Saturday, 24 September 2016

a morning with maltsters, part three: on the tour, some archaeological thoughts

We left the meeting room of the Highland Park Distillery and started our tour of the maltings. I'd forgotten my camera, however it gave me the opportunity to make notes and think a bit about the archaeological evidence for making malt.

This was not my first tour of a malting facility. Years ago, when I started my post graduate research into the archaeology of malt, ale and beer I contacted Thomas Fawcett and Sons, Maltsters, in Castleford, West Yorkshire and asked if they could show us round. They were very helpful and friendly. Soon we had been given a personally guided tour of the maltings by James Fawcett himself. Fawcett's make malt for the brewing industry using traditional floor malting techniques as well as having modern Germinating Kilning Vessels. There's a short film on their website where the ancient craft of floor malting can be seen. We'd wanted to see how an industrial maltings worked, having already visited an 18th Century grain barn at the Corrigall Farm Museum, Orkney, with a threshing floor, malting floor and grain drying kiln. Making malt is the same process, whether you are in a grain barn on a farm or at an industrial floor malting. The only difference is the scale of the task.

The tour of the Highland Park Maltings began with the steep tanks. Barley is steeped in water with regular air rests. Air is bubbled through. Steep tanks vary in size, obviously, but the basic principle is to get the barley wet enough and aerated sufficiently to trigger the germination process.
the steep tank, barley in bubbling water, with regular air rests
source MAGB

Steep tanks emulate a traditional and probably ancient technique. Maltsters in history and prehistory would have put their harvested grain into a porous bag and then left it in a shallow bubbling stream for a few days. This practice would, of course, leave absolutely no archaeological evidence. I was first told about it by an Orcadian farmer, maltster, brewer and crofter, Harry Flett, who was the custodian of the Corrigall Farm Museum.

a babbling brook, plenty of water and oxygen here
source wikipedia images
In Britain, people began to grow barley and wheat around six thousand years ago. This was the neolithic era, when hunter gatherers settled down and grew crops. What were they doing with the grain? How were they processing it? The consensus of opinion in academic archaeological literature and belief is that, since the earliest neolithic, they were grinding it into flour to make bread. Perhaps they were boiling it up to make porridge or gruel. The possibility of making malt has not been taken seriously. Many archaeologists, including professors, have shouted at me when I've made this suggestion at conferences. They don't like the idea of making malt in the neolithic.

I've written about some aspects of my research into neolithic grain processing, grain barns and the "first farmers" in an earlier blog. Many of the neolithic rectangular timber buildings in Britain and Ireland were situated beside or close to streams and rivers. Carbonised barley grains with missing embryos have been discovered at a number of these ancient sites. I think that they are good candidates for grain barns and malt houses five thousand years ago.

The steeped grain is transferred to the malting, or germination, floor. This is where it begins to grow visibly. Conditions have to be right. It's too hot in the summer months for floor malting, however, with the modern GKV systems it's now possible to make malt every day of the year. At an industrial floor maltings there are large amounts of grain to be carefully transferred from one place to another. We were introduced to the malt chariot.

steeped grain goes into the chariot
source here
from steep tank to malting floor
source here

According to Distillery Manager Marie Stanton, a malt chariot is a tricky thing to learn how to drive. The maltsters are experts at it, of course. An industrial floor maltings has to deal with large amounts of malt which is couched, then spread out on the floor. The chariot at Highland Park was in use regularly for this purpose. Ambient temperature and weather conditions dictate the depth of the grain bed.

There were several wooden malt shovels, or shiels, leaning up against the wall. They are used to turn the malt. It's a long job and in an industrial maltings like this, team work is crucial. It takes hard work and skill to turn tons of malt on the floor using one of these. On the tour we were told that some maltsters at the Highland Park were ambidextrous, able to turn malt to the right and to the left with ease. Others preferred to just work one way, which seems to be how the owner of this well worn malt shovel worked.

A 19th Century malt shovel, well worn from use
source here

As well as wooden malt shovels, fish tail rakes are used. These make the job so much easier, follow the link below the photo to find out why. Raking the malt is not just a skill, it's an art.

A medieval style custom made malt rake, with fish tails, used by Riverbend Malt House
How did neolithic and bronze age maltsters turn their malt? What did they use? They had no metal rakes. Wooden tools rarely survive in the archaeological record. I've sometimes thought that an animal's shoulder blade might have been a suitable tool. A scapula is a sturdy thing, it has the shape of a shovel and could be used for many tasks that the "first farmers" needed to do. It would do the job of turning the malt nicely. Has anything been found that might support this idea? There's only one discovery that I know of. During road works in 1987 at Achavanich in Scotland, a female cist burial dated to the Bronze Age was discovered. It had contained the crouched burial of a young woman, however only the skull and a few bones remained.

The grave goods that accompanied this young woman were these: a beaker or food vessel, a thumb nail scraper, two flint flakes and, unusually, the shoulder blade of an ox. The beaker or food vessel had organic residues within it. This is another rare find. According to the official site records (HER)

"The contents of the beaker were analysed by Dr Brian Moffat of SHARP who, from a preliminary examination, suggested that it contained: prepared cereal grain, honey, added flowers and fruit (including meadowsweet, bramble & wood sage), and the sap of birch and alder trees."
 
