2006 The Use of Spent Grain as Animal Feed in the Neolithic more

Merryn Dineley Spent Grain as Animal Feed in the Neolithic 2006, revised 2010 The use of spent grain as animal feed in the Neolithic Merryn Dineley revised February 2010 This paper was first published as Chapter 6 in ‘Animals in the Neolithic of Britain and Europe’ Neolithic Studies Group Seminar Papers Volume 7, edited by Dale Serjeantson and David Field, 2006. It was not possible for colour images then, so I have added some here. Since publication of this paper, I realise that not everyone knows what ‘spent grain’ or ‘draff’ looks like. Some people think it is the stalks and chaff left over from threshing; it is not. Spent grain or draff is the residue from the mash tun, after the wort or liquid malt sugars have been extracted from the mash. It is made up of soft grain husks; it is still slightly sweet. It is used as animal feed, usually for cattle or pigs. Goats like it; but, strangely, sheep do not. Birds, slugs and worms eat it, so the chance of any being left in the archaeological record is unlikely. 1 Merryn Dineley Spent Grain as Animal Feed in the Neolithic 2006, revised 2010 Above, spent grain, draff or brewer’s grain, the leftovers after mashing and sparging. Perfect fodder for pigs, cows, goats, but, strangely, sheep do not seem to like it. Birds, slugs, snails and worms eat it. It is slightly sweet, still, but is not alcoholic. It will certainly not ‘make the pigs drunk’, as has been suggested to me several times at Conferences by people who do not understand the brewing process. Introduction The practice of animal husbandry was introduced into the British Isles, together with cereal agriculture and pottery manufacture, around 4000 BC. These new skills and specialised crafts changed the lives of the Mesolithic population and originated in the Fertile Crescent several thousands of years earlier, spreading across Europe and into Britain as part of an integrated holistic and developed package. The newly introduced cereal crops were cultivated and processed in a variety of ways for both humans and animals to eat. There is some evidence that, during the Neolithic, branch foddering may have been one way of feeding the livestock (Rasmussen 1993; Akaret & Rentzel 2001). Grazing would also have been available in the spring, summer and autumn. But what food would cattle have eaten during the long, dark, cold months of winter? This paper investigates the possibility that spent grain or draff was available for use as animal feed in Britain during the Neolithic. In order to make this assessment it is necessary to explain malting, mashing and sparging in some detail so that it is clear what spent grain is and how it is produced. Oats, barley, wheat and rye - different grains for different products. There are many different products that can be made from cereals. Grain products should not be confused with oat based products. Porridge or gruel are made by cooking or simmering oats with water or milk. Unprocessed wheat and barley are not digestible 2 Merryn Dineley Spent Grain as Animal Feed in the Neolithic 2006, revised 2010 and so these grains must be processed in some way. It has always been assumed that, in the Neolithic, the grain was ground into flour, using saddle querns to make bread. However, wheat and barley can be partially germinated, a process known as malting. This breaks down the husk and endosperm, making the malt soft, friable and very much easier to crush than unmalted grain is to grind. Malt is easily crushed using a saddle quern. It will naturally produce malt flours which, when baked, will always produce a sweet product because of the presence of starchconverting enzymes. Crushed malt can be mashed and wort (liquid malt sugars) are produced. This can be consumed immediately, mixed with milk to make a nutritious malted milk drink or it can be fermented (Lewis & Young 1995, Hough 1985). The byproduct of this kind of wet processing for sugars is the draff or spent grain, that is, the husks and insoluble fibre of a sparged mash. Brewer’s spent grain has been used as animal feed for many hundreds, if not thousands, of years. It is rich in moisture, proteins, minerals, lipids and it is a good source of dietary fibre (Hernandez et al 1999). It is slowly digested by the animal, making it ideal as a winter feed. The ancient crafts of malting, mashing and sparging. Malting Malting is an ancient and traditional craft whose origins are lost in the mists of time. Today most people are unaware of what malt is and few people know how it is made. Malt is, quite simply, partially germinated grain and any grain can be malted. Barley is the most common grain to be malted because it produces the most sugars, although wheat can also be made into malt (Hough 1985). Traditional malting methods involve first steeping the grain in water for 2-3 days. It must also be aerated for the germination process to begin. The wet grain is