Beer brewing in Sweden; as early as the Nordic Iron Age (500 BC–AD 1000), study finds

Archaeologists at Lund University in Sweden have found carbonised germinated grains showing that malt was produced for beer brewing as early as the Iron Age in the Nordic region (500 BC–AD 1000). The findings made in Uppåkra in southern Sweden indicate a large-scale production of beer, possibly for feasting and trade.

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“We found carbonised malt in an area with low-temperature ovens located in a separate part of the settlement. The findings are from the 400–600s, making them one of the earliest evidence of beer brewing in Sweden”, says Mikael Larsson, who specialises in archaeobotany, the archaeology of human-plant interactions.

Archaeologists have long known that beer was an important product in ancient societies in many parts of the world. However, as written sources in the Nordic region are absent before ca 1200 CE, knowledge of earlier beer production is dependent on botanical evidence.

“We often find cereal grains on archaeological sites, but very rarely from contexts that testify as to how they were processed. These germinated grains found around a low-temperature oven indicate that they were used to become malt for brewing beer”, says Mikael Larsson.

Beer is made in two stages. The first is the malting process, followed by the actual brewing. The process of malting starts by wetting the grain with water, allowing the grain to germinate. During germination, enzymatic activities starts to convert both proteins and starches of the grain into fermentable sugars. Once enough sugar has been formed, the germinated grain is dried in an oven with hot air, arresting the germination process. This is what happened in the oven in Uppåkra.

“Because the investigated oven and carbonised grain was situated in an area on the site with several similar ovens, but absent of remains to indicate a living quarter, it is likely that large-scale production of malt was allocated to a specific area on the settlement, intended for feasting and/or trading”, explains Mikael Larsson.

(Source: https://www.archaeology.wiki/blog/2018/06/21/swedes-have-been-brewing-beer-since-the-iron-age/)

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Abstract A metric analysis on hulled barley grain from the Iron Age regional centre of Uppåkra and surrounding sites in southern Sweden has identified a variation in the size of the grain found on these archaeological sites. Large, high-quality grain was found more frequently at Uppåkra when compared to sites in the surrounding area, where smaller grain was more frequent. The observed large grain found at Uppåkra was, however, restricted to only a few house contexts, including hall-buildings, while other contexts on the site, such as areas dedicated to craft production, had barley assemblages containing smaller grain, similar to the size range found on the surrounding sites. The intra-site variation between different contexts at Uppåkra points to a degree of sorting for larger grain and that this variation between grain assemblages was the result of selection after the crop processing was completed. The distribution of grain size at Uppåkra shows a pattern that indicates that the high-quality barley grain was indented for specific individuals or households. The different contexts at Uppåkra have together produced a record spanning the first millennium ad, representing almost the whole existence of the site. The evidence for selection of larger grain can be seen in the hall-buildings throughout most of the first millennium ad, although less prominently during the Late Roman Iron Age (AD 200–400), while during the Migration Period (AD 400–550) several houses on the main site Uppåkra had assemblages of large grain size. The distribution of grain size at the regional centre Uppåkra shows a pattern that indicates that the handling of large high-quality barley grain was part of a spatial organization, and such organization is similar to other functions observed on the site. The long-term record of grain size patterns across time shows that a structure for handling grain was already in place during the early phase of the settlement and that it remained for centuries. This study indicates that the affluence otherwise seen at the regional centre Uppåkra from an abundance of high-status objects, could also include agricultural wealth, with extensive access to high-quality grain.

(Source: “Barley grain at Uppåkra, Sweden: evidence for selection in the Iron Age”, by Mikael Larsson)

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Abstract The excavation of a low-temperature kiln structure at an affluent Iron Age regional center, Uppåkra, located in southern Sweden, revealed from archeobotanical samples and its context evidence of malting in the process to make beer. Carbonized germinated hulled barley grain (Hordeum vulgare) was recovered from the kiln structure itself and from the surrounding occupational surface. Located somewhat from the central area of the site, where previous excavations have uncovered hall-buildings, a ceremonial structure, and several smaller houses, the investigated kiln was situated in an area on the site that is absent of remains to indicate a living quarter. Activities using kilns have instead primarily been linked to this area and archeological finds are mainly of charred crops remains. In this paper, we argue that the germination of grain was deliberate and that the kiln was used to stop the germination process by drying or roasting the grain. If the malting process for large-scale beer production was carried out at a designated area of the site is discussed, as well as if this activity area was part of a structural organization observed elsewhere on the settlement.

Introduction Our knowledge of the preparation and consumption of beer in ancient times depends on archeobotanical evidence and non-botanical archeological evidence such as written and iconographical documentation. The importance of beer in society is well documented in inscriptions and legal documents dating back to the fourth millennium BC from Mesopotamian cultures (Wartke 1998; Damerow 2012) and ancient Egypt (Samuel and Bolt 1995; Samuel 1996, 2000). In Scandinavia, written and iconographical sources of beer are absent prior to the Middle Ages (before ca. AD 1200) and knowledge of prehistoric beer making is limited to finds of plant remains involved in the process of making beer.

