Today, we’re thrilled to introduce you to a man with what might be one of the most intriguing jobs in the brewing industry – yeast hunter Juan Ignacio Eizaguirre. Born in Buenos Aires, Argentina, with roots in the Basque Country, Juan has traveled the world in search of wild yeast, uncovering the secrets of fermentation. From the forests of Patagonia to ancient beer caves in Germany, he has dedicated his career to exploring the biological foundations of beer and pushing the boundaries of brewing science. Currently based in Bavaria at the world-renowned Weihenstephan, Juan is part scientist, part adventurer, and a true pioneer in discovering how yeast shapes the beers we love.

In this episode, Juan takes us on a journey through his work and passion – mapping yeast diversity, uncovering the mysteries of ancient strains like Saccharomyces eubayanus, and transforming his findings into innovations for brewers worldwide. He also shares his experiences in Argentina’s thriving craft beer scene, his adventures in South America, and what it’s really like to hunt for yeast in some of the most remote and historic locations on the planet. So grab your favorite beer and join us as we delve into the incredible stories, science, and spirit of the yeast hunter, Juan Ignacio Eizaguirre…

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Markus Raupach: Hello and welcome to another episode of our podcast, BierTalk. Today we have maybe the guy with the most interesting job in the world on the phone here. We’ll be talking to Juan Ignacio Eizaguirre. I hope I pronounced it right. He will correct me if I didn’t. It’s not an easy name. It’s a Basque name. But he’s also connected to Argentina, and also he’s in Germany, and he was in America and in Asia and in many caves and lost places around the world. So he is a yeast hunter. So, Juan, it’s great that you are here. Maybe you say some words about yourself, and then we start into the talk.

Juan Ignacio Eizaguirre: Okay, perfect. The last name was perfect, yes, so thanks, Markus for the invitation. It’s really glad to be here with you, talking about beer. This is most important stuff. I am from Argentina. As maybe, you know, in Argentina we have a mixture of different cultures. In my case, my last name came from the Basque Country. That’s why it’s like a Basque name. I was born in Buenos Aires. Then I studied biotechnology here in La Plata, and then I moved to the south to Patagonia. In Patagonia, I did my PhD on brewing yeast, mainly working with Saccharomyces eubayanus. Then we can talk more about that. And then, after the few years on PhD and working with that as yeast hunter, at some point, then I moved here, and I worked in Weihenstephan with Matthias Hutzler and Martin Zarnkow, looking for yeast but now in other environments.

Markus Raupach: Yes, what a fantastic story. So we already had a podcast with Martin and Matthias in the German version of the BierTalk. So I’m very happy that we now do the English one and also tell our English-speaking audience about your fantastic job. Maybe first of all, do you have a favourite beer or other words, what beer would you drink maybe tonight?

Juan Ignacio Eizaguirre: Ah, well, that’s an interesting thing. If you’d asked me a few years ago, I would say like, maybe an American Pale Ale, some Pale Ale, something like that. I can drink a lot. But here now I’m living in Freising in Bavaria, I for sure I will drink Weiss beer tonight.

Markus Raupach: Yes, of course. At the end, they all come back to the Bavarian classics. To be honest, Argentina has a great beer community and a great craft beer scene. And I have a lot of friends there, which I normally meet when I do beer judging around the world. And I’ve had great beers from there. So when you were still in Argentina, did you have some contacts to the craft beer world there?

Juan Ignacio Eizaguirre: Yes, sure. So I set in as a home brewer in 2011 and most of the friends that I met in that time, they are brewers now in Argentina, in really big breweries there now. So always, I always had contact with them. And in my former lab in Bariloche, we work really close together with the brewers, with the breweries, not only in Patagonia but also in the rest of Argentina. And I’m also a beer judge. So I used to do the same in Argentina.

Markus Raupach: Just having some beers and talk about them.

Juan Ignacio Eizaguirre: And visit different places in Argentina, South America, and have nice relations with brewers all around South America and drinking beer for sure.

Markus Raupach: Yes, yes, I was in Chile several times for judging there, and I would definitely come back this year for new competitions, the Copa Araucania.