spread out in a layer 4-6 inches deep on a smooth, level floor surface in a dark, well ventilated building (Figure 6.1). The gradually germinating grain is raked and turned regularly until the green roots and shoots are visible. This takes between 4 to 7 days, depending upon ambient temperatures. Figure 6.1: Diagram showing what happens inside the grain whilst it is beginning to germinate on the malting floor. Giberrellin, a growth hormone, is released by the embryo. It acts as the inducer and its presence allows the enzymatic induction of amylase, an enzyme which breaks down starch into sugars (after Bewley and Black 1994). See also http://www.ukmalt.com/howmaltismade/maltmade.asp Germination makes the grain soft and friable. The ‘green’ malt is gently dried in a kiln, as temperatures above 67 degrees centigrade will destroy the enzymes produced during 3 Merryn Dineley Spent Grain as Animal Feed in the Neolithic 2006, revised 2010 germination. The same kiln can be used to dry harvested grain prior to storage for later malting. Dry malt stores well and is, therefore, available for processing all year round. Scientific understanding of the biochemical processes involved in grain germination continues to improve and evolve. Modern technology has changed the way things are done but the basic process of germination remains the same as it ever was (Lewis & Young 1995, Hough 1985). The malting industry has benefitted from scientific research and recent technological advances. Today there are only a few malting companies left in Britain that still run a traditional floor malting facility, one of these being Fawcett’s Maltsters of Castleford (see below). The others are Crisps Maltings and Warminster Maltings. Only 0.1% of all malted grain that is now made in Britain has been floor malted in the traditional way. The rest is made in modern stainless steel germinating/kilning vessels. Traditional floor malting at Thomas Fawcett’s & Sons, Castleford, Derbyshire. The germinating barley is raked and turned to keep it fresh. Other floor maltsters still operating in the UK are Crisps Malting Group and Warminster Maltings. http://www.crispmalt.info/ http://www.fawcett-maltsters.co.uk/ http://www.warminster-malt.co.uk/ Mashing To make a sweet barley mash, the crushed malt is mixed with hot water. The malt must be crushed so that the constituent parts, that is the starch from the endosperm and the enzymes from the aleurone layer that have been activated by germination, are intimately mixed and continue the conversion from starch into sugars (see Figure 6.1). It is a simple, straightforward process to successfully mash the crushed malt and water in a pottery bowl (Dineley 2004). I began my experiments in mashing using beeswax or fat sealed pots in 1995 and I have given demonstrations recently – the technique works every time. There is a characteristic sweet, pungent, aromatic smell that is easily recognisable when the enzymitic conversion from starch to sugar begins. The optimum temperature for the mash is between 65-67 degrees Centrigrade. At these temperatures the enzymes make the best conversion from starch to maltose and the 4 Merryn Dineley Spent Grain as Animal Feed in the Neolithic 2006, revised 2010 process results in liquid malt sugars being liberated from the malt. It is possible to mash using earthenware vessels that have been sealed with animal fats or beeswax. (Dineley 2004). Practical work shows that gentle heating of crushed malt and water always produces a sweet mash and liquid malt sugars. This is not to be confused with porridge or gruel. It is an entirely different product and process; it is an enzymatic reduction not cooking process. Sparging The sweet liquid or wort is run off. More wort can be washed from the mash by simply pouring hot water through it and collecting the run off in a large vessel beneath. This is called sparging. The resultant liquid, the wort, is an excellent nutritional food resource in its own right (Vietor and Voragen 1993). Once most of the liquid sugars have been sparged from the mash, what remains is the spent grain or draff. It is at this point that the fatty barley lipids are mobilised by the hot water. Barley lipids and ‘unidentified sugars’ have been identified on Grooved Ware pottery at the Neolithic village of Barnhouse., Orkney, Scotland (Jones 2002). The barley husks and insoluble fibre left after sparging, makes excellent fodder for both ruminant and monogastric animals. It is slightly sweet and contains high levels of protein, dietary fibre, lipids and vitamins. Nutritional properties of spent grain or draff The nutritional qualities of spent grain, sometimes referred to as brewers’ spent grains or draff, are now well understood (Hernandez et al 1999). Although the composition varies with the particular barley variety, spent grain contains moisture, cellulose, proteins and lipids or fats. It is suitable for dairy and beef cattle, pigs and goats (Santos