter, the grounding needs to come from the spinach-side reports rather than from soy sauce.

Related: Bitter crossings /Does any seasoning remove bitterness? — Sugar and salt /How Bitterness, Astringency, and Egumi Differ /Wild-Greens Dish Names Do Not Mean One Plant /Bitterness, Astringency, and Egumi