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Lee Eales - Tasting the Past: Unearthing the Chemistry of Medieval Beer - Episode 19
171 Plays8 years ago
Archaeology and Ale proudly presents - Lee Eales, and his talk “Tasting the past: Unearthing the Chemistry of Medieval Beer”. This talk took place on Thursday 12th January upstairs at the Red Deer pub in Sheffield.
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Transcript
Origins of Archaeology and Ale Podcast
00:00:02
Speaker
You are listening to the Archaeology Podcast Network.
00:00:29
Speaker
Hello, welcome to this month's episode of Archaeology and Ale. The Archaeology and Ale podcast is a recording of a monthly series of talks presented by Archaeology in the City, part of the University of Sheffield Archaeology Department's outreach program. These talks are hosted upstairs at the Red Deer Pub in Sheffield on the last Thursday of the month during the academic year. But if you can't make it to Sheffield, don't worry, because you can listen here online thanks to the Archaeology Podcast Network.
00:00:56
Speaker
To find out more about archaeology and ale, including community events, upcoming talks and demonstrations or activities at your school or community group, look us up on Facebook, Twitter or WordPress. For more information about this month's presentation and the speaker, please check the show notes on the Archaeology Podcast Network Archaeology and Ale page.
Chemistry of Medieval Beer with Lee Els
00:01:27
Speaker
Why excuse? Whilst instruction's going on.
00:01:43
Speaker
But anyway, today we've got Lee Els giving us a talk on tasting the half and adding the chemistry of medieval beer. Lee at the moment is studying a PhD in environmental science as well as applying new organic chemistry technologies to archaeology. And with that, I'll let Lee take it away.
00:01:59
Speaker
Thank you. So thanks for coming, everybody. If you want to try them beers, trust you, dude. So there is a cherry beer, which don't contain any hops. There's one that's moderately hopped, and then there's one that's a modern American IPA that's stuffed full of hops. You just try and think about differences in flavor at three different beers. And then imagine what that tastes like in seven or 800 years.
00:02:29
Speaker
essentially what I'm trying to do is reconstruct them tastes now on medieval stuff. Obviously we don't have any samples so we had to look at a different way that we would do that and we decided on pottery. So we came up with this kind of crazy idea that we would fire a laser at pottery and see if we could reconstruct what beer was like.
00:02:58
Speaker
So we thought, OK then, if we're going to do it, let's take it seriously and do it properly. So we came up with some research aims, and that was to assess feasibility of identifying beer and ale in archaeological ceramics.
Reconstructing Medieval Beer Flavors
00:03:15
Speaker
And second one was, as a more of an archeological question, was when did they introduce hops in Britain? So if you look at all the written sources, it's really unclear when that happened. So before we had hops, we had this thing called Gruett that everybody used for bittering. So they didn't put hops in beer, they put a mixture of all these herbs. So like these here, lots of them.
00:03:44
Speaker
And like I said, documentary evidence, I know you can't see this, but it's really unclear. So there's a document in Westminster Abbey. I think it comes from, I think it's from a different Abbey. It's just been stored there. But that talks about hops and its 11th century in date. Then there's a book, this former Curie by Samuel Pegg.
00:04:10
Speaker
And this states that hops weren't introduced until after Henry VIII. So you've got sort of like 500 years there, where we're not sure whether we were using hops or not. So we decided on medieval period, and these are reasons that we did so. So you've got rise at monastic orders.
Technology in Beer Archaeology
00:04:34
Speaker
So monasteries became really, really powerful in this period, so much so that Henry VIII decided to get rid of them all because they were costing too much money. Monasteries are by far the biggest producers of beer in the country. So to give you an idea, at Durham prior, they're producing 1,200 litres a month.
00:04:56
Speaker
So to put that into context, based on sort of a cartillary when it says about issuing malt and stuff, you would need 27 hectares of barley to produce that much beer.