et al 2002). The energy in spent grain is derived from the fibre and fats rather than from starch or sugars, for there is very little of this left after processing. This energy is absorbed by the animal over a prolonged period of time. Spent grain, draff, brewer’s grains – whatever you call it, the animals will eat it. 5 Merryn Dineley Spent Grain as Animal Feed in the Neolithic 2006, revised 2010 Spent grain is, therefore, a useful, nutritious and versatile source of animal feed. It can be given to the animals on its own or it can be added to poor forage or dry fodder in order to make them more succulent and palatable to the animal. Quite a versatile by product of brewing. Feeding animals in Neolithic Britain Some of the novel aspects of the Neolithic lifestyle were the keeping of livestock, the manufacture of pottery, the cultivation of wheat and barley and the manufacture of new types of foods for people and their domesticated animals. Grain cultivation and the knowledge of specific processing techniques spread from the Fertile Crescent across Europe, eventually reaching Britain around 4000 BC (Smith 1998). Barley and wheat were a brand new food resource to Mesolithic populations. The indications are that gathering, hunting and fishing continued to be important aspects of subsistence activity alongside this new practice of grain cultivation and processing. The keeping of livestock, such as goats, cattle and pigs, was an integral part of this new Neolithic culture. What were the animals fed on? Some potential food resources for the livestock would have been limited to specific seasons only. For example, branch and twig foddering of domesticated animals has been indicated by the analysis of goat and sheep faeces from Neolithic sites in Switzerland (Rasmussen 1993, Akaret & Rentzel 2001), but the twigs and branches with young, tender leaves would have been available only during spring and early summer. Grazing of grass would, obviously, have been another seasonal option. The practice of transhumance may have been a part of animal husbandry during the Neolithic in some parts of Europe and Britain (Waddington 1996, Akaret & Jacomet 1997). This, again, is a seasonal food resource. Spent grain or draff could have been available all year round. Older strains of barley, such as bere, provide about three times more draff than modern barley, making it an excellent source of animal feed for prehistoric cattle and pig farmers. Grains are generally considered to have been a source of carbohydrate during the Neolithic, being routinely ground into flour to make some kind of flat bread, gruel or porridge. However, with the right knowledge and using basic equipment that was available in the Neolithic it was easily possible for them to transform hard, inedible barley grain into malt, sweet mash and wort with spent grain or draff being a useful by product for animal consumption (see Dineley 2004). Barley lipids as evidence for mashing and sparging Grain products are ephemeral. They are consumed by people and animals. Charred grain from overkilned malt may remain in the archaeological record. So it is necessary to look at the surviving material culture – the buildings and the equipment - to assess whether the processing of grain to make malt, sweet mash or malt sugars was being practised in Britain during the Neolithic era. Such an analysis has been undertaken in some detail (Dineley 2004). Since then, I have continued this research and it does appear that the particular techniques of malting, mashing and sparging were known of and being practiced throughout Britain at this time. The evidence, however, depends upon an understanding of grain processing techniques as described here. 6 Merryn Dineley Spent Grain as Animal Feed in the Neolithic 2006, revised 2010 Even at sites where there is literary evidence for malting and/or brewing the archaeobotanical evidence is minimal. For example, we know the Vikings were making and drinking mead and ale – but where is the malt in the archaeological record? There are scientific techniques that could clarify barley processing methods in prehistory. Gas Chromatography/Mass Spectrometry (GC/MS) or High Performance Liquid Chromatography (HPLC) are analytical tools used to detect the presence of lipids or other substances within the fabric of ancient pottery. It can also be used to identify organic residues that are occasionally found on ancient pottery surfaces (Evershed et al 2001). Lipid analysis is a relatively new addition to the archaeologist’s analytical tools. Lipids are the fats, oils, waxes and resins that occur in all plants and animals. They are especially well preserved as absorbed organic residues in ancient ceramics. The structural diversity of lipids means that specific food types can be identified. It is a serious mistake to assume that, for example, pig fat in a pot means that pork was cooked within it. Fats can be used simply to seal pots, to make them