The best lingonberry jam is prepared with berries, sugar and sometimes a small amount of water. Cheaper varieties can be diluted with apples. Sweetened lingonberries (rårörda lingon) or (rørte tyttebær) are made fresh by just mixing berries and sugar, without boiling. Because of the benzoic acid, which is found in high amounts in lingonberries, the berries keep well without any preservatives.[4][5]