Juan Ignacio Eizaguirre:  Ah, great.

Markus Raupach: I’m looking forward to that.

Juan Ignacio Eizaguirre: So have you ever been in the in the South of Chile, or always in Santiago?

Markus Raupach: No, I only have been to Santiago and to Valparaíso and Vina del Mar and this, but not south so I’m very much looking forward to that.

Juan Ignacio Eizaguirre: Perfect. So if you have time, you cross the Cervecera and also visit some brewers in Bariloche.

Markus Raupach: Okay, I will come back to them, definitely. Yes, it’s a fantastic beer and also South America is a great continent to visit, and there’s so many breweries and such. A big emotional beer world with a lot of different beers, and very great also local fruits, local herbs, local spices, local wood and local yeast, maybe also. So there’s a lot of things going around, but maybe in general, was beer always something like a dream when you grew up as a boy, or was it occasionally that you came to that?

Juan Ignacio Eizaguirre: So you know that? Yes, I’m from Argentina, and Argentina is more a wine country. And when I started at the university, all my friends, my colleague there, always laughing on me, because I always said to the professor there when they ask, why are you studying biotech? And all of my friends that wanted to get a cure for cancer or HIV or whatever, so do something with health, and I always got the same answer, like, no, I wanted to know how to produce wine, but in a scientific way. And the bad thing with the wine is that you can only ferment it once a year because you need the harvest of the grape. And at some point, I have this, one of the courses that I did there, the professor said, okay, we are going to make one of the oldest biotechnologies products in the world, beer. So he teach us at the university how to brew beer. And since that moment, I like get in love of that. So I moved from the wine to the beer, and then, yes, I started to make beer in my home, then with my friends and then at some point, I moved to this, to Patagonia, to do this PhD on the brewing science. And then I get more into the breweries. When I finish, I started to make a consulting in Argentina, also in the US. And, yeah, I always, since 14 years now, I’ve been related to beer.

Markus Raupach: Yes, remember when I first heard the word Patagonia in connection with beer I think that was like 2014-ish, something like that, and there was this huge rumour that finally someone solved the mystery about the modern lager yeast. And then there was a lot of articles and things going around. I think nowadays we know it’s a bit different. But have you been there at this time? Were you involved in this yeast hunt there?

Juan Ignacio Eizaguirre: Yes. So the discovery, it was made by Diego Lipkin. Diego Lipkin was my advisor at the PhD. So when I finished my degree on biotech, my grandfather at the time, he gave me a newspaper with a note that said, in Bariloche in Patagonia, researchers found the origin of lager beer. And I said, okay, cool. So I check of the name of this guy, and I called him, and I said, I’m finished my studies. I wanted to do a PhD. Can I do it with you? And hopefully, Diego was looking for a person to make a PhD there to understand more of this species, because, at that point, it was a new species. He discovered that and published that in 2011 and I started with the PhD in 2013. So what we do is, was mapping the whole Patagonia from Tierra del Fuego, which is the I don’t know the closest place to Antarctica, to the north of Patagonia, and we isolate around 200 strains of eubayanus, and then we map how was the diversity there, and how is this different population of eubayanus that we found if they were able to produce beer, good beers, or not. So my main thesis was on looking in this genomic new strains and how they can work on the brewing science, and also preparing like hybrids and evolved strains for the industry. So always related with this eubayanus and brewing view.

Markus Raupach: Oh that’s really interesting. And I think one of the big companies, I think Heineken or Carlsberg, they did, then later a beer with that.

Juan Ignacio Eizaguirre: Yes, it was in 2015/16, maybe. I think 15, they seeing the stuff, and then they brew the beer in 16. They call H41 because it is the latitude when it were, is Bariloche, when we found the first eubayanus. And they call this limited beers, wide lager project. And after we found it in Patagonia, in 2011 then in 2014 the same yeast was found in Tibet, China, in North Carolina, US and then appear also in New Zealand, and a few years ago it appear here in Europe, in Ireland. At that point, they brew only beer with the North Carolina one, the Tibetan one, and our Patagonian one.