00:05:10
Speaker
That's per month. And if you think the estimate that it's one man, one beast, one day, one hectare, that's 27 days worth of ploughing to produce enough barley. So they're investing huge amounts of time and effort and labour. And final reason we chose the medieval period was monastery's extensive records, Grenada's records. They don't tell you
00:05:38
Speaker
specifics, what they do tell you is like how much grain malts they were issued, how much malted barley the brewer were issued. So then you can work out, try and get an idea about how much they're producing and stuff. So this is what I'm saying is my medieval period, what I'm going to study. It starts at Norman Conquest and ends at Reformation in 1536.
00:06:09
Speaker
So we thought we'd best come up with some research questions. If we're going to do this, I'm going to do it serious. So the first one was, is it possible to produce a fingerprint, a residue, and archaeological ceramics using mouldy MSI? So this is where laser firing comes in, where we fire a laser at a piece of pot. So this is what mouldy MSI is.
Mass Spectrometry in Historical Analysis
00:06:33
Speaker
So it's matrix-assisted laser desorption ionization mass spectrometry imaging. And initially, you need to prepare your sample in form of a thin section. Then you need to spray that sample with a matrix. This aids in ionization process. And what happens is you fire a laser at it. And if you imagine a cube of sugar,
00:07:03
Speaker
and you fire a laser at it and the energy generated from that laser makes that cube break up and you get the individual granules of sugar. Then what happens is it captures that in a gas
00:07:20
Speaker
It goes into this, which is the mass spec. And what it does cleverly is, while it's in the chamber, it records where it starts and it records where it finishes. And it measures time that it takes for that individual granule to get from A to B. And because you know energy that you've put into it from laser,
00:07:44
Speaker
You know, time a flight, what they call it, off. So you know, time it took for it to get from beginning at chamber to end at chamber. From that you can work out its molecular weight. Then from the molecular weight, it'll produce a spectra with hundreds and hundreds and hundreds of different molecular weights in it.
00:08:05
Speaker
Then you do your data mining whereby there are extensive databases online where you can look for individual compounds and their weight. They're not unique. There might be 20 compounds that contain the same molecular weight. But then you have to go and mine it even further and you look at where does that compound come from. So for example, if
00:08:33
Speaker
If there's 20 possibilities and 10 of them are from a sponge found in sea off California, you can be pretty sure that that's not gonna be involved in brewing, so you can eliminate them 10. And then it's like a process of elimination.
00:08:48
Speaker
And then you can produce an image, and I'll show you an example in a bit. And then finally, we do identification. That's where you think, OK, then, so this molecule is this. This is what I think it is. Then what you do is you buy that substance, and you put that fruit machine, and you record how it flies to see if it matches with your sample. If it matches with your sample, you know you've got an identification.
00:09:15
Speaker
So traditionally, in archaeology, we're looking at these proteins and lipids.
Experimental Archaeology: Brewing with Replicas
00:09:22
Speaker
And they generally couple that way GCMS. Advantage at MALDI is, because it's so much more sensitive, you can look at these smaller molecules. And these, if you take proteins, for an example, these will identify amino acids.
00:09:42
Speaker
So when you do solvent extraction and you run it through GC like we have done traditionally for the last 20 years, you possibly won't find a protein because it will have broken down into its individual amino acids. We can detect them amino acids. So if we're going to do it, we need
00:10:04
Speaker
We need to be able to prove that we can do it on pottery because pottery is a big giant organic piece of things and this machine won't discriminate what it ionises and what it didn't ionise. So I took assured replica medieval pot and as I said about amino acids I spiked it with arginine
00:10:29
Speaker
Then sprayed it with matrix, like I said earlier, that enables it to break up and capture ions so that they get taken into a chamber. And then I imaged it. And as you can see, we can detect it in ceramic. So we can discount all pottery that's ionized, and we can find amino acid.
