Must was created by Harry Roberts in the early 1900s as a non-alcoholic alternative to beer. And the syrup is still made exclusively by Roberts AB in Örebro. The original recipe is said to be locked up in a safe and only one person knows the full recipe.
Must is made of carbonated water, sugar, hops extract, malt extract, spices, colouring (E150), citric acid, and preservatives. The hops and malt extracts give the must a somewhat beerlike taste, but must is not fermented and contains no alcohol. Must can be aged provided it is stored in a glass bottle. Some people buy must in December only to store it a year before drinking it.
Julmust might be the source of some annoyance at Coca-Cola in Sweden, since Sweden is the only country where the consumption of Coca-Cola drops during Christmas. Many Swedes drink julmust instead. This was quoted as one of the main reasons Coca-Cola broke away from their contract with Pripps and started Coca-Cola Drycker Sverige AB instead. Ironically enough, Coca-Cola later felt it was necessary to make their own julmust.