Similar residues have been found in other bronze age pots and have been identified as the remains of ale. These two things combined, the pot with cereal based residues and an ox shoulder blade, suggest to me that the woman may have been a maker of malt and ale. She had been buried with the necessary equipment. I mentioned this to a couple of people on the tour and they agreed it could be a possibility. The young woman who was buried 3700 years ago is now the subject of a new investigation by archaeologist Dr Maya Hoole. The details are here if you are interested.

ox shoulder blade from the Achavanich burial, was it used to turn the malt?
source here (this is a screen grab from the Facebook page)
The next part of the tour took us to a small room, the laboratory, where the viability of grain for germination was assessed. Why does it need to be tested before it is steeped and turned out on the malting floor? Because barley has a latent dormancy after harvest. It must be stored, in a dry place, for a few weeks or months before it will germinate. The reasons for this and the biochemistry behind it are not yet fully understood. The length of dormancy can vary between crops and barley variety. Traditionally, grain has always been left for a while after harvest. People have known about latent dormancy for a long time.

Grain that will not germinate is useless to a maltster. Upon delivery, samples are taken from every batch of grain. Individual grains are selected at random and tested for viability. This can be done by steeping them in a solution of hydrogen peroxide at 0.75% at 18-21 degrees Centigrade. Germinated corns (seeds) are counted after three days. For a working maltings, this takes too long.

A quicker method of checking viability is to cut a grain longitudinally and use tetrazolium chloride which stains the embryo pink. The maltster can get a result in half an hour. There was a very nice little grain cutting machine in the laboratory at Highland Park, used to cut grains in half for testing from every batch of barley. Shame I forgot my camera, but here's a picture of a stained living barley grain from the MAGB website. Pink toed barley, that's what the maltsters call it, if the barley has a pink toe then it's good for making malt.
white endosperm, pink embryo, it's alive!
source here



The final part of the tour was to climb the old narrow wooden staircase, it was more like a boxed in ladder, to look at the kilning floors in the loft. We were treading in the footsteps of maltsters past, it was a strange feeling. The steps were worn, malt has been dried here, in the same way, for two hundred years. We looked through the window to see the green malt, steaming as it began to dry. It looked very much like the photo below. Drying malt on this scale takes three or four days. The maltsters turn it at regular intervals so that it dries evenly. Hot air and peat smoke from the fire downstairs passes along the flue and through the bed of wet malt, imparting flavour, drying it gently so that the malt is not killed.

green malt at Highland Park, steaming on the kiln floor as it slowly dries
source: a blog by the whiskyspeller's here
We left the kilning floors by a small door which led us onto a metal walkway on the roof, right beside the distinctive pagodas. Whenever the malt is being dried there is steam coming from the pagodas. We had great view over Kirkwall and a new perspective of the Distillery, a place that we often drive past. 

the twin pagodas of the Highland Park Distillery
source here
Finally, we went down the metal staircase on the outside of the building to see the kiln fire downstairs. The maltsters start the fire with coke to warm the kiln, after this, peat from Hobbister is used. The peaty smoke flavours the wet malt. Coke is used at the end to thoroughly dry the malt. Each fire needs to be run slightly differently, depending upon the batch of malt. It's just another of those maltster's skills that can only be learned by experience and practice.

the kiln fire, it's a long way from the malt and there's a metal flue
This kiln has a fierce fire but is situated a long way from the malt. In a pot kiln, you need great heat to fire the pots. The principle with a grain or malt drying kiln is completely different. Hot air and smoke pass along the flue and through the bed of green malt. There are sturdy metal linings to contain the sparks and make it safe. I don't want to go into any more whisky making details. My interest is in making malt for brewing ale and beer. 

Today there are many different kinds of malt being made by maltsters for brewers. It can be confusing for a non brewer. The most crucial is the base malt, the one that is made and dried like this, carefully and slowly to keep the starch converting enzymes alive. These enzymes are needed in the mash tun. Base malt provides all the necessary sugars for fermentation. Other malts, such as crystal malt or chocolate malt have only been made since the mid 18th Century. Just to confuse the issue even further, there is also roasted barley, which is not malted at all and which gives dark beers like Guinness and porter their distinctive black colour and flavour. Hops add bitterness and other flavours, they are also antimicrobial. Unroasted barley alone cannot be used to make beer, it is added to the base malt. Unroasted barley has no enzymes.

Specialist malts provide colour and flavour to the finished ale or beer. They are a modern thing; making roasted malt is not a prehistoric technology. Specialist malts are roasted at high temperatures that kill all the enzymes, therefore it is not possible to make beer using only this kind of malt. I shall have to write something later about this, it's a huge subject. 

Malt is a mysterious thing to most people. In the world of archaeological and anthropological literature I find few references to malt. There is very little meaningful discussion of it.  Assumptions have been made that malt is "toasted roasted barley sprouts". Another belief is that the archaeologist has to actually find "sprouted barley" with roots and shoot still intact for there to have been malting and brewing at their site. I have been told this many times by archaeobotanists. The reality is that the malt loses its' roots and shoots in the kiln. An archaeologist will not find them. There are many other indications that grain has been malted.

When you read the academic archaeological and anthropological literature about "alcohol production in prehistory", there is a belief, an assumption, that all you have to do is mush up a few sweet things, like berries, honey, some sort of sweet plant, maybe a bit of barley and some birch sap. Leave it in a bucket or a pot and, magically, you will have "some sort of alcohol". Making ale and beer is not like that at all. Malt is the essential ingredient. It provides both flavour and, more importantly, the necessary fermentable sugars without which there will be no ale. No beer. 