00:10:51
Speaker
So then we thought, okay, now let's see how far we can take this. So on the bottom here, I don't know if people at might can see it. It's just a series dilution. So this is a 10-fold dilution of, I mean, of arginine comes out really bright. On the far left there, that's a million-fold dilution and we can still detect it in a piece of pot. So that just gives you an idea of how sensitive we can go with the machine.
00:11:21
Speaker
So we think you can fingerprint organic residues. Can that help us establish when hops were first introduced? Because after all, this is like an archaeological question that we're trying to answer. In order to do that,
00:11:41
Speaker
We need to be able to distinguish between hops, a hot beer and an un-hot beer. So like I said, they were using all sorts of different stuff. One of them is bogmirtle and hops. But if we can't, we need to be able to chemically see that when we put the samples through.
00:12:01
Speaker
So what I did is, much like these beers, what you've tried today, I went and bought two, one that contained ops, one that didn't contain ops. And this is a MALDI target plate. So this is traditional use, I suppose, of how you would introduce your samples to MALDI. I spotted them on a target plate, ionized sample, collected my mass spectra, and then I did this thing called
00:12:30
Speaker
principle component analysis and what that does is It reads it takes one sample and it says okay, so that constitutes that and it puts it in a in space and then it checks all other samples and it cross references against that one So if it's similar it will put it near it the further away is the more different it is and as you can see
00:12:57
Speaker
They separate art really nicely, the hopped beer and the un-hopped beer. We already knew that. It tells you on the label that they're different, you know? So then what we decided was we tried impotere. So I managed to get older some replica medieval serving jugs.
00:13:16
Speaker
and I bought five bottles of a hot beer, five bottles of a un-hot beer, and poured one in, left it for 24 hours, and then refreshed it, and did that over five days. Then I thought, okay, then we need to smash them up and try them. Don't want to just smash them up on lab floor. Evo would not be happy if I did that. So we went to Bishop's house, and it just happens to have a 14th century floor.
00:13:44
Speaker
So we decided we'd smash them on that. Then I was talking to my friend, you know, and she says, well, really, you need a medieval wench if you're going to do that. So my friend dressed up as a medieval wench. And like a good wench, she was really clumsy and she dropped them and they smashed on floor. So I collected these up, the individual pots, obviously keeping them separate and thin sectioned them.
Medieval Brewing Herbs vs. Hops
00:14:12
Speaker
And then I ran it through Maldi again, and as you can see, we still get that, we did principle component analysis, we still get that separation, even in pottery, so we can discount whatever organics are in the ceramic and just focus in on the actual organics that we want to focus in on, which are beer in this case.
00:14:34
Speaker
So then what I did were I produced column plots. And what these do is they compare two samples. So in our case, it's a hot beer and a non-hot beer. And in Centoria, all these masses, all these mass-to-charge ratios, actually, are the most similar. So of the two samples and then the two extremes, it puts the most different masses
00:15:04
Speaker
out there into these bins. These are 0.2 bins. So they could be 20 different, 20 unique masses in there. So you could have 20 different compounds. And what you have to do then is you go back to your data mining, you go in, you look at each individual one, you discount the obvious ones that it can't be. And then what you're looking for is compounds associated with brewing that you can say, okay, that could constitute our fingerprint.
00:15:33
Speaker
And what we found in Opt1 was we found two compounds associated with hops. So these were the most different compounds. What we're hoping to do is take these compounds and build up, obviously not based on two, but build up 30 or 40 of these where you could say, with quite a lot of certainty, that's had a hop beer in it.
00:16:01
Speaker
You know, they're the key compounds from fermentation, from malting and from hops or whatever plants they're using instead of hops.
00:16:13
Speaker
You take them compounds, you can start then to say, this pot's had beer in it. Then you can look at it even further. Interesting thing about this one is we have this compound here, which is an alpha acid. This one's a beta acid. So this one's produced during boil. And this one is added after boil. So if I had to put my neck on line, I'd say that this beer would dry up and end.