Markus Raupach: So this yeast must have spread from around the whole world. But the question is, from where? So did you find out the origin?

Juan Ignacio Eizaguirre: Most of the Saccharomyces are found in China. So the main, or the main topic that all the researchers, the yeast researchers, discussing about ecology of Saccharomyces genus is okay, this genus born in China, because we can find all the species there or most of them there. But then, we don’t know when at some point eubayanus travelled from China to Patagonia and it’s really well established there. This year, hopefully in December, we are going to send an article. We are working with some Chilean researchers. They are mapping, they are doing like the same with it in our side of the Cordillera de los Andes in Argentina, they are doing the same. Francisco is a researcher, and they’re doing the same with the Chilean side. And now we’re working together to publish the whole history about eubayanus and it’s really crazy. So what we think is that after at some point this yeast travelled to Patagonia, and they established really well in Patagonia. And then again travel and go to at some point here to Europe to hybridize with the cerevisiae. But we don’t know when or where is the exact point of that, and we are still looking. So last month, we were in the Basque Country with Matthias and Martin and also researcher from Spain, David Perez. He is also another colleague of us. He worked mainly in the Saccharomyces genus, looking for Saccharomyces there in Basque country as well. So we are still looking for this missing part of the story.

Markus Raupach: Yes, that’s like a crime novel. So it’s really very interesting. I think, please correct me if I’m wrong. But as far as I know, I think what we definitely know is there must have been this hybridization around 1600,1610, in the Munich area, where this old or former lager yeast strain came together with the modern ale yeast, which was then coming from the Hanse countries, and then it formed our modern lager yeast. But the question is that this old part, the father let’s say like this, there is still the question where the origin, is that right?

Juan Ignacio Eizaguirre: Yes, that’s right. That’s the hypothesis that we are working on. Matthias and Martin published this hypothesis two years ago or one year ago, I think it was two. But it is really clear that here you have a lot of history that is well-dated, so you can read the books on when the lager brewing started to be a thing. But with the origin of the strain in particular, it’s not really easy to find a spot, because we need to, I don’t know, to discover the time travel to do that.

Markus Raupach: It’s absolutely fascinating. And I think now we come to the point which where we starting 15 minutes ago, maybe the people are already thinking, when do they start to talk about this? So just to let them know, what is a yeast hunter? Is it like Indiana Jones going into caves and having a gun and maybe a hat and doing some secret things and to see a rich guy in the end, or what? How does that work? So maybe you bring us a little bit with you that we can imagine this.

Juan Ignacio Eizaguirre: Yes, yes sure. So at the beginnings, when I start, I start in Patagonia. Patagonia is, I hope that all of you can travel there at some point, if you like because it’s really an amazing landscape, an amazing place. What I mainly do is go into the forest looking for some organic things. I don’t know. Could be fruits, could be insects, could be bark of some tree in particular, soil samples or whatever in the nature. And I always do the same in Argentina, we do a lot of research, and we could identify in which trees you can find mostly this eubayanus. So now it’s easy at the last year there, sampling there, I could take ten samples and find eubayanus in eight of them. So it’s really successful, the method that we use there in the nature. Now that I’m here, and you have a lot of history and a lot of historical places, it’s changing completely for me, because I used to go to again, to the nature and walk really far away from the trails, from the road wherever trying to be really isolate. Because the story that I wanted to take from the nature is something really old. Not an entropic place where humans are eating or drinking, maybe drinking a beer or craft beer, and then they had the yeast there. But here with Matthias and Martin, I’m learning a lot of the historical places where people sitting around to drink beer. So we are not only looking on natural places, we are also looking for entropic places. We were in Schwabach taking samples from, I don’t know, 500-year-old caves, lager places, and it was crazy for me because I’ve never been in those places. Now I’m doing like a working and also, I don’t know, learning about history of beer here. So it’s perfect.