That's more than enough for now. I shall continue working on my post about alcohol production and some of the myths that surround it in the archaeological and anthropological literature. I look forward to comments and discussion with about malt in the future. Malt matters.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Here's a bit more that I've written about malt, malting, the history and the archaeology. I shall get around to tagging the blogs soon so they are easier to navigate.

Brewer & Distiller International February 2016
The craft of the maltster  
Food & Drink in Archaeology 4 eds Howard, Bedigan, Jervis & Sykes
grain dryers, malt kilns and malting ovens




Friday, 16 September 2016

a morning with maltsters, part two

Making malt involves a huge amount of knowledge, skill and experience. This is the second part of my write up of an Orkney Science Festival event that I was fortunate to attend. Making Malt took place on the morning of 7th September at the Highland Park Distillery, Kirkwall. If you haven't read part one, see here.

There were twelve tickets available. Malt, malting and the history of the craft is something that I'm particularly interested in, so I bought two tickets on the first day that they were available. Well worth it. The second presentation of the morning, by Distillery Manager Marie Stanton, was about the practice and techniques of floor malting. She gave us a fascinating insight into the craft.

To make good malt, she said, you need good quality barley as well as common sense, experience, commitment and an unnatural obsession with the weather. The first four things seem obvious but, the weather? What's that got to do with making malt? Malt is a living thing, it requires careful handling and processing. The maltster needs to be very much aware of the weather, looking after the barley on the floor as it begins to germinate and adjusting things accordingly. In cold weather, the barley is couched, or heaped up deeper on the floor. In warm weather, such as the day the seminar was held, they had been raking it out thinner, to cool it. The grain generates heat as it germinates on the floor.

This is the ancient craft of floor malting, a craft that has been around for thousands of years. Decisions about length of steep, depth of bed and readiness for the kiln are based upon years of experience, knowledge and skill.

The steep is about more than just getting the barley wet before it goes onto the germination floor. Water temperature is important, as well as several air rests. Grain left in water will drown and be no good for germination. The idea is to rehydrate the harvested and stored grain up to about 45% moisture.

When sufficiently steeped, the grain is couched, spread, turned and raked regularly according to temperature and conditions. It begins to germinate. This might sound straightforward, but there's more to it than you might think. I'll write about this in the next blog, the tour of the Maltings. When we were visiting, malt was drying in the kiln but there was none on the floors.

steeped grain on the malting floors at the Highland Park Distillery, Kirkwall, Orkney
source: undiscovered Scotland where there is more about floor maltings

The presentation on Making Malt continued. Bowls of barley were passed round.

One contained freshly steeped barley. It had the aroma of wet grain, as you might expect. Another contained barley that had been on the floor and had begun to germinate. This had a pleasant, fresh, almost floral aroma which is hard to describe. The two bowls had very different aromas, although they were just a couple of days' processing apart. This was something I did not expect, these aromas of germinating barley.

There is some complex chemistry going on inside the grain as it begins to germinate. If you want to know more about the biochemistry and physiology of grain germination, there's a reading list at the end of the blog.

The purpose of germination is to allow the embryo to grow, just a little. Enzymes develop and begin to degrade the beta glutens, proteins and cell walls. This is known as modification. When the grain (green malt) is sufficiently modified, it's ready for the kiln.

The malt is dried slowly and gently, to preserve the enzymes. They will be needed in the mash tun. Although there is a fierce fire, the malt is not put directly above it. Hot air and smoke from the fire needs to pass along the flue and through the bed of malted grain, drying it gently over several days. The malt steams as it dries. Both peat and coke are used as fuel. The wet malt takes on flavour from the peat smoke. It's turned regularly in the kiln, to ensure an even drying process. The maltster does not want the malt to be too dry, does not want roots, but they do want plenty of enzymes. It's important to know your kiln, we were told. Each one is different and the drying of the green malt from the floor is a matter of great skill, experience and knowledge.

After kilning, the malt needs to rest for a few weeks before it is used. There was some discussion in the room about why this should be and why it affects the flavour. It seems that the complex chemical processes of this resting period are still not understood. There was general agreement that rested and unrested malt should not be mixed together. 

At the end of the presentation, a bowl of the finished malt was passed round. We were told that we could have a taste.

It was delicious, each malted grain imbued with a peaty, smoky aroma, very good indeed.

Next, the tour of the maltings. We saw bubbling steep tanks, malt chariots and shiels. We saw the malt, steaming in the kilns. As we went in I realised I'd forgotten my camera. I made notes, not just about what we saw on the tour, but also some thoughts on origins of this ancient craft and the potential archaeological evidence for it.

------------------------------------------------------------------------

After completing my Master's in 1999, I tried to get funding for a PhD looking into the history and prehistory of malting and the archaeological evidence for malt. I didn't get any funding, but I did get to spend several years preparing funding applications. I worked with brewing scientists and therefore I had access to their library at UMIST, Manchester, where I read up on malting and brewing science, grain germination physiology. I can't say that I understand it all but I learned a lot. 

Here are a few books that cover the subject in detail:


Bewley and Black 1994 Seeds: Physiology and Development
This is about all seeds, see the chapters on barley, barley germination, malting

Malts-and-Malting-Book-cover
Dennis Briggs 1998 Malts and Malting
This is what maltsters call “the bible”.





D E Briggs, R S Stevens, Tom Young, J S Hough 1981 Malting and Brewing Science: Malt and Sweet Wort, Vol 1, Springer US
There is a second volume on hopped wort and beer.