00:16:41
Speaker
because you don't have any isomerisation of this, so you don't go through boil. So when it goes through boil, it changes compound. But because we've got this one, it means that they dry up to the end, which is, you know, it's an American IPA, they just stuff them in all the way through, don't they? So then we're looking at the Unopt beer, and we find this one.
00:17:06
Speaker
which is associated with coriander seeds. Now, on label at beer, it said coriander. It didn't say anything about seeds. So I emailed company and just politely asked them. And they said, yeah, we don't use leaf. We use seeds. So we can detect whether or not they're using seeds or leaves. So when we're looking at as medieval stuff, at the plants that they're growing, we'll be able to tell whether it's seeds, leaf, that they're adding instead of hops.
00:17:37
Speaker
So we think that if you get enough good samples, you will be able to start to begin to get a picture of how it's happening. Do you want to get that? I'm going to have a drink. Do you notice that I don't drink any of that feeling of you drinking as well?
00:18:11
Speaker
Also, where were I holding them? Right, yeah, so we can produce a chemical fingerprint and we can apply that to medieval pottery, providing we can get right sample size, which I'll come on to. So, next thing is, if they weren't using hops, if we're going to say, OK, it's not enough just to say, oh, yeah, that's had beer in it, but it weren't hopped. We want to know what they were using instead of hops.
00:18:39
Speaker
So like I said earlier, there's a big list from this book, actually. And other things get mentioned in courtilleries from individual monasteries. But basically, the pretty common plants that everybody, only one that I've had trouble getting old of is bogmirtle. Because it's a wild planet, it grows up more as you're not allowed to go and get it.
00:19:04
Speaker
But others, you can buy them. And if you go on Royal Society website, they'll tell you what closest relative is to medieval one that's available. So at the moment, I'm planting these up, a big variety of them. And what I'm going to do is I'm going to grow them.
00:19:26
Speaker
And I'm going to take samples at various stages.
Challenges in Archaeological Beer Research
00:19:31
Speaker
I'm going to let some flour. I'm going to take them. I'm going to take samples and dry them out, because in literature, it does say that they are taking samples and drying them out. And see how that affects chemistry when it's added to beer. And also, flowers, because I reckon these were growing wild in the garden. Some of them would have ended up flowering, and they were using everything. So that would have gone in beer.
00:19:57
Speaker
So then, in order to bring it all together, my plan is to take all historical records that we have and examine them. Big problem with monasteries, as I'm sure you know, is they were excavated years and years ago and you can't, you can't, with any confidence, trust where potters come from, how it's been stored, how it's been processed.
00:20:27
Speaker
because you need samples from really well excavated sites, from really robust contexts. You need a really good provenance, otherwise you're just firing lizards at stuff and it's not telling you anything archaeologically about what you are doing. And then you can faint section and you can, you know, and this comes with its own problems in the
00:20:52
Speaker
No matter how good all this lot is, if you get this bit wrong, your sample's no good. Vice versa, if all this is good and this is not good, your sample's no good. And if all these are good and these have been stored wrong or they've been scrubbed up, something silly, it's no good. So you need to bring all these things together so that you can get it onto a machine, having confidence that what you're seeing is real and you haven't generated it or it hasn't been generated by
00:21:21
Speaker
misuse or bad excavation or whatever. And then you can get your things, sorry, you can get your spectra and then from that, having already, knowing what you're looking for, rather than going in blind, you know, when you put a piece of pot on it, throws off about 14,000 data points of that 14,000, probably eight from actual ceramic.
00:21:49
Speaker
So if you just go in and go, oh, that might be one, you won't see wood for trees. Because like I said, ceramic is full of organics. You come up with this fingerprint, you're targeting what you're looking for.
00:22:03
Speaker
being really specific and it allows you, like I said with different compounds being associated with different aspects of brewing, you can sort of narrow it down and keep narrowing it down until you can say with some confidence this is a pot that's had beer in it and then you can start to say it's had a hot beer in it or it's had an un-hot beer in it. So that's about it really, thank you for listening.