waterproof. I have used fat sealed pots for mashing. Barley lipids, as mentioned earlier, have been identified in the fabric of Neolithic pottery from Barnhouse, Orkney, a village dated to c3500 BC (Jones 2002). A number of sherds of Grooved Ware pottery were analysed using the technique of GC/MS (Jones 1997) and several different food groups were identified. These included cattle milk and meat, unidentified plant material, bark resins, barley lipids and ‘unidentified sugars’ (Jones 2002:132,133). The latter two food groups are the ones that indicate the wet processing of barley using the specific techniques of mashing and sparging. This discovery of barley lipids and unidentified sugars raises the question of how they got into the fabric of the pottery. The sugars, being unidentified, are a difficult area to interpret and so further research is needed to determine whether they came from milk or from barley processing. The barley lipids, however, can only have come from the barley grain itself. Barley lipids are a waxy like seed fat component. They are present in the husk of the grain. They were interpreted by Andrew Jones as being evidence for the storage of dry barley within the largest of the Grooved Ware pottery vessels (ibid:132). It is not clear to me how the barley lipids could have migrated from the husk of the grain into the very fabric of the pots, simply by being stored in them as a dry product. However, given my understanding of grain processing techniques for malt sugars and ale, a much more likely explanation is that they were mobilised by hot water and that these large pots were being used for mashing the malt and/or sparging the barley mash (Dineley 2004). Barley lipids are only liberated in the latter stages of the sparging process, once most of the malt sugars and proteins have been washed out of the crushed barley mash by the hot water (personal communication from brewers). If a vessel was repeatedly used for this type of processing, then the lipids would transfer into the fabric of pottery. In my opinion, the presence of barley lipids in Grooved Ware pottery from Barnhouse is the clearest evidence so far that barley was being processed into sugars. Therefore spent grain would certainly have been available to people at Barnhouse, Orkney, and probably elsewhere in Britain, during the Neolithic to use as animal feed. 7 Merryn Dineley Spent Grain as Animal Feed in the Neolithic 2006, revised 2010 Since this paper was first published in 2006, evidence of caried pig teeth at Durrington Walls has been found. The idea that they were fed honey to ‘sweeten the meat’ has been suggested (see Time Team website). This is not how honey roast pork is made! The pigs were fed spent grain, a much more likely explanation. Summary and Conclusions Grain cultivation and the processing of wheat and barley into a variety of different foods and drinks was an important part of daily life during the Neolithic. Unprocessed grain is not digestible by humans or animals. It has to be processed in some way in order to make it edible. The easiest way to make grain tasty and nutritious is by malting it. Then it can be easily crushed, mashed and sparged to extract the malt sugars as a liquid product – the wort. This sweet malt liquid could have been consumed with milk, as a nutritious malted milk drink for people. Or, the sweet liquid could be fermented into an alcoholic drink - ale. Animals would have eaten the spent grain, the by product of this kind of barley processing, with as much relish as the people, adults and children alike, ate and drank the sweet malt products. The particular skills of the maltster and the brewer have been learned over the millennia. My research (2004) indicates that knowledge of malting dates back to the early Neolithic cultures of the Near East and Levant, around 10,000 years ago. The earliest chemical evidence for beer comes from pottery jars found at Godin Tepe, in the Zagros mountains of Iran and is dated to c4000 BC (Badler 2000). Calcium oxalate, a substance which precipitates out of a fermenting barley wort, was identified on the inner surface of the pots. Therefore the discovery and knowledge of the several stages of the transformation of grain into its various products developed between these two dates. Much more research is needed to unravel the complex mystery and the prehistory of malting and brewing. Grain was a most useful crop and it was processed to make a wide variety of products in the Neolithic. There are many possibilities, ranging from grinding the grain into flour to make flat bread to processing it by malting, mashing, sparging and fermenting. One of the benefits of brewer’s spent grain was that it would have been available all year round. Malt stores well, provided that it is kept completey dry, and it was available to be processed into malt sugars at any time of year. Grain would have provided food for people and their livestock. This research, as well