Saturday, 10 September 2016

a morning with maltsters, part one


The Orkney Science Festival is held annually. It's always a great week of varied and interesting events, talks, demonstrations and fun. This year there was a Malt and Malting seminar with a special tour of the Maltings at the Highland Park Distillery, Kirkwall. There were only a dozen places available and we were lucky to get tickets. We spent a fascinating morning with malting, brewing and distilling experts. It was all about the malt.

Making the malt for brewing and distilling is exactly the same process. The difference in processing techniques happens after the mash tun. A brewer takes the sweet liquid from the mash tun, calls it "wort" and adds hops or herbs, then ferments it into beer or ale. The distiller takes the sweet liquid, calls it "the wash" ferments it into alcohol and then distils it. The wort and the wash are two names for the same thing, the sweet liquid that is obtained from the mash tun. Every brewer who makes ale or beer from the grain knows what wort is because they work with it. People who have never made an ale or beer from the grain are perhaps a bit confused about what it is.
wort or wash?
Depends if you are a brewer or distiller.
source here
Dr Tim Dolan gave the first talk of the morning, explaining the fundamental aspects of what malt is, the biochemistry of malt, how it is made and a little of the history and development of the industry. His career in the malting and distilling industry goes back 40 years and he now teaches the subject. The other speakers were Marie Stanton, Distillery Manager of the Highland Park. She shared her knowledge of floor malting, then led us on a wonderful tour around the Maltings. The third speaker was Eric Walker, recently retired, a man with a distinguished background in all aspects of the malting, brewing and distilling industries. He talked to us about the prehistory and history of making malt and explained some technical details. They were quite a team and between them they had a huge amount of knowledge and experience of making malt.

"Malting is a process utilised by the Ancients to produce palatable alcoholic beverages: ale and beer"  (Eric Walker)

In previous years there have been talks about brewing and distillation, usually organised by the Institute of Brewing and Distilling. Tim told us that he thought it was about time there was a Science Festival event about malt, the Cinderella subject, because malt is the crucial ingredient for ale, beer and whisky. What is malt? It is grain that has been germinated under controlled conditions, then dried carefully in a kiln. Making malt has been a skill, an art and a craft for a very long time. Over the years I have given a few talks at the Science Festival. I was pleased that Tim remembered me and had been to my presentations on malting in prehistory, neolithic ale, grain barns and my most recent "Where were the Viking Brew Houses?" a couple of years ago.

The advent of the combine harvester in the 1940s transformed the grain harvest. The ancient and traditional way of harvesting grain by hand was extremely hard work, it was a time when the whole community worked together to bring the harvest home. On Orkney, where I live, grain was harvested by hand and stacked in stooks in the field until as recently as the 1950s. In case you don't know what a stook is, I looked online and found this painting by British artist Heywood Hardy (1843-1933). Painted in 1872, it depicts a typical scene of the time. I like the detail of the stook and you can see how they were made. The effort and hard work involved in making them can only be imagined.

 Corn Stooks by Bray Church by Heywood Hardy (1872) see here
This oil painting was done just a few years before Henry Stopes published his book about Malt and Malting, an Historical Scientific and Practical Treatise in 1885. It is now available to read online. Oxford University took the trouble to scan it in, many thanks to them for that. I first read it when I borrowed a copy from a brewing scientist when I began my research. It's such an important book and it is an excellent snapshot of the malting industry in the late 19th Century. Henry Stopes mentions the work of Louis Pasteur, who had recently published his work on Germ Theory which was to make such a huge impact on the brewing industry.

But I digress. Let's get back to the talk about malting.

Tim explained the biochemical processes of germination, with the embryo being the living part of the grain and the endosperm being the starchy food store. Malt, he said, is a living thing. It must be handled and processed carefully and correctly by the maltster. This was a point that was made several times throughout the morning. First, the harvested grain is steeped in water. It's crucial to allow air rests. The steep tank is drained of water at regular intervals. If the grain is left in water without air rests it will drown and this means that it will not begin to germinate.

Thanks to scientific research into grain germination physiology and biochemistry which began in the 1960s, we now know that when grain is  sufficiently wet and aerated, gibberellic acid is released from the embryo and the aleurone cells. This stimulates enzymes which convert the grain starch into sugars, the food source for the plant.

All grains can be malted. Barley is considered to be the best grain for malting but wheat, rye and oats can also be malted. Here's a useful diagram of the internal structure of a malted barley grain.

a malted barley grain more details here

The craft and skill of the maltster lies in getting the grain to start growing, but not too much. This is known as modification and there is some excellent and detailed information about what malt is and how malt is made on the Maltster's Association of Great Britain web site.

The Highland Park has three traditional malting floors where the grain is spread out after steeping. Raking and turning the malt is a crucial part of the process. We were told that this helps to maintain an even temperature and it also prevents rootlets from tangling. On the malting floor the barley begins to germinate. When the maltster sees the root and shoot being about four fifths the length of the grain, it is sufficiently modified and ready to be carefully and gently dried in the kiln. 

Modern techniques of making malt involve the use of Saladin boxes and drums. There are also huge germinating kilning vessels which can make three to five hundred tons of malt at a time. All year round. The quality of the malt can be controlled because it is easy to maintain precise temperatures and levels of moisture. The third speaker of the day, Eric Walker, gave an interesting talk about the industrialisation of malting and I'll write that up later. In the meantime, here's something I wrote about where the malting floors have gone.

