Tjukkmjølk (“thick milk”) is a traditional and distinctive product of the city of Røros, with more than a century of history. The origins of this particular product appear to date back to 1850, when Røros (a UNESCO World Heritage Site) began to establish itself as a center for mining activities. Forced to complete fast-paced and tiring work, the miners brought large quantities of milk from home and left it to acidify so that they would always have some food to support their efforts.
The name of the product refers to its dense consistency, which is a result of a particular ingredient that is added to the milk: the leaves of Pinguicula vulgaris, or butterwort, a carnivorous plant with thick and fleshy leaves. The production of tjukkmjølk begins with the harvest of the butterwort, after which the leaves are rinsed and placed in a wooden bowl that is reused each time the product is made. Fresh milk is then poured into and the bowl is left to rest in a warm, sheltered place. When the milk begins to become dense and to resemble yogurt, the tjukkmjølk is ready.
The product has a similar consistency to pudding with a very acidic flavor. Tjukkmjølk is eaten for breakfast in a porridge made of oats, or as a refreshing snack during the summer season. It also tastes good paired with meat or sausage.
Tjukkmjølk is usually prepared for domestic consumption, even though butterwort leaves are becoming increasingly scarce. This product is very important in the area of Røros, where a few small companies exist which make tjukkmjølk and sell it in local markets.