Markus Raupach: Yes, this is totally fascinating. I also have been to Schwabach, and was going with Martin to these old caves. And I don’t know if he brought you to the same place, but one of them, it was like an underneath cathedral. It was huge, very huge place where they were storing the beer and but also smaller ones. And it’s really beneath the whole city, just in the underground and totally forgotten. But it was a great beer city, a city with a lot of history about brewing, and that is really interesting to find this. But in general, if you collect these biological things, do you have to wear special suits or to have special instruments? Or do you have, like, secret boxes? Or how does that look like?

Juan Ignacio Eizaguirre: Yes, so the first thing for me is like understand, what are you looking for? So if you are in the nature, you need to go really in an isolated place where nowhere is or nobody could reach. If you’re looking for an entropic place because you wanted to tell some entropic and historical story about beer or beer brewing, you need to go to these places where they were working on and with which material. And then when you select the place, you need to get some tools, for sure, but it’s not so complicated. You don’t need to use special suits or the Indiana Jones, I don’t know, skirt or whatever. Yes, yes, yes, nothing. But what you need is some sterile container. So that’s the main thing. So you need a necessary container. Could be in a sterile bag, or in a sterile pot or flask, or wherever you have in a sterile that you can find a sterile that is okay. We used to work with storage bags. They are really cheap, so you can buy it, and it’s easy to handle them. Then you need some forceps, scissors, maybe some knife to take the sample. Again, depending on the sample that you are collecting, the tool you are going to use, but in most of the cases, you are going to disinfect, clean the tools really well before the trip. And then in between each sample, you need to disinfect with ethanol and maybe flame it with the burner and that’s it. And then you took the sample, you put it in your bag, a sterile bag, and then we came to the lab. And in the lab, we trying to isolate or cultivate those yeast. You know that yeast, or microbes in general, you cannot see them, right? So we see some yeast when they are like, I don’t know, maybe one million of cells. And then when you have one million, and maybe half a million, you can say, okay, there are yeast there, there’s bacteria there. But if not, it’s impossible. So what we take, it’s just a sample of some organic compounds where maybe the yeast could grow. And then we take this to the lab and incubate it in, depends on what you are looking for. In our case, we need yeast for brewing, so we use just wort, hop wort, and that’s it. That’s the main media we use. If there is something that can grow there, then for sure, it can grow in a beer and then can ferment the beers. So we take the samples, we incubate in this media, and then wait to identify them.

Markus Raupach: That sounds very interesting. So you have all your boxes, and then there starts something. And when do you know that okay, we found something that makes beer? Is it necessary that it looks like beer, or does it have to have foam? Or when do you say, okay, this is interesting? Or do you have to look for everything in the microscope?

Juan Ignacio Eizaguirre: So the first thing is, you need to be patient, right? Because you are incubating some piece of bark that maybe has, I don’t know, 10 cells of some yeast. And then you need to wait until you have one million to see. So you need to be patient with this in this field. And maybe it’s about, maybe, I don’t know, one week to 10 days, you need to incubate the samples, and then you see two different things. But it’s the same as when you brew like a wild or an open, fermented beer. It’s just you need to see some turbidity and some bubbles. If there are turbidity and bubbles for sure, you have something growing on there. And then there are a few rules to identify, okay, this is yeast, so this is bacteria, just looking in the tube, because you know that the cells of the yeast are 10 times bigger, maybe more than the bacteria, so at the end, they can sediment in the tube where you are growing or incubating this sample. So you can see like a creamy slurry of some yeast at the bottom of the flask. And then it’s just starting the old microbiology techniques to isolate in Petri dishes, several media until to get like an isolated colony and then you can identify with molecular methods. In my former lab, we use a PCR method. We need to isolate, extract the DNA, and then make a PCR. A lot of molecular, biological, molecular terms, don’t worry about it. But it takes long. It takes like one week to identify a yeast. And now, okay, this is Saccharomyces eubayanus or whatever. In this case, but yes, I’m sorry, in this facility, the thing is in one day, because we have a machine here. It’s called malitov and it’s working in like, maybe it’s one minute, maybe it’s less. But in one minute, if you have a colony of a yeast, you can say, Okay, this is Saccharomyces blah, blah, blah or torulaspora blah, blah, blah, and it’s perfect. So I’m working with tons of samples right now. I get results really fast.