00:22:41
Speaker
Come on, Roger. Well, I'm in touch with Historic England at the moment. Actually, I've had an email from Guy today, who's the ed scientific one, who's put me in touch with all ed scientists and post-excavation people of various units. So I'm hoping that I'm going to get relatively modernly excavated material from units.
00:23:12
Speaker
Obviously that's in an ideal world. We don't live in ideal world. It could be I'm expecting it to be tough And I'm also expecting it to be
00:23:22
Speaker
really random. So ideally, I'd like 50 samples of Yorkshire. But that's just not going to happen. It's going to be a case of they've got material. We know it's robust enough. I'll use that. And it could be anywhere in country. Wherever it is, I'll use it and then try and come up with some sort of geographical data to see if we can say,
00:23:44
Speaker
I don't know, it were regional, it were time-based or whatever when they swapped over. Because it says, I mean, old literature points towards them swapping to hops because it increased its shelf life a bit.
00:24:00
Speaker
But modern science has looked extensively at hops. And I can't find anything that says it increases its shelf life. It just changes taste.
Tasting Medieval Beer: Sweetness and Differences
00:24:11
Speaker
And it's believed to be antioxidant. But it doesn't necessarily... I mean, it may do. I just haven't found it yet. But everything I've looked at so far would indicate that it doesn't.
00:24:23
Speaker
So there may have been other factors as to why they changed from great to hops. Could be possibly trade. If a particular monastery were on a better trade network, they had easier access and cheaper access to hops than maybe they'd changed. But honestly, at this stage, I don't know.
00:24:53
Speaker
I'm trying. I'm trying. But I mean, I know, surprisingly enough, I know a few brewers. And I can lay my hands on plenty of hops. Do you think medieval beer is nice, then? Honestly, no, it's not going to be... It's not going to be... It's going to be a completely different taste to what we associate with beer today.
00:25:17
Speaker
It's actually a lot sweeter. I've tried it in Mary Arden's farm where they brewed their own medieval ale. It's a lot sweeter than modern varieties, but it's quite nice depending on whether that's your sort of thing or not. We'll see. I don't like any of it. Medieval or modern. I quite like the medieval version, but they're quite like sweeter. Is that because they're adding only to it, to sweeten it?
00:25:42
Speaker
Not necessarily the period we were looking at that was like, Elizabeth the first time, honey was quite expensive. So they didn't necessarily use as much of it, they just didn't have any hops to it. Right, okay. Presumably because hops were expensive or? It just didn't seem to grow. Hops in Britain that much, compared to say, Germany. Yeah. So, if you're talking more about the first, it might be the introduction of sugar.
00:26:08
Speaker
Sugar was expensive in that period as well, so not necessarily. If you're wealthy, maybe. You do get a lot of sugar out of malts as well. So if you're not introducing hops, then you might be getting the sweetness from the malts and not being overridden by our prices and bitterness in getting that.
Closing Remarks and Future Talks
00:26:25
Speaker
Yeah, that will probably be it. It's sugar from the hop. Yeah. Are there any more questions still?
00:26:35
Speaker
Yeah. Will you be dressing up as a monk to do something? Erm... I will be doing some brewing. Er, maybe. I'm not adverse to idea. Quite possibly. But you can't... You're not allowed to come because you're going to come in your room and get up. It's totally not in keeping with time.
00:27:05
Speaker
Yeah, I am here. So thank you very much for the talk, Lee. No problem. And just so people know, next month's talk, we've got it from Chris Atkinson, who's actually here. It's an excellent talk. And it's on Roman Cred in the Hill, a community investigation. So once again, thank you very much, actually, for your help. Thank you. All right.
00:27:39
Speaker
you
00:27:49
Speaker
The show is produced by Chris Webster and Tristan Boyle and was edited by Chris Webster. This has been a presentation of the Archaeology Podcast Network. Visit us on the web for show notes and other podcasts at www.archaeologypodcastnetwork.com Contact us at chrisatarchaeologypodcastnetwork.com