You can find tender and tasty Dutch soused herring in every fish stall or fish shop in the Netherlands. This Dutch speciality is not cooked and it’s not exactly raw, and if you want to have it at its very best you should eat it as soon as the fishmonger hands it over.

When Dutch soused herring is prepared in the traditional way and sold in the year the fish are caught, it can be called Hollandse Nieuwe (Holland’s New). These days soused herring is frozen after processing and is available all year round, but it used to be stored in salt, and it would get saltier and less ‘fresh’ the longer it was kept. The start of the new herring fishing season each year was seen as a symbol of better times to come, and to mark this the boats of the fishing fleet would be decorated with flags the day before they left the harbour. Nowadays, Flag Day (Vlaggetjesdag) celebrates the arrival of the new season’s soused herring, in Scheveningen. This year it will be on 18th June and it will herald the appearance of Hollandse Nieuwe stalls in many supermarkets and workplace canteens.

Herring lose weight during the winter months and then start to fatten up as the food supply increases. To qualify as Hollandse Nieuwe, the herring have to have a fat content of 16% or higher. The fish should be at least three years old, but should not have started to produce any sperm or eggs yet that year. This is why they are also called ‘maatjesharing’, a corrupted form of ‘maagdenharing’ or virgin herring. Generally they are caught between mid-May and July.

After the fish have been caught, the gills are removed and the fish are gutted, but the pancreas is left in, so its enzymes can contribute to the ripening process. The fish are kept in dry salt or brine for a period of up to four days, depending on the size, weight and fat content of the fish. The herrings are then frozen for at least 24 hours to ensure that any parasites are killed, and they can be kept frozen for a long time without any loss of quality. After thawing, they are filleted and skinned for eating, and should taste ‘creamy, lightly salty and tender’, but the ripening process will restart, which is why it’s best to eat the fish as soon as possible

The preservation method for Hollandse Nieuwe herring has been used since at least the 14th century. In 1384 access to local curing and packing services was withdrawn from Dutch fishers in the principal centre of herring fishing, the region of Schonen in Denmark. They were not welcome in England either, so they started to process the fish on board ship and worked to perfect this manner of preserving herring. Since the fish could then be kept for longer, fishers could stay longer at sea and use bigger fishing boats. Welfare also increased, and feeding Dutch sailors with herring may have played a role in helping the Netherlands to gain its dominant position on the world stage in the seventeenth century.

Hollandse Nieuwe is important to the Dutch, and in October 2015 it gained the EU’s ‘Traditional Speciality Guaranteed’ status. The herring doesn’t have to be prepared in the Netherlands, though. At the end of the 1970s, fish stocks were down and fishing was not allowed in the North Sea, so Dutch fish processing firms moved to Denmark, and herrings were processed in the Dutch way in Jutland. Although the North Sea was opened up to herring fishing again in 1983 the Dutch continued to buy and process Danish herring. These days Norwegian, and to a lesser extent Scottish, herring are also prepared for the Dutch market and a lot of the processing is automated.

There are local traditions about the best way to eat Dutch soused herring. Inland regions favoured saltier herring than coastal areas as it took longer to reach them, and they needed to be kept for longer. In Brabant and in Rotterdam they traditionally eat smaller herring, sometimes dipped in diced raw onion, and then held up by the tail and eaten whole! Originally the onion was added to counteract some of the saltiness, but the tradition has remained even though the fish are less salty these days (1.1 %). In Amsterdam, herrings tend to be larger, cut into sections and, again, often with chopped onions on top or a gherkin, though they are also available served in a soft white bread roll. In any case, they’re a great source of omega 3- fatty acids, protein and vitamin D, and they taste good.