Markus Raupach: Fascinating. I think during the or after the pandemic, we all know how PCR works. So some learning curves, but so in general, what I’m curious about is I wouldn’t expect that you find like, pure strains. So normally, if you have like a piece of bark or like a dead bug or something like that, isn’t there a lot of things going on, like bacteria and yeast and whatever things? So how do you isolate that?

Juan Ignacio Eizaguirre: So, yes. So mainly you have, it depends on the sample. You could have the three of them, like bacteria, fungi and also yeast. And we used to put some ethanol in the media and if you are growing something in five per cent of ethanol, maybe you avoid most of the bacteria. You can also add some antibiotics to the wort. And then with antibiotics in the wort you avoid completely the bacteria. So depends on the media we are preparing for those yeast hunting. Now we are using three different because we are looking for three different types for groups of yeast. So depends on the media, we use different approach or ethanol or antibiotics to avoid bacteria. Then to avoid the fungi, yes, the critical point is the oxygen. So we need to cultivate it in anaerobiosis or without oxygen. If you cultivate it without oxygen, you avoid most of the fungi, of the filamentous fungi. So then you can also only isolate yeast.

Markus Raupach: Wow, there’s really a lot of knowledge behind and it really sounds fascinating. And afterwards, when you have your samples where you have success. So where something is like fermenting, what is the next step to find out if that is interesting for the beer world, or interesting in scientific ways?

Juan Ignacio Eizaguirre: Well, then is starting the funniest part, I think, or at least the most enjoyable one. Because then you need to brew beer, and that’s amazing. It’s just starting to try, for sure, when you have a name, you know, at least an approach, or the average of capacities of these species. You know, if it is Saccharomyces, maybe it could ferment fast, or should ferment fast, But I don’t know. Maybe you get some torulaspora that produce a lot of esters and it’s also interesting. So then you need to try, we do a lot of trials in a small scale to check maybe the abilities of fermenting the wort. Like if they can consume all the sugars in the wort, or you know that mainly the wort is made by glucose, maltose, maltotriose and then dextrins. Now, with all these non-alcoholic beers around, the yeast companies are looking for yeast could only consume glucose. So they are maltose negatives, because with those kind of yeast you can produce a really small amount of alcohol, and then you can call non-alcohol beer to your product. So this could be one thing. So you check if they can consume the maltose or not. And if they cannot consume maltose, okay, you take it apart, and they said, okay, this could be good for non-alcoholic beverage. And then you continue with the other ones. The ones who can consume maltose. They also consume maltotriose. If they consume maltotriose, they are really now it’s like a diamond to find something like that in nature. It’s not really a thing, because it’s most of the domestication process. The consume of maltose, maltotriose, sorry, in the Saccharomyces genus. So if you find one like the one that they found here a few years ago, who could consume this maltotriose, it’s really important. And then, for me, most important that the sugars is the aromatic profile. Because at the end, you need to drink a beer, right? And you need to enjoy and it should taste good and smell good. If not, no. Nobody wants to drink that. So, yeah, it’s both ways. You need to work on the specifics, sugar consumption, pH level, rate of fermentation, but then also you need to check on the aroma profile.

Markus Raupach: Yes, that’s really a great story and I just imagine is it right if I say, if we look back like 40 years ago, and we have a yeast zoo? There was more or less two or three yeasts in these cages, and now you have a whole zoo with hundreds and totally different ones. And it’s much more interesting to walk around and try this and this. Is that a good imagination?