Barley is self pollinating. Dr Tim Dolan emphasised this several times, but I wondered why was he making this point so many times? It was because it's so significant in understanding barley breeding. There were not so many varieties of barley in the past as there are today. The science and practice of cross breeding barley began at Warminster Maltings in 1904. This was news to me. Rather than tell you the story myself, here is the account from the Wiltshire Community History web page:

"The most famous name in local malting was that of Dr. Ernest Sloper Beaven, and his reputation is international. He was born in 1857 to a Heytesbury farming family, who moved to Boreham Farm at Warminster in 1868. Beaven said that he began to observe barley closely from 1878 and he became associated with Frank Morgan, Warminster’s leading Maltster. Beaven’s first experiments had been with onions and potatoes but from 1900 he was growing, selecting and crossing barley from seven initial different ‘races’. In 1904 he acquired fields on the Boreham Road for a nursery and in 1914 he launched ‘Beaven’s Plumage Archer’ strain of barley and continued with seed trials for the next 27 years. Beaven could claim that 85% of the total U.K. acreage of barley was grown from the progeny of just four plants, three of which had been selected in the nursery at Warminster between 1900 and 1904."

In the last one hundred years or so, much has been learned about barley and the biochemistry of germination, however, there is still much to be learned. Although some of the mystery and magic of malting has been studied and explained by scientists, some things about barley are little understood.

One of these is latent dormancy. Someone in the group asked about this and the answer was that it is still a bit of a mystery. There is a practical tradition of leaving the grain for a while between harvest and steep, because it will not germinate. This could be about variety, or it could be seasonal. The best thing I can suggest, if you are interested in finding out more about latent dormancy, is to search for the academic and scholarly papers on it. There are quite a few of them out there.

The next talk was about the skills, techniques and practicalities of floor malting and the turn of Marie Stanton, Distillery Manager, an experienced maltster at a number of distilleries. And then there was the tour of the Maltings.

There is only so much detail that one blog post can take, so I shall leave you with a picture of the maltsters hard at work at Highland Park Distillery. I forgot to take my camera to the seminar, but I did take plenty of notes, so I hope this will suffice while I get down to writing part two, while it is fresh in my memory.

maltsters, turning the malt at the Highland Park Distillery with shovels, or shiels.
source here







Sunday, 17 July 2016

big pots: fermentation and storage

Brewing ale in Neolithic Britain - it seems to be a controversial topic among some academic archaeologists. I'm not sure what the problem is with malting and brewing in the neolithic era. It could be that few people understand the processes involved in the transformation of grain into malt, wort and ale, so it is dismissed as a possibility.

The last few posts have been about explaining the saccharification in the mash tun, where crushed malt is converted by enzymes into malt sugars. I've also written a little about lautering, sparging and how to collect the wort.

We've been asked 'why not ferment in the trough. Why go to all the trouble of trying to collect a wort without bits in it?'

Firstly, alcoholic fermentation requires anaerobic conditions. A large vat (1000s of litres) within a building has a blanket of carbon dioxide over the fermenting beer, as in lambic brewing. A small trough (100s of litres) situated outside would have this blanket blown away. Secondly, during fermentation, the little bubbles of carbon dioxide produced by the yeast, stick to the smaller particles and lift them into the froth of the barm. You can see the towering barm in the picture below. It can turn into a really messy monster when it has a lot of little bits in it. After fermentation you would still have the problem of straining or filtering what brew has not been lost to the froth-over. That is a lot harder with little bubbles in it. A bed of husks will not form properly and filtering just doesn't work. 

Inoculating the wort: starting a fermentation
Once the brewer has obtained a quantity of wort by mashing, lautering and sparging, the next stage of the brewing process is the fermentation. Whether you mash in a large pot, a wooden tub with a spigot hole, in a trough in the ground or in a modern mash tun, the wort that you make must be dealt with promptly to prevent infection setting in. Wort does not keep well. Either you boil it, as is necessary with hops, and then cool and inoculate with yeast at the right temperature. Or you can inoculate a fresh wort when it has cooled, and then add the herbs. We found that meadowsweet flowers inhibited the yeast and are better added after the fermentation. To find out more about raw ale which, basically, is beer made from an unboiled wort, I suggest a look at this blog. Raw ale is a huge topic in itself.

fermentation in close up, this is the barm (foam) on a fermenting beer

There are a number of ways of adding the yeast to the wort to start the fermentation. Today, the brewer can add yeast directly, in dried form or as a yeast starter, when the wort temperature is just right. Many modern breweries keep their yeast starter in a fridge. They scoop some of the barm (foam) from the top of the fermenting beer and then store it in a cool place until required. The yeast culture can be kept and used for several months. 

Brewers in history and prehistory could also have used this simple and basic technique, keeping their barm/yeast culture in a cool place. In the 1980s, archaeologists found a medium sized grooved ware pot which had been sunk into the ground in the remains of one of the buildings at Barnhouse, Orkney. The pot, about a litre in volume, had been buried up to its' rim. Analysis revealed that it had contained some kind of 'cereal based mixture', but they were unsure about the pot's function. I think it may have been a barm pot. It was located in a large building, numbered eight by the excavation team and interpreted as a 'temple' or some other kind of ritual building. There were drains as well as many sherds of broken or smashed Grooved Ware pottery, representing pots of about one litre in volume. There was also evidence of feasting and what archaeologists refer to as 'ritual activity', although what that was is not made clear in the excavation report.

