Genbesøg på Bjørnkær

Resumé

Bjørnkær revisited
A new evaluation of the distillation set and large grain deposit

The well-preserved castle mounds of Bjørnkær, situated in Gosmer parish, near Hou in eastern Jutland, were excavated in the early 1930s by the local doctor Jens Didriksen under the supervision of architect C.M. Smidt of the Danish National Museum (figs. 1, 2, 5). During the investigation of the site, dated typologically to the 13th or 14th century AD, several important finds were made. Of these, the remains of a probable distillation set surrounded by an estimated 150-200 l of partially charred grain, deposited in a well in the southeast corner of the castle cellar, were of particular interest (fig. 3). When the pottery distillation set was reassembled, it was found to consist of 35 unique funnels, pans, lids, vessels etc. It was interpreted by the excavator as having been linked to the grain, which Didriksen believed had been used to produce alcohol in the set. The Bjørnkær distillation set is the oldest of its kind found to date in Denmark (fig. 4).
A major problem regarding the interpretation of the Bjørnkær site has long been that the excavation results were never thoroughly examined and presented after the conclusion of the excavation. Consequently, the various interpretations of the findings have been considered uncertain on several points. One such uncertainty relates to the dating of the distillation set, so far fixed as the late 14th or early 15th century AD, based solely on typology. Another uncertainty results from the composition of the grain find never having been thoroughly investigated. It was merely assessed in the 1930s by Knud Jessen, with the result then being published by Didriksen. At this time, Jessen was professor of botany at the University of Copenhagen as well as being the director of the Copenhagen Botanical Garden. According to Didriksen, Jessen assessed the grain deposit as being mainly composed of a mixture of naked and hulled six-row barley but also with some oats, as well as rye, vetches and wild plants. Regarding the latter, Didriksen notes that there were many seeds of wild radish, corncockle, cornflower and fat hen.
The main aim of the studies presented in this article has been to confirm or discount the previous interpretations with regard to the dating of the distillation set and the composition of the grain deposits by obtaining 14C dates and undertaking a thorough analysis of the grain. In addition to a small cardboard box containing handpicked carbonised grain and wild plant remains of unknown origin, there is also a bag containing 1805 ml carbonised material from the original grain deposit found in the well; the latter has formed the basis for the current analysis. A secondary aim has been to discuss whether the grain found in the well was actually intended for alcohol production. This is not given since medieval distilleries were not used solely for alcohol production but also for other purposes like alchemical experiments.
The 14C dates which, due to a lack of preserved organic matter on the distillation set itself, were based on two grains of hulled barley (Hordeum vulgare var. vulgare) and one grain of oat (Avena sp.) from the grain deposit, lay within the range AD 1303-1423 (95.4%) or AD 1320-1411 (68.3%), thereby confirming the typological dating of the find.
The results of the archaeobotanical analysis, presented in table 1 and on figures 6 and 9, show that the composition of the grain deposit corresponds to Jessens results in some ways but deviates in others. It is assumed that the differences are likely due to Jessen having assessed material from another part of the deposit than that analysed in the current investigation. This cannot, however, be verified due to the absence of the remainder of the original grain deposit. Regarding the similarities, large amounts of barley grains and the presence in smaller amounts of grains of oat and rye (Secale cereale ssp. cereale) were recorded in both analyses, as were numerous seeds and seed pod fragments of wild radish (Raphanus raphanistrum) and seeds of cornflower (Centaurea cyanus) and fat hen (Chenopodium album). Dissimilarities are especially evident in the presence of bread wheat/durum wheat (Triticum aestivum ssp. aestivum/Triticum turgidum ssp. durum) and large amounts of cabbage/mustard/turnip etc. (Brassica sp.) seeds recorded in the current analysis. These were not found in the previous assessment, while corncockle (Agrostemma githago) and large amounts of vetch (Vicia sp.) seeds and grains of naked barley (Hordeum vulgare var. nudum) were only recorded by Jessen in his original assessment. The complete lack of naked barley in the new analysis is an important difference as Jessen’s record of this species is highly unusual. There are virtually no other records of naked barley in Danish archaeobotanical finds from the Middle Ages, and its absence in the small proportion of the Bjørnkær material that remains today unfortunately makes it impossible to confirm its presence via a new thorough analysis.
The plant species present and the overall composition of the plant remains revealed by the current analysis are very typical for medieval finds from Denmark. The grain deposit apparently consisted primarily of hulled six-row barley, probably of the lax-eared variety (figs. 7 & 10), but it also contained minor presences of other grain species. The latter likely either represent grain that had become mixed with the barley in the well or plants which had grown together with the barley in the field. Wild plants are also represented, especially typical weeds, which had probably mainly grown and subsequently been harvested together with the grain. Seeds and fruits of wild plants constitute 19% of the find by number (fig. 9). This is a relatively large proportion, but as there are no certain presences of straw fragments, rachis internodes or remains of glumes, the barley grain had probably still been processed and cleaned to some extent.
As for the functional connection between the distillation set and the grain found in the well, it is argued that this cannot be established with certainty. Even though the distillation set and the grain were found together, they may originally have been deposited separately in the castle. During the analysis of the Bjørnkær find it was noted that no grains showed evidence of sprouting, which is a sign of malting. Sprouted grain can often be found during archaeobotanical investigations of medieval grain deposits associated with breweries. If sprouts had been present on the grains, this would have reinforced the idea of a potential connection between the grain and the distillation set.
Distillation of alcohol based on grain is believed to have begun in Denmark around the end of the 14th century AD. It must therefore be concluded that, although the intended use of the grain found in the well may have been alcohol production, a connection between the grain and the distillation set cannot be made with certainty. A likely interpretation of the grain is that it was stored somewhere in the castle where it was used for various everyday purposes that may or may not have included alcohol production. After carbonisation, which most likely happened due to an accident involving fire, the grain was subsequently deposited in the well together with the distillation set.