Juan Ignacio Eizaguirre: Yes. Totally great. But it’s also depending on where we are, right? Because maybe here in Bavaria, it’s like lager beer and Weiss beer, or maybe in this part you can go to, most in the north you get more ale and other ales. But yes, it was ale lager, cerevisiae pastorianus and that’s it. If you move to other countries like Belgium with the somewhat spontaneous fermentation, you get some brettanomyces. You also get some others. But really seldom, really rarely. So mainly it was like cerevisiae pastorianus ale and lager. And now, not only we as researchers or yeast researchers, but the companies, they have, if you check now, I don’t know, some Lallemandm Fermentis, yeast companies they have also offer you lachanceas, brettanomyces. There’s also some companies, a smaller one, liquid ones that they offer you, metschnikowia, torulaspora. Here in Weihenstephan we use also torulaspora, also Saccharomyces paradoxus. So it’s, yes, there are plenty of them. And all of them are different, and they have different profile. And then it depends on the hand of the brewer, how to shape the beer that they want with a new product. And for me, one of the most fascinating stuff is like, what something that we do, we did in Argentina, in Patagonia, is you can really have your own local yeast isolated from your environment and you can tell nice stories about that.

Markus Raupach: Yes. Did you hear about the Rogues Beard Beer?

Juan Ignacio Eizaguirre: Beard Beer, yes.

Markus Raupach: Yes. This is a very local yeast, I think.

Juan Ignacio Eizaguirre: I tell Martin that we should do the same with his beer.

Markus Raupach: Yes, why not? So for all the listeners who don’t know, Rogue did a beer with the yeast isolated from the beard of the master brewer, and it turned out to be a very good beer. It was very fruity, very interesting. So I was very fascinated. Unfortunately, they didn’t continue it, so I only had two bottles. But it was really a great experience. And so you can really do a lot. Maybe something also, which is quite around now in the beer world, is this northern yeast, like this Kveik yeast or strains. I will also go to Norway at the end of this year to be at a congress and a Kveik festival thing. So is that also something which belongs to the yeast world you were talking? Or is that a little bit apart?

Juan Ignacio Eizaguirre: Yes, for sure. It’s all they somehow from Norway are really fascinating, and it’s in, I think, when they started, not when they started, so when they, they came again to the brewing world and it was crazy, at least in Argentina. I know I was working for a few breweries, consulting in a few breweries there, and they were in love of this Kveik yeast, because you can brew really fast, you can brew like a really standard product. And so at some point, several breweries were using this Kveik. And for me, it was crazy. The first time when I read about this Lars story on the Kveik, I remember that I got this book from Michael Jackson, and he mentioned that. And he mentioned that in 1997, something like that. He talked about the Kveik yeast, but we never used it in the industry. They started in maybe 2016. So 20 years after that. So it was crazy for me.

Markus Raupach: I didn’t know that. And I did also a BierTalk with Lars and he told the whole story. But this is new. Interesting.

Juan Ignacio Eizaguirre: I will send a photo of the book. I have it, but yes. Well, two years ago, the first time that I came here to Germany, Matthias and Martin invited me to go to yeast hunting to Georgia. We went to the Caucasus. For me, everything was crazy because I couldn’t read the things, because they have this own way to write, and they speak another language. It was completely crazy, but it was so fascinating, this place. And we were taking samples in the nature in the Caucasus, but not only the nature. We visit four small villages. I said villages, but maybe it’s less. I don’t know the English word for that, because this was like maybe 10 houses. So it’s really a small place in the mountains and each of these places has its own brewery there. And they brew a beer with a copper basil. They said they have like, 300 or 400 years old, these basils. They brew a beer completely in a different way that we know now and then, how it’s brewing in the modern world. They used to grow the barley therein the mountain. They malted in the brew houses, in the roof of the brew houses, and they prepared the beer. They mill it, and they prepared the beer with that. But one of the most crazy things that we learned there is in one of the village they use not the Kveik with the good wooden ring stuff like in Norway, but they dry the yeast in leaves. So they have a plant with huge leaves and they take the foam of the fermenter in the second day, they said, the second or the third day where it’s really, the activity is really high, they took a spoon, a copper spoon, they collect the foam and then dry it in that leaf, and they hang it until it’s dry. And then they put it in a small wooden box and use it the next year for the next season of beer because they have only three months where they can brew beer there. So for me, it was fascinating. We are now working with some of those yeast to understand what happened with them, and if they also could be some family of this Kveik.