I would say that if an archaeologist is looking for a prehistoric ritual activity then the mysterious and magical transformation of grain into malt, wort and ale is well worth considering.

In Norway, Lithuania, Latvia and other places, the tradition of making farmhouse ale survives, with brewers passing on their skills, techniques and knowledge to their descendants. Old traditions of inoculating the wort are still practised in several areas of northern Europe. The picture below shows a wooden yeast ring or kveikering being used to inoculate a yeast starter.

wooden yeast ring or kveikering (photo from the beer blog of Lars Garshol)

Some sources say that the tradition of the kveikering dates back to the 18th century, although I wonder whether the concept might date even further back. It's difficult to be sure because, of course, a wooden object used to gather yeast and start a fermentation would not survive in the archaeological record. In the Viking era, apparently, a stick was used to stir the fermenting wort. This would put yeast onto the stick. Then, if it was kept dry, it could be used to start the next fermentation by stirring a fresh wort. In the Western Isles of Scotland there is a tradition of stirring the fermenting beer with a hazel stick (or wand) which is then hung up to dry and used to stir the next batch of wort, to begin the fermentation.

We did some experiments using a wooden spoon and found that this technique works perfectly.

harvesting barm from the fermentation vessel
barm/yeast drying on the wooden spoon (more photos here)

Big pots as fermentation and storage vessels.
The neolithic era was the time of the 'first farmers'. The earliest grain agriculturalists of the British Isles (c4000BC onwards) were also the megalith builders. They created magnificent stone circles and henges as gathering places for the community. They built stone tombs for their dead and they began to settle down. Associated with the 'first farmers' is the integrated 'cultural package' of grain cultivation, the management of domesticated animals (cows, sheep, goats and pigs) and the manufacture of ceramics. This was the 'neolithic revolution', a different lifestyle to the mesolithic hunter gatherers who had roamed the land for thousands of years previously. At this time in prehistory, the technology for making large stave built wooden vessels (vats, tubs, barrels) did not exist.

How did these neolithic 'first farmers' process their grain? Were they grinding it into flour, to make bread? Were they boiling it, making some kind of gruel or porridge? Or were they making ale from it, by malting, mashing, sparging and fermentation? For some reason, the possibility that such a thing as ale in the neolithic is considered to be a controversial idea by many archaeologists. I'm not sure why. 

Some of the large neolithic Grooved Ware pots might have been used as fermentation vessels. They are perfect in both shape and size. One particularly large Grooved Ware pot found at the neolithic village of Skara Brae, Orkney, was around 30 gallons in volume. Most of the large Grooved Ware pots were around eight to ten gallons. They are found at many ritual and feasting sites of the neolithic, in domestic contexts, for example at Skara Brae, Orkney, and at stone circles and henge monuments throughout the British Isles.

What is Grooved Ware? It is neolithic pottery that archaeologists have defined by its' decorative pattern of grooves and shapes on the exterior. Not all grooved ware has grooves; some of it has fancy applied decoration, with blobs of clay and raised patterns. Most Grooved Ware pots are bucket shaped, with a flat bottom. They are found throughout the British Isles, from Clacton to Orkney and Shetland and also in Ireland. Indeed, this style of pottery was first called 'Rinyo-Clacton Ware'. Rinyo being the name of a site on one of the Orkney islands, Rousay. It was a neolithic village larger than Skara Brae. Grooved Ware was also found on the south coast, at Lion Point near Clacton.

Here's one of Stuart Piggott's beautiful and classic drawings of British Neolithic pottery, showing what some of the Grooved Ware pots from the south coast probably looked like, based upon sherds found during excavations on the Essex coast, at Lion Point.

 

Pottery is frequently found during archaeological excavations. Archaeologists regard it as diagnostic. The discovery and identification of a sherd of pottery gives them a good clue about the date of the site. Neolithic and Bronze Age pottery was not glazed. It could have been waterproofed in several ways, by burnishing or by being sealed with fats, beeswax or milk.

a sherd of grooved ware
Pottery typologies are complex. It's an enormous area of archaeological study and I could not possibly go into every style and type of British Neolithic pottery in this blog. We would be here forever. There's Windmill Hill, Grimston-Lyles Hill Ware, Ronaldsway, Grooved Ware, Unstan Ware, Peterborough Ware, Ebbsfleet and so the list goes on. Most are round bottomed pots, with the exception of Grooved Ware. It took me many months to get to grips with these stylistic categorisations that have been imposed upon pottery of 5000 years ago.

Many bowl shaped pots are interpreted as 'cooking pots'. That seems fairly reasonable. What puzzles me is that whenever archaeologists find a very large pot, or the sherds of a large flat bottomed bucket shaped pot, it is almost always interpreted as a 'storage pot'. I have not yet come across a large pot from the British Neolithic that has been interpreted as a potential fermentation vessel, although some of them have a volume of several gallons and such large pots are often found at feasting sites, for example, at Durrington Walls, near Stonehenge.

If an earthenware pot is to be used to contain any liquid it must be waterproofed. We discovered, in our mashing and fermenting experiments, that beeswax worked very well as a sealant, as did butter and lard.

As a control experiment we tried fermenting mead in an untreated earthenware pot. The fermentation worked well, the room filled with the smell of mead, and the outside surface of the pot was covered in little beads of sticky sweetness. But the final product was disappointingly low in alcohol. It turns out that the alcohol diffuses through the porous pot much faster than the honey solution. This makes an untreated pot pretty useless for creating an alcoholic drink.

