Saturday, 15 August 2020

origins of grain agriculture: some thoughts from a brewer

This is written by Graham Dineley, an all grain brewer for almost 40 years now. All ideas, opinions and mistakes are my own.

The widely accepted view of the first grain farmers of the Fertile Crescent is that they grew the grain to grind into flour to make bread. Grain was a staple crop that would see them through famine and hard times. Being a brewer I have a different perspective on grain. When I look at a field of grain I see the potential for malting and brewing beer. When non brewers look at a field of grain they just see flour and bread.

The homeland of the grains such as wheat, einkorn, barley etc. is Anatolia and the Levant. Deep in the last Ice Age, when Britain and northern Europe was under kilometres of a huge ice sheet, the people living in the Fertile Crescent were hunting, fishing and gathering wild seeds and plants. They lived in caves, for example, the Shanidar Cave.

Excavations by Ralph Solecki at Shanidar Cave, in the mountains of Kurdistan, revealed that it was inhabited for thousands of years from the Palaeolithic onwards. 
What were they doing with the grain? How did they discover malt? The earliest scientific evidence for malt in the Fertile Crescent dates to c13,000 years ago according to research by Professor Li Liu and her colleagues of Stanford University. Malting and making malt sugars from the grain is an ancient technology. 

Grain, when it is still green on the ear and not yet quite ripe is slightly sweet. Sweet enough to be attractive to eat. This is confirmed by our own bere crop. We have tasted the unripe green grain, it was sweet and grassy. Ripe grain is hard, difficult to chew and not sweet. If these people gathered the ripe grains and stored them, they may well have wetted them to soften them. This would start the germination and would again make them slightly sweet. They could easily have then dried these damp slightly sweetened grains in the sun for storage, if left undried the grain would spoil.

Now for the trick.

If they had started germinating them and there was period of heavy rain and no sun lasting for days, then I could imagine that they could take the grain into the cave and spread it out on the floor to dry. It would, of course, not dry but they may have continued turning the grains in an attempt to dry them, until the sun returned. This is essentially floor malting. It is the trick that is often overlooked by many archaeologists in the literature. Malt is usually described as sprouted grain, which it is not. In 2019 Merryn was invited to attend a workshop: Ancient Beer in Europe. It was organised by a number of archaeobotanists from around the world and an image of sprouted grain was used in the promotional material. See below. Merryn was unable to attend the meeting due to illness and so she was unable to present her paper on malt, malting and traditional techniques of making malt sugars. Her paper was read in her absence by one of the participants. She is in the process of writing it up.  

This image is of sprouted grain. It is not malt.

 This is brewers malt. Courtesy Wikimedia.
Any growth of the grain is from starch turned into sugars, which in turn is converted into cellulose. When grain has sprouted to the point of having green shoots, it has lost potential sugars. Malt is fully germinated grain with minimal growth. In all the literature that I have read, including that by maltsters, the turning and raking of the malt is to prevent the roots from tangling. I have seen unturned malt in the corners of a malting floor and it is indeed matted, with both roots and shoots, greenish in colour.

I think that the turning and raking of the malt confuses the geotropism of the shoots. The poor shoots are desperate to grow upwards, but never get chance to find out which way is up, so they don't grow. The grain continues to germinate for the next 3 to 5 days until complete conversion of the grain is achieved, normally with minimal sprouting. The shoots are less than the length of the grain.

Inside the grain alpha and beta amylase enzymes have been produced in the aleurone layer and just underneath there are erosion pits in the starchy endosperm. Merryn has some scanning electron microscope pictures which show this. They were taken for her research funding bids between 2000 and 2004. The grains were 6000 year old carbonised grain from the excavations of a large neolithic rectangular timber building at Balbridie, Scotland. There were thousands of grains and Professor Ian Ralston gave her six to examine. They were scarcely bigger than grape pips. More on this in a later blog.

The proteolytic enzymes that are also produced have degraded the protein matrix that binds the starch granules into a hard grain. Once properly converted and dried, gently, so as not to degrade the alpha and beta amylase enzymes, we have malt. This has completely different properties to unmalted grain. It is friable and easily crushed to release malt flour. No grinding is needed, just a flat stone and a pounder.

This turning and raking of the germinating grain is such a clever trick, like fire lighting, that once discovered it would never be forgotten. A perfect tool for manipulating the grain like this is a scapula. However, inhibiting sprouting fails at temperatures close to and above 20 degrees Centigrade in the malt bed. This is why traditional floor maltsters did not make malt when there is no R in the month name. An exception to this are the caves at Nottingham, England, which have a low constant temperature. Malt was made all year round in medieval times and earlier. A cave is an ideal place to make malt.

Interestingly a scapula was found in one of the large stone cisterns at the epi Palaeolithic site Gobekli Tepe. One was also found in the Bronze Age "food vessel" cist burial of a young woman at Achavanich, Scotland. The original interpretation of the residues in this beaker by Moffatt was one of a grain based beer, the earliest evidence for beer in Scotland. See our blogs on 'Beakers were for beer' parts one, two and three for more details. 