Markus Raupach: Yes, that would be interesting. That would be like a southeast strain because the normal Kveiks are left and right of these mountains in Norway. And this is really a great story. Wow. And also Martin and Matthias, they told me that in the former times, the idea was that those people who wanted to brew, they had to walk into the forest and stay there for a while just to be there, like a religious ceremony, and then they came back and then they started their process. And they were thinking that probably when they went to the forest and they lived in the forest, they took some of the microorganisms, yeasts, and brought that back, also in the brew houses. Is that like a makeup or do you think that’s also true?

Juan Ignacio Eizaguirre: It could be, could be. When they tell us the story, it was crazy. But we heard so different stuff there. That’s why not. They tell that they go into, they went to the forest for, like, I know, one week or one month, something like that. And when they came again, they can produce this beer. It could be, it could be that they get some of the yeast, but also could be because what they tell us also is that they should avoid the meat and all the diseases that you have when you kill some animals or whatever. So maybe it’s also part of the trick. Avoid the infections and then get clean to produce a beer.

Markus Raupach: Yes, it’s definitely fascinating how these old practice and things evolved and how it was also combined sometimes with religious or at least spiritual things, or ceremonies and things like that. So by the way, I read that you are also brewing beer in Tibet. So what is the story behind that?

Juan Ignacio Eizaguirre: Ah, no, no, no. We had a brewery with friends in Argentina. It’s called Tibet.

Markus Raupach: Ah okay, sorry.

Juan Ignacio Eizaguirre: No, no, no, I’ve never been there. I would love to be there. Hopefully, sometimes I can travel to do some yeast hunting in China at some point. But no, there was a craft brewery in Buenos Aires, and I was the brewer there when I finished my PhD.

Markus Raupach: That’s a nice mix up. But also interesting. Is this brewery still there?

Juan Ignacio Eizaguirre: In Argentina?

Markus Raupach: Yes.

Juan Ignacio Eizaguirre: No, it’s closed with the pandemic.

Markus Raupach: Not an easy time.

Juan Ignacio Eizaguirre: No, no, no.

Markus Raupach: All right, and I read another thing, the proyecto, your career. So what is that?

Juan Ignacio Eizaguirre: Yes. With this also, it’s with another colleague, Marcos Ricardo, we started this consulting company when we were, I don’t know, into something 17 or 18, something like that, to help brewers. At some point, there was a lot of small brewers starting to establish in Argentina. So we help with the quality and also recipes and wherever.

Markus Raupach: So you would say your main job now is to be a yeast hunter.

Juan Ignacio Eizaguirre: Yes, yes. So now it’s a yeast hunter and also itake here at the Weihenstephan several projects, several things going on in the beer world. And it’s crazy. I’m really glad to be here.

Markus Raupach: If you find successfully some interesting yeast, so for example, I also made a talk with Matthias about the non-alcoholic beer the Lasser Brewery does in Germany, which is made by a yeast strain which was found more or less by your team. How does that work that you make sure this is something like your finding? So can you patent a yeast. Or do you make like a copyright? Or, how does that work?

Juan Ignacio Eizaguirre: You cannot patent the yeast because it’s nature, but you can use it and then depends on where you are, who is the one who has the rights on that. We were to Spain in the last month, and with the Nagoya Protocol, all the yeast that we harvest there or we isolate there are from Spain. We for sure, can use it for research. But if there is some commercial thing, they need to be part of the project. Then depends on the regulation of different countries, because in South America it was completely different, and all the rights were from the research council. So if you work for this council after you discovered something, it’s not yours or not from your lab, it’s from the council. So you know it’s more complicated there. But here it’s really easy. You need to try, you need to use some yeast that you know that it was in former time used in other beverage or in other foods, so it’s safe, and then it’s just trying to get the best partner for your beer and it started to brew, and it started the trials.

Markus Raupach: And this is an interesting aspect. I think if, how do you make sure if you find some new yeast or microorganism that it doesn’t produce some byproduct, which is maybe either not healthy, or maybe like drugs or things like that?