Here is a sample of some of the British Neolithic pottery types, as recorded by Stuart Piggott. You can see that there is a wide range of styles. Some have holes in the rim, to secure a covering or lid of, perhaps, leather. Some are deep, others are wide and shallow. I prefer to look at these pots with function in mind, rather than consider only their decoration and style.







Is there any archaeological evidence for the use of large pots for the fermentation or storage of barley wort? 
One of the very best indicators that a pot was used to ferment wort into ale, or for storing the ale, is the identification of beerstone on the internal surface. Beerstone precipitates out of a fermenting barley wort, it looks rather like eggshell. We have a lot of it accumulating on our plastic fermentation buckets and storage vessels.

It takes many hundreds of uses to accumulate a visible deposit of beerstone, but it is a certain proof of fermented wort. Brewers using plastic pipes in breweries often have to clean them of an accumulation of beerstone. It clogs the pipes.

Here is some beerstone from one of our fermentation vessels:



Beerstone has been identified on pots from a Bronze Age site in the Zagros mountains of modern day Iran. At excavations at Godin Tepe a great many pots and jars were discovered, they were stored in the University of Pennsylvania Museum. Subsequent analysis of a yellowish deposit on the internal surface of jars identified beerstone and it is generally accepted as unequivocal evidence for beer brewing. This pioneering paper by Badler, Michel and McGovern, published in 1993, tells the whole story and contains sufficient detail to be able to repeat the tests for beerstone on prehistoric pottery.

I wonder whether any archaeologists in the UK or Europe would consider looking for beerstone on big prehistoric pots? Maybe it is already being investigated. It would be great if this could happen, since this might end the apparent controversy about whether or not a big old pot was used for the fermentation of beer made from a barley wort.

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If you would like to make your own kveikering, here is some more information  and details of how to make one. Brewer Martin Warren of the Poppyland Brewery was so impressed by the idea that he made his own.

My conference paper from 1996 "Neolithic Ale: Barley as a source of sugars for fermentation" can be downloaded from my Academia page, here. 



Thursday, 7 July 2016

trough, mash and wort

How do you collect the wort when you have mashed in a trough in the ground?

The main problem, obviously, is that you can't lauter and sparge in the same way that you would if you had used a wooden tub as a mash tun with a spigot, or if you had a bespoke lautering and sparging vessel. When the trough is in the ground, it's a different story.

There are thousands of sites throughout the British Isles that archaeologists know as Burnt Mounds. All that remains is a large pile of fire cracked stones and the remains of a trough lined with either stone or wood. If you have never heard of burnt mounds before, I suggest you have a look at an earlier blog which explains what they are and some of the interpretations. Archaeologists agree that they were used to make water hot. This was achieved by heating rocks in a fire then putting them into the trough of water. What you do with that hot water is up to you. There are many possibilities. Some interpretations include bathing, others suggest cooking meat and some archaeologists think that they were used as a sauna. Another function is as a mash tun. With the discovery of chaff and grain in an oak trough excavated in Wales in 2008, a mash tun is a strong possibility.

Trough mashing at Bressay, Shetland

Replica trough at Bressay, Shetland, surrounded by fire cracked stones.
A few years ago, we mashed in a full sized replica stone trough, based on the one from the Bronze Age burnt mound site on the island of Bressay, Shetland.

The original trough and buildings were moved stone by stone, since it was in danger from coastal erosion.

A replica trough and hearth was built beside the Bressay Heritage Centre, for experimental archaeological work. It's been used to dye wool, it has been used as a bath and also as a mash tun by archaeologist Dr Lauren Doughton in her experimental work.

We were there in the summer of 2011 to mash some malt with her when she was working on her PhD about burnt mounds and troughs. 

The weather was rough, even though it was mid July. Buffeted by the wind and rain, we managed to run a mash and collect some of the wort. Our time was strictly limited because we had to catch the last ferry off the island and get back to our tent. A full set of pictures of the day's mashing, collection of wort and the final brew can be seen here on my Facebook page.

Brewers usually want to obtain as much wort as they can from the mash. There is potential for lots of waste from a trough mash unless you can find a way of maximising the wort extraction. The most obvious technique might be to let the grain settle to the bottom of the trough, then scoop the wort out using a jug or a bucket or something like that. It's tricky, as we discovered. Nevertheless, it works. Inevitably there will be bits of husk in the wort. This is not a problem. They will sink to the bottom again and it is easily possible to obtain a clear wort for fermentation from a trough mash.

Locally sourced clay was used to seal the corners of the replica trough before we began the mash.

Water was put into the trough. It became slightly murky, a grey colour from the clay luting that we had used to seal the trough. We were a bit worried, however, we did not need to be concerned because the resulting ale from this experiment was delicious, sparklingly clear and bright, perhaps the result of our accidental addition of clay to the water.

The hot rock rolling team, from the fire into the water.


The technique of rolling hot stones from the fire into the trough of water had been perfected by Lauren and her team in previous runs. Using garden forks and spades, the hot rocks were expertly rolled down the slope and into the water.

When the water reached strike temperature, 50 kilos of crushed pale malt was added to the 200 litres of water and stirred with a garden fork. You know when the water is the correct temperature for the strike, around 74 degrees Centigrade or thereabouts, because this is when you can clearly see your reflection in the water, no ripples, no steam. We double checked with a thermometer.

The strike:adding the crushed malt to hot water.

