Category: Interesting facts

Surströmmingsfest: Sweden’s Fermented Herring Tradition Explained

Few Swedish food traditions divide opinion quite like surströmming. Being invited to a surströmmingsfest can be seen as a warm and memorable gesture — but actually eating surströmming is a different matter. For some, it is a beloved northern delicacy. For others, it is one of the most challenging food experiences Sweden has to offer.

Surströmming is often described as one of Sweden’s most unusual traditional foods. In simple terms, it is fermented Baltic herring. The fish is allowed to ferment before it is packed into tins, giving it its famously strong smell and distinctive flavour.

A surströmmingsfest is therefore not just a meal. It is a cultural event, a conversation starter and, for many language learners, a fascinating window into Swedish food history, regional identity and vocabulary.

What is surströmming?

The Swedish word surströmming consists of two parts:

sur = sour
strömming = Baltic herring

So the word can be understood as soured or fermented herring.

Surströmming is made from Baltic herring that has gone through a fermentation process. Fermentation, or jäsning in Swedish, has been used for thousands of years as a way to preserve food. Long before modern refrigerators and freezers, people needed methods to make food last longer. Salting, drying, smoking and fermenting were all important techniques.

Surströmming became especially valuable because of its long shelf life. Historically, this made it useful in situations where food needed to be stored and transported, including military contexts.

Today, surströmming is closely associated with northern Sweden, especially Norrland, with production centred around the High Coast area, known in Swedish as Höga kusten.

Why is surströmming so controversial?

Surströmming is a true vattendelare — a Swedish word that literally means “watershed”, but is often used to describe something that strongly divides opinion.

Some people appreciate surströmming as a traditional delicacy with deep cultural roots. Others find the smell extremely difficult to handle. Even many Swedes have never tried it, and among those who have, reactions can be very different.

This is one of the reasons why a surströmmingsfest can be such a memorable social event. It is not only about taste. It is about courage, humour, curiosity and tradition. For foreign visitors and Swedish learners, it is often one of those cultural experiences people remember for a long time.

How is surströmming made?

Surströmming is essentially fermented strömming, or Baltic herring. The fish is usually caught during the spring spawning season. After being caught, it is placed in saltlake, meaning brine — water saturated with salt — in large open wooden containers.

After a few days, the herring is transferred into a new brine, this time with a lower amount of salt. This is important because the fish must be preserved, but the fermentation process also needs to continue.

The fermentation itself requires warmth. Traditionally, the barrels may be placed in sunlight, allowing the process to develop under the right conditions. When the herring begins to ferment, the barrels are kept at around 15–18°C for up to eight weeks.

After this, the fish is packed into metal tins and distributed across Sweden — and sometimes even to other parts of the world.

What do people eat with surströmming?

Surströmming is rarely eaten on its own. It is usually served with simple but important accompaniments that balance the strong flavour of the fish.

A traditional surströmmingsfest often includes:

The most common way to eat surströmming is with tunnbröd, boiled potatoes and finely chopped onion. Many people make a kind of open or rolled flatbread sandwich, where the strong fish is combined with milder ingredients.

The meal is often washed down with beer, and sometimes with snaps, a traditional Scandinavian spirit often served at festive meals.

Surströmmingsfest: more than just fermented fish

A surströmmingsfest is a gathering where people come together to eat surströmming in a social setting. The atmosphere is often informal, humorous and curious. Since the smell of surströmming is very strong, the meal is often enjoyed outdoors.

For many people, the experience is just as important as the food itself. Opening the tin, reacting to the smell, preparing the tunnbröd, tasting the first bite and sharing the moment with others are all part of the tradition.

This is why being invited to a surströmmingsfest can feel special. It is a way of being included in a very distinctive part of Swedish food culture — even if not everyone becomes a fan of the dish.

Useful Swedish words connected to surströmming

Food traditions are excellent for language learners because they connect vocabulary with real cultural situations. Here are some useful Swedish words from the world of surströmming:

A few simple example sentences:

Surströmming är jäst fisk.
Surströmming is fermented fish.

Vi blev bjudna på surströmmingsfest.
We were invited to a surströmming party.

Man äter ofta surströmming med tunnbröd och potatis.
Surströmming is often eaten with flatbread and potatoes.

Surströmming är en riktig vattendelare.
Surströmming really divides opinion.

Language insight: the word “vattendelare”

One particularly useful word in this topic is vattendelare. Literally, it means “watershed” or “water divider”. In everyday Swedish, however, it can also be used figuratively for something that separates people into different camps.

Surströmming is a perfect example of a vattendelare. Some people love it, some strongly dislike it, and many are simply curious to try it once.

For Swedish learners, this word is useful far beyond food. It can also be used when talking about films, politics, fashion, cultural debates or any topic that strongly divides opinion.

What does surströmming teach us about Swedish culture?

Surströmming may seem unusual at first, but it tells us a lot about Swedish history and regional identity. It reminds us of older methods of preserving food, of the importance of fish in Nordic cuisine, and of the strong connection between food and place.

The tradition is especially connected to northern Sweden, where nature, fishing and preservation methods have long shaped everyday life. Today, surströmming is not eaten because people have no other way to preserve fish. It is eaten because it carries tradition, memory and identity.

It also shows something important about Swedish humour. A surströmmingsfest often includes laughter, curiosity and shared reactions. The strong smell is not hidden — it is part of the experience.

