what is surstromming made of
Fermented herring. SurstrÃ¶mming. SurstrÃ¶mming (fermented Baltic herring or, literally, soured Baltic herring), is one of Sweden's most infamous products and is especially popular in northern Sweden. SurstrÃ¶mming can only be made from strÃ¶mming (Baltic herring), which are smaller than sill (Atlantic herring).