The saccharification takes about an hour and it's crucial to keep the mash temperature right for that time, adding hot rocks and stirring as necessary. We put a wooden board over the trough, to help keep the steam and the heat in. It was a good conversion of starches into sugars, a successful mash. The finished mash, when settled, was a deep dark brown and it tasted very sweet.

The finished and settled mash - the next job is to collect the wort and ferment it.
For non brewers, I should emphasise that wort is not alcoholic. Sugar ferments into alcohol, starch does not. The saccharification that happens during the mash is a crucial part of the beer brewing process. Fresh wort is very sweet and prone to all kinds of bacterial and fungal infections. On the three occasions when we have been too tired to process the mash after a demonstration, the next morning the mash was fizzy and sour. Wild yeasts and lactic bacteria infections had ruined it. It was useless. Wort must be collected as soon as it is cool enough to take the yeast. The yeast ferments sugars into alcohol. Herbs or hops preserve and flavour the ale or beer.

We were short of time and collected as much wort as was possible. The brewer used jugs, buckets and plastic containers to scoop from the trough. We had, of course, taken the stones out first, when they were cool enough to handle. The process of collecting the wort was hard work and we only managed to get about 6 gallons out of the trough before we had to pack up, load the van and catch the last ferry back to the Shetland mainland.

The brewer collects wort from the trough. The stones have been removed and are on the heap.

The wort was put into a fermentation vessel, yeast was added and the fermentation vessel was kept warm using sleeping bags as insulation. After about four or five days it had fermented into a fine, clear and strong ale. We used a handful of dried meadowsweet flowers as a preservative.

This is how we should have collected the wort
On the ferry back to mainland Shetland we realised that we had made a mistake. We should have piled the stones up in the trough to make a sort of dam, then we could have put the mash to one side and the wort would have been so much easier to collect. This is how the Moore Group archaeologists collected the wort at their trough mash demonstration at the Sixth World Archaeology Conference in Dublin, 2008.

They made a wooden trough and painted the bottom part with bitumen to ensure that it did not leak. They correctly assumed that the University authorities would not allow them to dig a big hole and set their trough in the ground.

Moore Group archaeologists filling the trough with water at WAC 6, Dublin
They heated the stones on a fire, dropped them into the water and added the crushed malt when the strike temperature was right. It was this hot rock mashing demonstration that inspired us to stop mashing in pottery vessels and start using troughs, wooden tubs and hot stones.

Here are some of my photos of the Moore Group's event:

1 heating the rocks
2 heating the water
3 saccharification: the mash









 
4 the stone dam, mash and wort separated

5 settled wort and mash

6 collecting the wort, it's cloudy because it has been stirred up.


Hot rock mashing is a spectacular process, the stones sizzle as they hit the water, the mash saccharification happens right before your eyes and the aroma from the mash smells delicious. This is a mysterious, magical transformation from grain starchiness into fermentable sweetness. Surely this would have been an event that would have amazed and impressed people in prehistory, just as much as it does in modern times.

Collecting the wort like this, by creating a dam of stones, is an extremely efficient way of doing it, perhaps even allowing for sparging. Once the first runnings have been collected from the trough, more hot water can be poured gently through the mash, thus releasing more wort for the brewer. There would be very little waste and a good quantity of wort could be collected.


Is there any archaeological evidence for the collection of wort like this?

It is rare that prehistoric troughs are excavated with the stones still within them. If you have excavated one like this, I would love to hear about it. Excavations in 2013 by Wessex Archaeology at Kingsmead Quarry, Horton, in Berkshire, England revealed the remains of four neolithic buildings. They were interpreted as having been 'houses', which is often the case with these discoveries. I do wonder how many of these neolithic 'houses' might have been used as barns or as buildings where the grain was stored and processed. But that's a story for another blog.

One of these four neolithic rectangular timber buildings at Horton caught our attention when we were looking at the pictures online. There appear to be some fire reddened rocks close by one of the buildings, in a heap. Here are the pictures that intrigued us, taken from Wessex Archaeology's web page, and the rocks can be seen in the picture on the left, in a pile at the bottom left hand corner of the building.

http://www.wessexarch.co.uk/system/files/imagecache/lightbox/wysiwyg_imageupload/4/2houses.jpg
Two neolithic buildings at Kingsmead Quarry, Horton, Wessex, full story and pictures here


They do look rather like modern bricks, but the stratigraphy indicates that they are contemporary with the building. So, are these stones an indication of hot rock water heating technology at neolithic Horton? Were they piled up in a wooden trough that has long rotted away? What were the people doing in and around this rectangular wooden building, over 5000 years ago?

I cannot answer these questions. I am nevertheless intrigued by this discovery. And so I finish this blog with a close up (thanks to Graham) of those mysterious fire reddened stones and welcome interpretations, comments and discussion.

a close up of those mysterious fire reddened stones beside the neolithic building at Horton

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If you want to know what our Bronze Age Trough Ale, with meadowsweet, tasted like, we sent some to Mr David Connolly of BAJR (British Archaeological Jobs & Resources). Although he struggled to open the parcel, he gave his opinion on the ale's flavour and strength. It is sometimes said that prehistoric ale was weak, cloudy and sour and that it tasted disgusting. We disagree.

Here is the link: https://www.youtube.com/watch?v=wpvPi25TTOI

Quinn, B., & Moore, D. 2009 ‘Fulacht fiadh’ and the beer experiment’ in Stanley et al (eds) Dining & Dwelling. NRA Monograph Series No. 6, 43-53, NRA, Dublin.