The recently discovered germinated grain from the Iron Age settlement Uppåkra in southern Sweden (Scandinavian Iron Age 500 BC–AD 1000) presented in this paper provides evidence of malt from the fifth to seventh centuries AD and gives insights to the malting process in Scandinavian society. The Uppåkra settlement—a large affluent regional center during most of the first millennium AD—is thought to have had a spacial organization for several buildings, including hall-buildings, ceremonial houses, and workshop areas, as well as, grain storage and areas for ritual activities (Larsson 2011; 2015). The new find of germinated grain was recovered by a kiln structure, located in an area on the settlement with several other kiln structures, but absent of remains from houses (Stilborg 1998; Lindell 2001). Contextually, this indicates how the kilning in the malting process for making beer was an activity allocated to a specific area on the settlement and that it was part of the structural organization observed elsewhere on the settlement.

Archeobotanical evidence of beer making in prehistoric Scandinavia Prehistoric botanical evidence in Scandinavia for beer making is scarce and rests on a few finds of germinated grain and remains of beer-flavoring plants. The earliest evidence of beer making in Scandinavia have been recovered from Iron Age settlements and are assemblages of germinated barley grain, indicative of malt. At the Danish site Østerbølle dating to the first century AD, germinated grain was recovered from two ceramic pots from a burnt-down house, providing evidence of stored malt (Helbæk 1938). In Sweden, finds of germinated barley grain perceived to be malt were recovered from a stone ringfort site at Eketorp, dating to the sixth century AD (Helbæk 1966), and from a burnt-down ninth century AD Viking Age hall-building, where several liters of germinated grain was recovered (Viklund 1989).

Finds of the beer additive sweet gale (Myrica gale), a bush with its natural distribution in northern Europe, preceded hops (Humulus lupulus) in Scandinavia. Besides its use in beer, sweet gale was used in various fermented beverages dating back to the beginning of the first millennium AD in southern Scandinavia (von Hofsten 1960; Behre 1999; Balic and Heimdahl 2015). Hops are known in Scandinavia from Viking Age sites (ca AD 800–1050), but the plant increased in use first after ca. AD 1200, and later replaced sweet gale as an additive to beer (Jensen 1985; Hansson 1996; Behre 1999; Lagerås 2003: 256). From the Scandinavian Middle Ages (1050–1536 AD), medieval laws and written accounts are available to show the importance of beer in society, but provides also insights to the malting and brewing process, and beer additives used (Olaus 2010).

Site description Uppåkra is currently the largest Iron Age site known in southern Sweden. Archeological excavations and research based on its material culture reflects a wealthy settlement, thought to have served as a major economic and political center in the region during the Scandinavian Iron Age. (Hårdh 2001, 2003; Helgesson 2002, 2010; Stjernquist 2004; Watt 2004; Larsson 2007, 2011).

Site excavation Excavations at the Uppåkra site from 2013 to 2016 targeted the area with kilns previously investigated in the 1990s (Helgesson 1998; Lindell 2001).

Most of the archeobotanical remains were recovered in layer 119881, a mixed layer consisting of silt with fine charcoal and some fragments of burned daub that covered most of the investigated area. The layer was observed to be contextually contemporary with the kiln. Layer 119881 was partially investigated by excavating the layer in 1 × 1 meter units; a total of 20 m² was excavated from the layer.

Archeobotanical material and sample treatment Forty-four soil samples were collected and analyzed from the excavation area of the kiln. Sampling of layer 119881 was systematically done by collecting soil samples from every 1 × 1 meter unite during excavation.

Results

The botanical assemblage Twelve thousand seven hundred forty-four charred botanical macrofossils were recovered from the samples collected during the excavation. The botanical macrofossil material comprised cultivated plants and wild plants.

The cultivated plants were mostly cereal grain. Hulled barley (Hordeum vulgare ssp. vulgare) was the most abundant cereal, although significant amounts of rye (Secale cereal) were also present. While more limited in number, other crops recovered included emmerwheat (Triticum dicoccum), bread wheat (Triticum aestivum), and oat (Avena cf. sativa). A small number of chaff remains of hulled barley, rye, and wheat were found in the samples. Flax (Linum usitatissimum) and gold of pleasure (Camelina sativa) occurred frequently but in small numbers. Other cultivated plants are foremost associated with horticulture, such as herbs and spices, represented by finds of dill (Anethum graveolens) and black mustard (Brassica nigra). Finds of carrot (Daucus carota) typically represent a root vegetable.

