During extraction of peat close to the farm Austrått at Ørland, Norway in 1927, they came upon a round box or container made of birch bark. The birch bark box was found at the bottom of a peat bog, where it was placed upside down with a heavy stone on top of it. The stone weighed just under 9 kilos. When they lifted the stone, the bottom of the container came up with it.

The birch bark box (T13685) from Austrått.

Photographer is Ole Bjørn Pedersen, NTNU Vitenskapsmuseet, CC BY-SA 4.0

The bottom was quite well preserved and in one piece. The rest of the container was in a pretty bad shape, but they managed to restore it when it came to the museum, showing that it was about 20 cm in diameter and about 15 cm tall. The bottom seems to have been sewn to the walls of the container with natural fibers. The upper edge of the container was strengthen with a double layer of birch bark and sewn with thread made of fern. It is unknown whether the container once had a lid or cover of any sort.

Inside the birch bark container was a yellowish and soft substance, almost like a cream or butter, weighing 285 grams. This substance seemed to be well preserved. Analyzes made by the state Agricultural Chemical Control Station (done shortly after the discovery) showed that it most likely was butter or some other dairy product. Another test done shortly after the first test showed that it was a wax-like substance, like bee’s wax or honey.

The topographical conditions at the site indicated that the container had originally been placed in a small pond, known as ‘tjern’ in Norwegian. The heavy stone placed on top of the container could also support such a theory. The stone would in that case keep the container from floating up to the surface of the pond.

The birch bark container from Austrått have been dated to the transition between the Late Bronze Age and pre-Roman Iron Age, around 790–430 BC. At least two more birch bark containers have been found in mid-Norway dating from the same period. One was found at Torgård and another on Smøla. Other objects, such as flint tools, weapons and jewelries have been found in bogs all around Norway (and other places of course).

Also in Scandinavia and Europe wooden boxes or birch boxes similar to the one from Austrått with butter-like content, have been found. Several hundred is found only in Scotland and Ireland. Here they are often referred to as ‘bog butter’. For a long time it has been believed that people put the butter-like substance in bogs to preserve it or to give it a certain taste, but later analysis is showing that the containers often also contains animal fat or even animal meat.

Not so long ago they did some new tests on the substance inside the container from Austrått – this time with modern equipment and methods. This time they discovered that the substance was in fact a mix of bee’s wax, animal fat and betulin which is commonly found in birch trees. It is what gives the tree its white color which appears to protect the tree from mid-winter overheating by the sun. The amount of betulin found in the container was however too big to just come from the container itself so it must have been added to the substance.

The container from Austrått is one of several preserved depot finds made of organic material from central Norwegian bogs, which all have in common that birch bark is included as an essential component. One theory is that these containers were votive offerings put down in ponds to please the gods, similar to the flint tools, the weapons and the jewelry found in bogs. Others think that this was a common way to make butter, so-called bog butter.

Why do you think someone would put a perfectly fine birch bark container with content into a pond?

If you want to read more about this topic, there is a great article called ‘Stille vann har dyp bunn’ by Merete Moe Henriksen. This is the article I’ve used for my research.