Friday, 27 February 2015

Mesolithic cereal trade in Europe?

This week's Science includes in ancient sedimentary DNA study by Oliver Smith, Robin Allaby and colleagues from sediments from an archaeological site sealed beneath the English Channel, with evidence that wheat was decomposing on this Mesolithic site 8000 years ago. Such a claim is obvioulsy a big deal for archaeologists, it is counter to our accepted narrative of the introduction of cereals with Neolithic farming immigrants around 6000 years ago. No surprisingly it has received science media attention, both in Science and in New Scientist, as well as a learned commentary from Gregor Larson; and despite a busy teaching week I have been asked for comments. Here I give my full extended comment. While I agree that we really need more evidence to clinch this from additional sites, and I would prefer directly radiocarbon dated grains, I also don't think this requires a complete overhaul of what we know about the introduction of sustained farming around 4000 BC.

This paper is methodologically impressive. They have developed a robust phylogenetic approach to cautiously ID sedimentary aDNA. The deposits seem well dated and sealed by rising sea-levels. So we are left with the challenge of fitting this to our world view as archaeologists. 

This report is sure to be heavily debated, and I guess many archaeologists will reject this out of hand. But that is perhaps like the ostrich with its head in the sand. I would certainly be happier with an AMS-dated cereal grain, but this new evidence tells us we need to be actively looking for those Pre-Neolithic traded grains.

I suppose this will reopen the debate about claims for Mesolithic cereal pollen grains, which have been claimed from sites here and there in Britain and France. Most archaeologists have rightly tended to follow the critical assessment of these, represented for example by the writings of Prof Behre, a senior archaeobotanist and doyen of anthropogenic pollen indicators (e.g. Behre 2007). I expect new scrutiny of such finds, as they could also relate to a pioneer phase of small scale cereal adoption.

From Larson 2015
This find does not mean the Neolithic needs to redated. The Neolithic in Britian is well dated to about 4000 BC which sees a rapid rise in human population together with evidence for emmer wheat, barley and livestock. This follows a spread of agricultural populations, uniformly with big demographic booms across central and western Europe (e.g work by Shennan et al. in Nature Comms, 2013). This I think is still clear. But the New wheat DNA from the English channel requires us to think in terms of small scale pioneers operating beyond the frontier of farming spread and trading with Foragers, and beyond that foragers trading with each other. Mesolithic foragers were well adapted to their environments given their population density so this would not have been about trading food as needed calories but about foodstuffs that were rare, exotic and valuable. I would guess these early cereals would have been symbolically charged as exotica much like spices in much later times. In regions with obsidian we know Mesolithic populations had long distance trade networks. This new evidence suggests long distance networks also moved perishables, including edibles.

I think we can see this as on par with the food "globalization" episodes in much later prehistory, such as the Bronze Age. When sorghum and other African crops arrived in India 4000 years ago, or wheat arrived in China in the third millennium BC, these edibles proceeded any other material evidence for trade. This implies long distance small scale exchanges in exotica, including what seem to us today as mundane edibles, were highly valued, presumably in part because of the symbolic associations with distance and the exotic. I have written about this in a few places, e.g Fuller et al 2011 in Antiquity or Boivin et al 2012 in World Archaeology (blogged here).

So perhaps what we are seeing is evidence for an early Holocene equivalent-- the Neolithic grain as the tastey exotica in a the Mesolithic world


Marc Dineley said...

There is a very easy way to make mundane cereals into exotica. First malt them, then mash them into sugars, wort, and then ferment that into ale, a status product. It is very difficult to explain this to archaeologists though, as it is entirely absent from archaeological literature. This I believe is because the famous archaeobotanist, Gordon Hillman, did his fieldwork in Turkey, a moslem country, where such practices were proscribed some 1200 years ago.
Archaeologists may begin to understand the "first farmers" better when they become aware of the potential for cereals to be a status crop rather than a staple. See

Dorian Fuller said...

As attractive of Dineley's comment may be as an idea, it unfortunately is not supported by any good hard evidence. Malted grains take on a charactieric morphology as their dorsal side becomes furrowed (as the sprout starts to consume the starch in the grain, and the underlying seed starts to desolve beneath its pericarp from the back and tip). As malts are often roasted accidents are likely. Good examples of such cereals come from Iron Age and Roman periods in Britain and Germany (see. e.g. Stika et al 2011 in Archaeol Anthropo Sci. 3(1)), but I am not aware of any such assemblages from the early Near East. Sites like Catal Hoyuk where literally millions of seeds from flotation have now been studied, where morphological preservation is excellent, could be expected to product such assemblages, but have not. Instead, at Catal and many earlier Pre-Pottery Neolithic sites in the Near East one is struct by the ubqituiy of gridning stones (for making flour) and ovens, for bread. Every house has an oven. This is a early world of bread not beer. Elsewhere in the world where early food processing focuses on pottery (e.g. Nubia and the Sahara where pottery is earlier than farming, or East Asia), fermentation is much more likely.

