Rollmops are usually bought ready-to-eat, in jars or tubs. The marinade additionally contains water, white vinegar, and salt; it may also contain sugar or other sweetening agents, onion rings, peppercorns and mustard seeds. Rollmops can be eaten cold, without unrolling, or on bread. After the jar has been opened, they will usually keep for two to three weeks if kept cool or refrigerated.
In German, the word Rollmops is singular with the umlaut-plural form Rollmöpse. The name "rollmops" is German in origin, originating from the words rollen (to roll) and Mops (German name of pug dogs / "blockhead").
Pickled herrings have been a staple in Northern Europe since Medieval times, being a way to store and transport fish, especially necessary in meatless periods like Lent. The herrings would be prepared, then packed in barrels for storage or transportation.
Rollmops grew popular throughout Germany during the Biedermeier period of the early 19th century and were known as a particular specialty of Berlin, like the similar pickled herring dish Bismarckhering. A crucial factor in their popularity was the development of the long-range railway network, which allowed the transport of herring from the North and Baltic seas to the interior. The fish was pickled to preserve it and transported in wooden barrels. In pubs in Old Berlin, it was common to have high-rising glass display cases known as Hungerturm (meaning "hunger tower") on the bar to present ready-to-eat dishes like lard bread, salt eggs, meatballs, mettwurst, and of course rollmops. At the present time, rollmops are commonly served as part of the German Katerfrühstück (hangover breakfast) which is believed to restore some electrolytes.
Rollmops are eaten in Europe and South America.
See also 
|Wikimedia Commons has media related to: Rollmops|
- Mrs Beeton's Everyday Cookery. Ward Lock Ltd. 1963 edition. ISBN 0-7063-1403-4.
- South African Concise Oxford Dictionary. Oxford University Press. 2002. ISBN 0-19-571804-6.
- American Heritage Dictionary of the English Language Fourth Edition. http://www.bartleby.com/61/1/R0290100.html: Boston: Houghton Mifflin Company. 2000. ISBN 0-395-82517-2.