Young North Sea herring lightly salt-cured through enzymatic maturation, yielding a silky, mildly briny fillet served chilled with raw chopped onion — a fleeting June-July delicacy celebrated with annual festivals on the Belgian and Dutch coasts.
The foundational technique — gibbing herring while retaining the pancreas to allow enzymatic ripening in salt — is attributed to Willem Beukelszoon of Biervliet (Zeeland) around 1380, transforming North Sea herring into a storable commodity that fuelled Low Countries maritime trade. The catch window is strictly limited to mid-May through late June, when pre-spawning herring reaches peak fat content of 16–26%; after spawning the fish exhausts its fat reserves and quality falls sharply. Belgium's coastal city of Ostend holds an annual Maatjes Festival at the Vissersplein in June, where the season's first barrel arrives at the Visserskaai in the early afternoon. In the Netherlands, the ceremonial Vlaggetjesdag (Flag Day) at Scheveningen and Vlaardingen auctions the inaugural catch for charity. The word maatjes derives from the Dutch maagdenharing (virgin herring), denoting females not yet carrying developed roe.
The flesh dissolves on the tongue — silky, yielding, lightly briny with a sweet richness from omega-3 fat and free amino acids released during enzymatic ripening; the pungent raw onion slices through the fat and resets the palate with each bite.
The retained pancreas secretes trypsin and chymotrypsin into the salted flesh; in 10–15% brine these proteolytic enzymes remain active and progressively cleave myosin and actin proteins into short peptides and free amino acids over 4–7 days. This proteolysis softens muscle fibres to a characteristic silky texture while generating glutamate-rich umami compounds. Simultaneously, osmotic pressure from salt draws water out of cells, creating an inhospitable environment for spoilage bacteria while leaving the beneficial pancreatic enzymes active. Before salting, a mandatory freeze at −45 °C for a minimum of 24 hours destroys anisakis parasites; the thawed fish then enters brine for controlled maturation at 0–4 °C.
Variations
Hollandse nieuwe (Dutch new herring) is the officially recognised variant with strict fat-content and catch-season regulations. Belgian new maatjes follow identical principles, with the first barrel of the season ceremonially received at Ostend's June festival. Traditionally consumed whole — held by the tail and lowered into the open mouth — maatjes are also served sectioned with chopped onion and pickles, or tucked into a soft bread roll. Bokking (cold-smoked heavily salted herring) is a related but sharper winter tradition from the same Low Countries heritage.
On the Palate
Where Maatjes / Hollandse nieuwe sits in the Belgian flavor cloud
Ingredients
Serves 4How it's made
7 steps · 30 min
- 110 min
Select young pre-spawning North Sea herring caught between mid-May and late June, at 16–26% fat content.
- 215 min
Gibb the fish: remove gills and intestines with a small knife, deliberately leaving the pancreas intact.
Watch outWhen you gut the fish, deliberately leave the pancreas in — its enzymes are what ripen the flesh silky over the cure; cut it out and you just get salted raw herring.
- 31440 min
Freeze the gibbed fish at −45 °C for a minimum of 24 hours to eliminate anisakis parasites.
- 415 min
Thaw the fish and layer alternately with coarse sea salt in wooden barrels; submerge in a 10–15% brine solution.
- 57200 min
Mature in cold storage at 0–4 °C for 4–7 days, allowing pancreatic proteolytic enzymes to ripen the flesh to silky tenderness.
Watch outRipen cold at 0 to 4 for four to seven days — that's the window where the enzymes soften the flesh and build umami; warmer or longer and it turns mushy and off.
- 610 min
Remove the backbone from the gill end to just above the tail, leaving the tail fin attached.
- 75 min
Serve chilled at maximum 7 °C with finely chopped raw white onion alongside, and optional soft white bread rolls.