as suggesting a previously unconsidered food resource for livestock in the Neolithic, has highlighted the many potential products of grain as well as the crafts and skills of the maltster and the brewer. Grain cultivation and processing was a fundamental part of the Neolithic cultural package. An appreciation and understanding of the necessary techniques and the possible products that can be made from grain illuminates our understanding of daily life in the Neolithic. The special and new techniques necessary to make food and drink from grain originated in the Near East and Levant. Much has been written about where, when and how grain domestication took place and there are many theories about the transition from hunting and gathering to an agricultural way of life and why people decided to deliberately cultivate this particular crop (see Smith 1998:207-214). These 8 Merryn Dineley Spent Grain as Animal Feed in the Neolithic 2006, revised 2010 explanations are wide ranging and include discussions of population growth, climate change, competitive feasting and social pressure. In my opinion, it is just as important to ask what was being made from the grain and what specific kind of processing was being undertaken by these first agriculturalists in the Fertile Crescent, Europe and Britain. Malting and mashing the grain for sugars have not been considered as possibilities for grain processing within a Neolithic context. The assumption that grain was used to make only flour, bread or perhaps some kind of ‘porridge’ or ‘gruel’ has neglected the crafts of malting and mashing and it also confuses oat-based products with those of the other grains. I hope that, in the future, further research will enable us to understand more fully the evolution of grain processing over the millennia and the important part that it has played in the development of farming and animal husbandry. Bibliography Akaret, O. & Jacomet, S., 1997 “Analysis of plant microfossils in goat and sheep faeces from the northern lake shore settlement of Horgen Scheller – an indicaton of prehistoric transhumance?” Vegetation History & Archaeobotany 6, 235-239 Akaret, O. and Rentzel, P., 2001 “Micromorphology and plant fossil analysis of cattle dung from the neolithic lake shore settlement of Arbon Bleiche 3” Geoarchaeology Vol 16, Issue 6, 687-700. Badler, V., 2000 “The dregs of civilisation: 5000 year old wine and beer residues from Godin Tepe, Iran” Canadian Society for Mesopotamian Studies Bulletin 35, 49-56 Bewley, J.D. & Black, M., 1994 Seeds: Physiology of development and germination Plenum Press Dineley, M. & Dineley, G. 2000 “Neolithic Ale: Barley as a source of sugars for fermentation” in Fairbairn, A. (ed) Plants in the Neolithic and Beyond Neolithic Studies Group Seminar Papers 5, 137-155, Oxbow Books. Dineley, M., 2004 Barley, Malt and Ale in the Neolithic BAR S1213 (British Archaeological Reports, International Series), John & Erica Hedges, Hadrian Books. Evershed, R. P., Dudd, S.N., Lockheart, M. J., Jim, S., 2001 “Lipids in Archaeology.” In Handbook of Archaeological Sciences. (eds. D.R Brothwell and A.M. Pollard) Chapter 28, 331-349, John Wiley & Son, Ltd. Hernandez, A. M.., Rodriguez, J. L., Lopez, B., Zerquera, O. L., 1999 “Chemical and functional characterisation of brewers’ spent grain.” Instituto de Investigaciones para la Industria Alimentaria, Havana, Cuba. Alimentaria (Madrid), 302, 105-107. Hough, J. S., 1985 The Biotechnology of Malting and Brewing, Cambridge Studies of Malting and Brewing, Cambridge University Press. Jones, A., 1997 A biography of ceramics: food and culture in late neolithic Orkney. Unpublished PhD thesis. Glasgow University, Glasgow. 9 Merryn Dineley Spent Grain as Animal Feed in the Neolithic 2006, revised 2010 Jones, A., 2002 Archaeological theory and scientific practice. Topics in contemporary archaeology, Cambridge University Press. Lewis, M. J. & Young, T. W., 1995 Brewing Chapman and Hall Patrick, A., 2002 “Malthouses in Northumberland” Archaeology in Northumberland, 2002 Edition Northumberland County Council pp11,12 Rasmussen, P., 1993 “Analysis of goat/sheep faeces from Egilzwil 3, Switzerland: evidence of branch and twig foddering of livestock in the neolithic” Journal of Archaeological Science 20, 479-502. Santos, M., Jiminez, J. J., Bartolome, B., Gomez-Cordoves, C., del Nozal, M. J., 2002 “Variability of brewers’ spent grain within a brewery.” Food Chemistry 80 (1), 17-21. Smith, B. D., 1998 The emergence of agriculture. Scientific American Library, W. H. Freeman and Company, New York.. Vietor, R. J. and Voragen, G.J., 1993 “Composition of non starch polysaccharides in wort and spent grain from brewing trials with malt from a good malting quality barley and a feed barley” Journal of the Institute of Brewing 99 (3), 243-8. Waddington, C., 1996 “Putting rock art to use: a model of early transhumance in north Northumberland.” Northern Archaeology (special edition) 13/14, 147-177. 10