Swedish Fermented Fish РSurstr̦mming

“Surströmming” translates literally as “soured herring”, which is a woefully inadequate description of the monster that is this particular Swedish delicacy.  The herring is fermented in barrels for a month or two and then tinned, but continues fermenting in the tin with the result that the tins often end up bulging worryingly and some airlines have banned them on the basis that they could explode dangerously while in flight.

With all this fermentation comes carbon dioxide (which causes the bulging) and also by-products.  This is a bacterial fermentation rather than the yeast-based fermentation that is used to produce alcohol in wine and beer.  Modern wine-making techniques insist on scrupulous cleanliness in order to prevent unwanted bacterial fermentation precisely because the by-products of these fermentations will taint the wine with unpleasant tastes and aromas.  Surströmming-making techniques obviously encourage this fermentation, which the result that opening a tin of the stuff releases the most ungodly smell known to man.  So much so that when renting an apartment in Sweden, the rental agreement will forbid you to eat it in your apartment.

Why am I telling you all of this?  Well, last night we went to a barbecue with several friends of ours where we cooked some sausages, chops, burgers, etc, and played Kubb, which is a strange Swedish game involving throwing bits of wood at other bits of wood.  To keep in with the Swedish theme, Lars (who is Swedish after all) did something that he has been threatening to do for a while – he very kindly and no doubt at great risk to himself, brought along a few tins of surströmming.

There is a technique of opening the tin in a bucket of water to hide some of the smell, but we didn’t have a lot of luck with this.  In fact, for a while we didn’t have much luck opening the tin at all; Lars tried various openers but none of them were quite up to the job of piercing the armour-plated tins and it took his better half’s touch to get it going finally.  When we eventually did get the tin open, the crowd of curious onlookers that had gathered close by instantly dispersed far and wide to escape the intense reek that emanated from within.  It smelled Wrong.  Like super-concentrated rotten eggs that had gone even more rotten than could be thought possible.

Certain foodstuffs smell bad but are still definitely edible and are indeed particularly delicious.  A good example would be Epoisses and similar types of cheese that smell like sweaty socks but taste powerfully rich and creamy.  Or an aged, particularly “farmyardy” red Burgundy which tastes of a perfectly elegant marriage of fruit and earthiness with a touch of spice.  With this in mind, I was determined to fight past the seemingly impenetrable wall of pestilence and try it.  There was a certain amount of instinct-suppression going on and I had to push the “this smells like it’s going to kill me” thoughts to the back of my mind.

After opening, the herring fillets are removed from the tin, washed in sparkling water and served with “tunnbröd” flat bread and several other accompaniments, namely boiled potatoes, chopped red onion, sliced tomato, dill and a Swedish type of cottage cheese.  Being a particularly premium brand of  surströmming, this one included a lot of the roe along with the fillets.  We rolled all of this up in the tunnbröd to make a sort of wrap and then ate it that way.  Watching Lars make his, he arranged all of the accompaniments on his tunnbröd, then topped it with two large fillets of surströmming and two large pieces of roe before rolling it all up.  Trying to do it correctly of course, I copied his example closely.

How to describe the flavour?  Well, the closest way I can think of emulating the taste would be to drink Thai fish sauce straight from the bottle.  And in a similar way, if you have a little of it mixed in with other things, it tastes rather good, but if you have too much then its overwhelming pungency just takes over.  The potatoes and cottage cheese are essential for diluting its intensity, but sometimes you do get more fish in a mouthful than you bargain for, especially as the skin is still on the fillets and makes biting through it difficult.  I survived though, and even went back for a second helping.  Traditional carraway snaps is also important here.

Curious about why people would want to make something like this, I did some searching on the interwebs this morning.  Obviously it is a way of preserving the fish for future consumption from the days before refrigeration, but then so are curing, smoking, salting, etc, and they result in rather less offensively pungent products.  What I found out was that the fermentation proess does use a little salt, but it uses a lot less of it than salting or brining would and in days gone by, salt was scarce and/or expensive.  So that makes a bit of sense.

As for the smell, and how something that smells so obviously rotten can somehow still be edible, Wikipedia was quite helpful here.  The four main smell categories are “pungent”, “rotten egg”, “rancid butter” and “vinegary” (I can attest to these all being present in copious amounts) and these are given off as by-products of fermentation by a particular type of bacteria.  However, it is a different type of bacteria that would actually break down the fish proteins and rot it and this type of bacteria is killed off by the salt that is added.  Which makes sense too, but the brain still has a way of associating these smells with something being rotten.

So, a rather smelly food adventure, but one that was certainly worthwhile.  It is certainly an acquired taste, and Lars ensures me that over the few times that he’s had it, he has definitely moved out of the “distinctly wary” camp into the “actually it’s not too bad, I think I’ll have some more” camp.  I’m not sure when I’ll have it again, but hopefully I’ve started on that path.