Findings of seeds from wild plants include typical arable field weeds, such as fat hen (Chenopodium album), redshank, (Persicaria maculosa), common chickweed (Stellaria media), and black-bindweed (Fallopia convolvulus). Other seeds are typical of pastures and hay meadows, such as grasses (Poaceae sp.), ribwort plantain (Plantago lanceolata), fairy flax (Linum catharticum), common sorrel (Rumex acetosa), and red clover (Trifolium pretense). Alongside these were a range of plant species that can be associated with the local environment. Charcoal was found in all samples, but in small quantities.

Among the hulled barley recovered were a large number of clearly sprouted grains, in total 650. Evidence of germination was identified from morphological features on the grain, visible by development of the coleoptiles (shoot sheath or sprout) from the embryo, and by groove-like channels on the dorsal side of the grain.

Discussion

Botanical remains from the malting process Deposits of germinated grain are rare in the archeological record and make the find at Uppåkra of great interest. Sprouting can be triggered when suitable moisture and temperature levels occur and finds of germinated grain on archeological sites can originate from both accidental and deliberate circumstances (van Zeist 1991). Accidental germination could take place if grain was stored in damp conditions, or during wet summers, sprouting of the grain in the ear could have occurred. As a pre-treatment for beer brewing, germination was induced intentionally in the process to make malt by wetting the grain. Germination activates enzymes that covert the starch of the grain into digestible sugars. Other uses of germinated grain, even if less common, has been for various dietary uses including eating the malt raw or used to make bread (Bouby et al. 2011). Parts of the wort from the beer brewing could be used and added to the bread dough to make a sweet bread.

The germinated barley grain found in this study at Uppåkra are thought to be relevant to the kilning in the malting process and represent the first stage in the making of beer. The clearly germinated grain is relatively low in number compared to ungerminated barley grain found from the excavation. A low quantity of germinated grain in an assemblage could be the result of accidental germination and represent grain being dried to halt further spoilage of a crop. An arbitrary percentage of germinated grain in such grain assemblage has been estimated to be less than 15%, while an assemblage with germinated grain above 75% is regarded as a reliable evidence of malt (van der Veen 1989). Sound evidence of malt, such as the finds of thousands of germinated grain found at Hochdorf in Germany (Stika 1996) and Østerbølle in Denmark (Helbæk 1938) consisted almost entirely of germinated grain. These finds of malt represent a single depositional event as preservation occurred after a batch of germinated grain accidently got charred during the kilning process or carbonized during storage from a house-fire. The germinated grain found at Uppåkra are, in contrast, not a closed find from a single event, but occur spread out around the kiln and in the kiln itself, probably as spill accumulated from several roasting events of green malt. It is likely that occasionally, some grains close to the heat source got charred when green malt was placed to dry and be roasted by the hot air in the kiln. After repeated use of the kiln for roasting malt, rake-outs and cleaning from several firings could produce spill of germinated grain around the kiln and explains the low percentage of germinated grain in the investigated context.

Germinated grain recovered in layers pre-dating the investigated kiln and the contemporaneous layer 119881—remains from a presumable older kiln structure and the occupational layer 116178/117705—show chronologically different depositional contexts of malt across time. This points to a continuity of malting that can be traced to this area of the site.

Malting and spacial organization Hall-buildings, several smaller houses, and workshop areas have over the years been archeobotanically investigated at Uppåkra, while to date, remains of germinated grain are restricted to the recent finds presented in this paper. Subsequently, the finds of germinated grain in the context of the investigated kiln, probably from activities of kilning malt, suggest that steps in the malting process for making beer was allocated to a specific area of the settlement. Probably, there might have been malting also in household level; however, that is much more difficult to detect, if normal hearths were used to dry malt in small scale.

In line with previous observations for some fixed building patterns and functions on the site, it is probable that also kilning to produce malt was carried out at a designated area, and for as much as several centuries. If so, this points to a specialized malting activity in this area of the settlement, and in contrast to household level, this was likely aimed for large-scale beer production. With the status of the Uppåkra site as a major economic center in the region, it is possible that large-scale beer production was intended for feasting or/and trade.

Conclusion The carbonized germinated hulled barley grain found in the excavated area of the kiln structure have proved a contextual relationship to indicate that the low-temperature oven of the kiln was used for drying and roasting germinated grain to produce malt used for making beer. The recovered germinated grain is rather low in quantity but reflect accumulated spill from repeated heating events. Germinated barley grain was found also in layers predating the investigated kiln, suggesting continuity across time of malting at this location of the site. To date, germinated grains have previously not been recovered from households archeobotanically investigated at Uppåkra. This indicates that kilning in the malting process was an activity allocated to a certain area of the site, likely produced in large scale intended for feasting and/or trade.

(Source: “Botanical evidence of malt for beer production in fifth–seventh century Uppåkra, Sweden”, by Mikael Larsson, Andreas Svensson & Jan Apel)

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Research-Selection for NovoScriptorium: Philaretus Homerides

 

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