雲丹 · ウニ · uni

Uni

Uni is sea urchin — the sweet, briny, custard-rich gonad served raw as gunkanmaki. Quality ranges wildly, and that gap is the whole game.

Also known as

sea urchin roe, bafun uni, murasaki uni

Species

Strongylocentrotidae (Sea urchin (bafun & murasaki))

Category

Roe & uni (gunkanmaki)

Texture

creamy, custard-like — sweet, briny, oceanic, umami

Peak season

Jun, Jul, Aug, Dec, Jan

Sustainability

varies — Depends on species and fishery; some urchin harvests help control kelp-destroying populations.

Mercury

Not in the FDA consumer table

Pregnancy

Avoid (raw)

Price tier

$$$$

What uni is

Uni is sea urchin — specifically the animal’s gonads (often poetically called “tongues”), served raw, usually as gunkanmaki (“battleship” rolls) wrapped in nori. At its best it’s sweet, briny and custard-rich; at its worst, bitter and metallic. The gap between those two is the whole game.

Bafun vs murasaki

Two types dominate Japanese counters: bafun uni, smaller and deep orange with an intense, sweet richness, and murasaki uni, paler yellow and cleaner-tasting. Hokkaido is the prestige source.

Season and quality

Uni peaks in summer and again in winter depending on species and region. One nerd warning: lower-grade uni is often treated with alum to hold its shape, which leaves a bitter, ammonia-like off-note. Top counters serve untreated (muban) uni, which tastes markedly sweeter and cleaner.

Safety

Uni is very low in mercury, but it’s served raw — standard pregnancy guidance is to avoid raw seafood. Freshness is everything: good uni smells of clean ocean, never of ammonia.