It is wrong to imply that Gordon Hillman overlooked brewing, its just the cereal assemblages he worked on (Can Hassan in Turkey in the 1970s) did not produce cereals with indicated having been germinated (malted).

Merryn Dineley said...

Thanks a lot for replying to the comments my husband (the brewer) made earlier about the exotic potential of malt. He's interested in the fermentation; he makes the ale. My area of research is the archaeological evidence for malt, the equipment and installations necessary for malting and the biochemistry of grain germination physiology.

You mention roasted malt. This is an invention of the 18th Century AD, when maltsters began to use high temperatures in the kiln to make dark malts for colour and flavour. Hence Porter.

Roasted malts make up no more than 10% of the mash tun, providing flavour and colour to the brew. They do not provide any sugars.

Malt is dried gently, so that the enzymes are not destroyed. In cold climates a low temperature kiln is necessary. Malt is dried gently over several days. In hot climates, it is possible to dry the malt in the sun.

Early quern stones are just as useful for crushing malt as they are for grinding unmalted grain into flour for bread.

I think that the question is not 'bread or beer' but who were the first maltsters?

Merryn Dineley said...

It would be great to have a proper discussion about malt and malting in prehistory one day. I think it is a fascinating and important ancient technology, one that goes right back to the origin of grain agriculture. I have a paper about the craft of the maltster, it will be published soon and can be downloaded from my academia page. I'd welcome your comments on it.

Roasting the malt kills the germ and it is not possible to make malt sugars or beer with it. It is used as an adjunct, adding only colour and flavour. To make fermentable sugars the malt must be dried slowly and gently.

Here's a link to the rather interesting story of roasted malt, a relatively modern phenomenon.

Dorian Fuller said...

Useful comments. Thanks. I am.sure fermentation is an ancient technology but I must return to the lack of archaeological and archaeological evidence for early periods I. The Near East. This suggests it is not common or routine. Archaeology is very good at recovering the routine, and the evidence we have points to routines of cereal processing for clean edible grain or flours and breads.

Merryn Dineley said...

I don't understand why the suggestion of making malt, malt sugars and ale from the grain in the early neolithic is such a controversial and unacceptable topic for archaeobotanists and archaeologists. Maybe it is because they don't understand what malt is, how it is made or what its' role is in the manufacture of malt sugars, ale and beer. Much of the scholarly literature about malting is incorrect.

I have to disagree with you, Professor Fuller. There is a great deal of evidence for malting and the transformation of grain into fermentable sugars and ale in the neolithic. It's important to understand the processes. A quern stone is just as useful for crushing the malt as it might be for laboriously grinding the grain into flour. A kiln can be used to dry the malt (at low temperatures) when it has begun to germinate on the malting floor. In sunny climates, malt can be dried in the sun. Large buildings with smooth, deliberately made floor surfaces (clay or lime plaster) are ideal as malting floors, where the steeped grain is laid out to begin germination.

Malted grain has very different properties to unmalted grain. It is friable and easier to crush. You can make very fine flour with it. Malted grain is easily transformed into fermentable sugars. I have made bappir (aka sweet barley cakes) on a hot flat stone by a fire. The ingredients were crushed malt and water. Wort is made by heating the crushed malt with water in a container.

I would be happy to give a practical demonstration, a talk, seminar or workshop at UCL or any University to explain these fundamental grain processing techniques - malting, mashing and fermentation. In the meantime, there are photos on my blog (ancient malt and ale) and plenty of papers on my academia page.

Practical demonstrations are the best, though. I'm happy to answer any questions you have.

Merryn Dineley said...

Sorry, the link at the end of my comment above does not work. It was supposed to connect to a recent post on my Facebook page - "Ancient Ale: recipes techniques and traditions". I am sure it is not too hard to find.

andrew said...

One of the readers at my blog (discussing this post) asked the question about leavened v. unleavened bread.

Leavened bread, of course, requires yeast, while unleavened bread can be made without it. Yeast chemistry in bread making more naturally links to beer making.

Do we have any evidence for when leavened bread started to be made and how that related sequentially to beer making?