Hongeo Explained: Why Fermented Skate Smells Like Ammonia

Hongeo can announce its arrival before the plate reaches the table. The fermented skate's ammonia-rich aroma is notorious even within South Korea, frequently compared to ammonia-based cleaning products. Strongly fermented versions can produce a sharp, ammonia-like sensation that rises into the nose. Despite this formidable reputation, hongeo is an alkaline-fermented skate product rather than simply spoiled fish. In modern production, fermentation conditions can be deliberately managed, while the historical tradition is associated with spontaneous fermentation. Its famous ammonia aroma comes directly from the skate's unique physiology.

Why Skate Produces Ammonia

The creation of hongeo relies on the biology of cartilaginous fish. Scientific studies of hongeo have used several skate identifications and historical taxonomic names, including Raja pulchra and Raja kenojei. Because skate taxonomy and commercial sourcing vary across the literature, hongeo should not be treated as referring exclusively to one species. Skates maintain their osmotic balance in seawater by retaining unusually high concentrations of urea in their tissues. When the skate dies, microbial and enzymatic activity breaks down nitrogen-rich compounds in the flesh. Urea contributes to ammonia formation, while TMAO can be converted into trimethylamine and related volatile nitrogen compounds.

Why Hongeo Ferments Instead of Simply Rotting

In ordinary seafood, comparable microbial activity would usually be associated with rapid spoilage. However, for the skate, the accumulation of ammonia creates a highly alkaline environment. This increasingly alkaline condition inhibits many spoilage and harmful microorganisms, helping the fermented skate remain stable under controlled processing conditions. Fermentation time varies considerably with temperature and production method. While the high pH provides a natural preservation effect, it does not make the product completely sterile; food hygiene and proper handling remain crucial.

How Did Hongeo Become a Jeolla Tradition?

A widely repeated origin story links fermented skate to the long journey from Heuksando, an island off the southwestern coast, toward Mokpo and the inland river port of Yeongsanpo in Naju. Before modern refrigeration, transporting fresh fish was a slow process. According to the accounts, the skate underwent spontaneous fermentation and reportedly remained edible while other fish spoiled. The story reflects a real geography of skate distribution: Heuksando became famous for prized catches, Yeongsanpo developed a historical association with fermented skate, and Mokpo later emerged as the major auction and distribution center.

Hongeosamhap: A Combination of Three

Today, hongeo is sliced thinly and served uncooked after fermentation. Its texture is firm, elastic, and chewy, with a noticeable crunch from the cartilage. Because the intensity can be overwhelming, it is often eaten as part of a trio known as hongeosamhap, meaning roughly "a combination of three." The fermented skate is paired with boiled pork belly (bossam) and aged kimchi. The richness and softer texture of the pork temper the sharp flavor of the skate, while the acidity of the aged kimchi helps soften the perceived ammonia sharpness. This three-part combination itself appears to be a later culinary development rather than the original way fermented skate was eaten.

How Strong Does Hongeo Really Smell?

Viral descriptions often present hongeo as uniformly extreme, but fermentation intensity varies considerably between producers and restaurants. Not every plate is equally pungent. Some specialty restaurants offer less-fermented preparations that provide a gentler introduction for first-time diners.

Where to Try Hongeo in Mokpo

Today, Mokpo hosts Korea's largest skate auction market and is one of the country's principal centers for hongeo culture. Restaurants such as Namdo Arirang are often recommended by the Korea Tourism Organization for offering both intensely aged cuts and more beginner-friendly, lightly fermented versions. (Note: availability and prices can change; it is always recommended to check locally before visiting).

Hongeo in Jeolla Today

Within South Korea, hongeo remains a culturally significant regional specialty. In parts of Jeolla, hongeo has long been associated with communal dining and regional identity. The continued consumption of hongeo preserves a unique culinary adaptation that reflects both the region's geography and the distinct biology of the skate itself.