Learning Swedish through food traditions

Learning Swedish becomes more meaningful when words are connected to culture. A word like surströmmingsfest is difficult to understand fully if we translate it only as “fermented herring party”. Behind the word there is a whole cultural scene: northern Sweden, fermentation, flatbread, potatoes, onion, beer, snaps and strong opinions.

For language learners, topics like this make vocabulary easier to remember. Instead of learning isolated words, students learn them through real-life situations: invitations, food, celebrations, regional traditions and conversations around the table.

If you would like to learn Swedish step by step, explore our Swedish courses.

Kristi Himmelsfärdsdag in Sweden: A Red Day, a Long Weekend and a Useful Swedish Word to Know

What is Kristi Himmelsfärdsdag?

If you are learning Swedish, sooner or later you will come across the long word Kristi himmelsfärdsdag. In English, it means Ascension Day.

In Sweden, Kristi himmelsfärdsdag is a röd dag, which means a public holiday or literally a “red day”. Public holidays are often called röda dagar in Swedish because they are traditionally marked in red in calendars.

For many people in Sweden, this day is associated with spring, extra time off and, quite often, the possibility of a longer weekend.

When is Kristi Himmelsfärdsdag?

Kristi himmelsfärdsdag is a movable holiday, which means that it does not fall on the same calendar date every year.

It is celebrated 40 days after Easter Sunday and therefore always falls on a Thursday.

In 2026, Kristi himmelsfärdsdag falls on Thursday, 14 May.

Why is it celebrated?

In the Christian tradition, Ascension Day commemorates the day when Jesus is believed to have ascended into heaven after his resurrection. According to Christian belief, this took place after he had appeared to his followers during the 40 days following Easter.

So, while Easter is connected to the resurrection of Jesus, Kristi himmelsfärdsdag specifically refers to the Ascension.

“Kristi flygare” – a more informal name

You may also hear the humorous or informal expression Kristi flygare in Swedish. This is a playful way of referring to Kristi himmelsfärdsdag, connected to the idea of “flying” or “going up”.

For Swedish learners, this is a good example of how Swedes sometimes shorten or play with long words in everyday language.

Useful Swedish vocabulary

Here are a few words and expressions worth learning:

The word klämdag is especially useful. Since Kristi himmelsfärdsdag always falls on a Thursday, many people take the Friday off as well. This creates a four-day weekend. In Swedish, that Friday is often called a klämdag.

Why culture helps you learn Swedish

Learning a language is not only about grammar and vocabulary. It is also about understanding how people live, work, celebrate and communicate.

Swedish holidays such as Kristi himmelsfärdsdag help learners understand everyday references in conversations, workplace calendars, school schedules and public announcements. If you live in Sweden, work with Swedish colleagues or plan to use Swedish professionally, knowing these cultural terms can make communication much easier.

At InterLanguage, our Swedish courses are built around structured language development, personal attention and practical communication. Learners can study Swedish from beginner to advanced levels in a CEFR-based module system, with individual or small-group options.

A short language tip

The word himmelsfärdsdag may look difficult at first, but you can break it down:

himmel = heaven / sky
färd = journey / travel
dag = day

So, Kristi himmelsfärdsdag can be understood as “Christ’s journey-to-heaven day”.

Breaking long Swedish words into smaller parts is one of the most useful strategies for adult learners.

You can check Swedish word meanings, spelling and pronunciation on svenska.se, the official dictionary portal of the Swedish Academy.  

Final thought

Kristi himmelsfärdsdag is more than just a date in the Swedish calendar. It is a useful cultural and linguistic topic for anyone learning Swedish. It teaches you about Swedish public holidays, Christian traditions, everyday expressions and even the Swedish habit of creating long compound words.

And next time you see röd dag in a Swedish calendar, you will know exactly what it means.

In Sweden, Epiphany (Trettondedag jul) is observed on January 6 and is an official public holiday, commonly referred to as a “red day”. The name trettondagen refers to the fact that January 6 falls on the thirteenth day of the Christmas period. In this calculation, Christmas Day on December 25 is counted as the first day of Christmas, meaning that Epiphany comes thirteen days after Christmas Eve. In most Christian countries, Epiphany marks the end of the Christmas season.

 In the Nordic countries, however, the Christmas period lasts longer. In Sweden, Christmas is traditionally concluded on tjugondedag jul, also known as St. Knut’s Day, which falls on January 13, twenty days after Christmas Eve.

From a historical perspective, Epiphany holds particular significance. In the early days of Christianity, January 6 was celebrated as the birthday of Jesus. In the 4th century, this celebration was moved to December 24 or 25. As a result, Epiphany is considered the oldest Christian feast. On January 6, the tradition commemorates the arrival of the eastern Magi – the Three Wise Men – in Bethlehem, where they are said to have brought gifts to Jesus: gold, frankincense, and myrrh.

Epiphany is a clear example of how language, history, and tradition are closely interwoven in Swedish culture, and how an ancient celebration continues to be observed today.

Our native Swedish teacher told us about one of their sweet treats:

“Semla is something we eat in Sweden before Lent. It is a sweet bun filled with an almond paste with a lot of whipped cream. This rich, extravagant treat is meant to be the feast before fasting (though most of us who eat these don´t continue with the fasting part….). So, the Swedish celebrate Lent with a Hungarian-looking pastry (képviselő fánk) with a German name – a nice symbol for how intertwined we are with other countries.”