I just found weird-food.com. Here's a description of someone's experience with surstromming:
The most disgusting thing I've ever attempted to eat in my life must go to a Swedish dish called Surstromming, translated into English as 'fermented herring.' Now, surstromming is something that I often heard mentioned by friends, "Hey, Bob, have you eaten surstromming yet, hah hah hah?" I knew that it was fermented fish and that eating it would be a challenge but, having eaten all sorts of weird seafood when I lived in Spain, I was determined to give it a go.
One day, just around lunchtime, I was shopping in my local supermarket when I came across a tin of the stuff. "Well, now seems as good a time as any," I thought, and popped it into my shopping basket. When I got back home, I put it in the middle of the kitchen table and took a tin opener out of the drawer. Now, what no one had told me was that fermenting builds up quite a lot of pressure inside the can and that you should always cover a surstromming can with a cloth before you open it. The other thing I didn't know is that surstromming is usually eaten outdoors.
I leaned over the tin and just at the moment I pierced it, there was a hissing sound and then a fountain of juice shot into the air and spattered the left lens of my glasses - thank goodness I was wearing glasses; I hate to think what it could have done to my eye. Then, the air in the room was filled with a stench that was reminiscent of a public toilet that hadn't been cleaned for 20 years. I picked up a piece of the fish on my fork, held my breath, screwed up my eyes and placed it into my mouth.
Can you imagine how a solidified lump of surgical spirit would taste? Well, that's the feeling I had as it burned into my tongue. I rushed over to the kitchen sink, spat it out, coughed a lot, and drank several glasses of water. Then I went back to the table, tied up the can in 3 plastic bags and dumped it in the garbage. Some of the juice had spilled onto the plastic tablecloth, so I wiped it up with a dishcloth, opened the window to get rid of the stench and then left the room.
When I went back into the kitchen 10 minutes later, I beheld the most nauseating thing I've ever seen in my whole life. The room was full of flies - about forty of them and they were just going absolutely crazy, charging all around the room at supersonic speed, bouncing off one wall, then bouncing off the opposite one. I put my handkerchief over my mouth (the fact that I didn't throw up was close to miraculous), ran over to the window and closed it. I then ran for some fly spray and just sprayed continuously for over a minute. Then I left the room and waited for about 10 minutes. Finally, I looked back in - all the flies were lying on the floor. I got the vacuum cleaner out of the room and swiftly disposed of the remains.
Sweden has some nice dishes. I loved pytt i panna, Janssons frestelse, and pickled (as opposed to 'fermented' herring) washed down with Swedish schnapps is a wonderful treat. But as for surstromming... well, enough said.