I think that sometime before 23,000 years ago the seed gatherers of the Fertile Crescent had cracked the trick of malting by turning the damp grain on the floors of caves with scapulas. They could then have made sweet malty biscuits. Merryn has done this on hot stones beside a fire. These "malt cakes" are sweet, tasty and attractive, far nicer than bread. She made some at a demonstration of "mashing in" techniques at the Eindhoven Open Air Archaeology Museum in 2009. They were quickly consumed by the visitors.

Demonstration: making sweet malty biscuits on hot stones beside the fire. Mashing in an earthenware bowl. It's easy to make fermentable malt sugars from crushed malt.
There is a site called Ohalo II on the shore of Lake Galilee where excavators found traces of starch granules on a large rock and fire blackened stones nearby. They interpreted this as bread making. As far as I know, they did not look for morphological changes in the starch granules consistent with malting like Professor Li Liu did at Raqefet cave.

Once the art of malting and making sweet biscuits on hot stones has been mastered, fermentation by serendipity only requires some sort of container and water. At Gobekli Tepe, an epi Palaeolithic site in Turkey, they found limestone cisterns cut from rock. When I first saw a photo of one of these cisterns in a journal article, it had a few rocks in the bottom. I emailed one of the excavators Jens Notroff and told him that I thought that this was a hot rock mash tun and they were making beer. I asked whether they had found any cisterns with small holes in or near the base. He replied that they had not, as yet.

I was wondering how these people could be lautering and sparging their mashes to obtain a wort. It was also a puzzle to me when we demonstrated a hot rock mash at the replica burnt mound trough on Bressay, Shetland. When I read Lars Marius Garshol's work and learned about kuurnas the problem was solved.

A kuurna, photo by M. Rasanen 1965, courtesy of Lars Marius Garshol

There is a burnt mound trough at Nant Farm, Porth Neigwl, Gwynedd, Wales, where they found piece of a sewn plank boat in the trough. This could be the remains of a kuurna. What better place to store one. A kuurna made from a log would leave no archaeological evidence, except when someone is buried in one and it is interpreted as a log coffin, as at the  Egtved burial.

By the time of Gobekli Tepe, people were gathering wild grains and processing them into malt and ale for their feasts. This was winter cereals, gathered in late spring and consumed in the summer.

Then came the Younger Dryas changing the climate to a cooler condition when these cereals would no longer grow in sufficient quantities for their purposes and cultivation of cereals began. Interestingly this was caused by the impact of  bolides in North America and Northern Europe. Professor Mike Baillie has proposed, over 20 years ago, an interesting theory that many climate changes have been caused by passing comets, bolide impacts and bolide air-bursts.

So the answer to the great 1953 "bread or beer" debate by Braidwood is neither. It was malt and malt sugars, as Merryn argues at the end of her Master's thesis. This was published as a BAR by invitation in 2004.

Further reading
These books have been very useful in our understanding of the science and practicalities of malt, malting and wort production. Rather expensive to buy but they should be available through inter library loan and are to be found in many University libraries.

Bewley, J.D. and Black,M. 1985 Seeds: Physiology of Development and Germination. Pub Plenum Press
Second Edition 1994 see in particular Chapter 8

Briggs, D. E. 1998 Malts and Malting. Pub Springer

Briggs, D.E., Stevens, R. and Young, T. W. 1981 Malting and Brewing Science Volume 1: Malt and sweet wort. Pub Institute of Brewing.

Stopes, H. 1885 Malt and Malting: An Historical, Scientific and Practical Treatise Pub Lyon
This has been scanned in by the University of Oxford library. It is available to read online here:


  1. Graham, Sparging is relatively modern technique in beer brewing. It only appears in England in the 18th century and requires a separate vessel in which to heat the sparge water. Prior to that the first wort would be drained off the grain and a second lot of water added to create a second, then third and even occasionally fourth wort. (The last two were usually made into small ale in the medieval period.) Medieval brewers preferred to leave a little bit of sugar in the spent grain otherwise it lost it's nutritional value as animal food.

    My personal theory is that prehistoric brewers meerly had to bail wort from their mash tun with a hand held bowl, and strain it through a pad of herbs into a fermenting vessel. Herbs, particularly Umbelliferae carry a lot of yeast spores and would have suffused the wort with yeast as well as adding extra flavour. The strained grain could then be returned to the mash tun, more water and hot stones added and subsequent mashes made on the same grain.

    1. Hi Belle, I have added a picture of a kuurna, for those that do not know what one is.I think you have to bail the mash into the lautering tun or kuurna that holds the bed of herbs, often juniper branches. I don't think you can strain wort through a pad of herbs alone. Have you done it? I would be very pleased to hear about it.
      Personally I do not trust to wild yeasts. In my experiments my wort was already infected and needed a vigorous starter to overcome those infections.