Juan Ignacio Eizaguirre: Yes, in yeast it’s not so common. If you have bacteria, you have these biogenic amines which are really complicated, and it’s not nice, so you need to avoid those. In yeast it’s not common, but if there is really a strain yeast, you should avoid that. So we know there are some genus that they are really established in the food and in the beverage world, fermenting world. So we know that if we found something regarding this genus, it’s okay. And there are a few trials that you need to do, and that’s it. But it’s also a thing that is not so well documented, because at the end you are not eating, in most of the cases you are not eating that yeast. So for example, in the non-alcoholic beer, you need to pasteurize it because if not the product, it will be explode if they get the Saccharomyces or an ale yeast from your brewery. So you need to pasteurize at the end. So if the product is pasteurized, you have less concern. Means that you need to demonstrate. But if it’s not, then, yes it is more complicated, and then you need to do more trials. But most of, again, most of the yeast, if they are found in, they were found in some, I don’t know, fermented food or fermented beverage, they are considered safe.

Markus Raupach: Okay, so no new magic mushrooms. You never know. All right. Yes, and if you look back to your work in the past years, so was there one yeast or two, or maybe several ones where you would say, okay, this was really a great thing we found or I found or we could get into the brewing world?

Juan Ignacio Eizaguirre: Well with the eubayanus it was really successful, and it was really nice all the work behind that, because at the beginning, so you are a brewer. So you know. If I tell you that I have a yeast that is not flocculat that could, it takes really long to ferment, maybe 10 to 15 days to ferment that produce phenols and that cannot consume all the maltose in the wort, you probably never choose that, because it has a lot of complaining and a lot of different things that they are not really good when you’re thinking on a brewing yeast. But then it was a lot of work, or we have to do a lot of work to try to put that yeast in the brewing industry. So trying to decrease the phenolic compounds, trying to increase the rate of fermentation, also improving the flocculation, so there is a lot of work that you can do with yeast. And there is this technique, it’s called experimental evolution. It’s a kind of domestication, the same kind of domestication that brewers did for thousands of years. But in the lab, you can do it really fast. So I get, like with one of the strains of eubayanus I get 500 generation in two years. At the end, we get a really, really successful yeast for the industry. So I think this was one of the most enjoyable strains that I used. And here we have a lot of promising yeast, some lachanceas that ferment really fast. They are really, really neutral in aroma. So it could be really interesting to grow with that. And also a few starmerellas that produce a lot of esters, and also some like rose compounds, but cannot ferment maltose. So it could be for the non-alcohol beer. So yeah, there is a lot of things that now we are working on.

Markus Raupach: Yes, that’s also something I learned now that you use the yeast more or less as like a raw material, and then you try to domesticate or to make new generations which have new aspects, new things that make them even better or more interesting for the brewing world. So there’s a lot of work, also of your work afterwards into it, until it comes into the brewing world. That brings me into another question on that, when I was in the States, they do a lot of genetic engineering with yeast, which is not allowed here in Europe. But do you know if they also use some strains like you have? So some like wild strains. Or do they more or less work with the classic strains and bring their engineering into them?

Juan Ignacio Eizaguirre: I think both ways. So they have these GMO, okay. So they can, for those they use mainly like commercial strains, they’re really robust, and they know perfectly. So they can only get the mutation in the gene that they want, and that’s it. But they also, there are a few worts and a few companies working with wild yeast. So I think it’s both. So the Philly Sour from Lallemand, it’s isolated, it was isolated in Philadelphia. So it was also, it was also from the one. So and also in North Carolina there in the University Madison, they produced a few beers with eubayanus, the eubayanus isolated from them. So there are a few nice projects in the US as well with wild organisms.

Markus Raupach: And do you have a personal opinion about this genetic engineering?

Juan Ignacio Eizaguirre: For me, I’m a molecular biologist, so I always learn how to do the modification in the genomes, because it was my first duty. I think it’s okay with the new systems that we have, like this CRISPR Cas9 that you only make, only one change, and at the end it’s just my belief, right? At the end, you are just trying to do faster the evolution in that try at least. So if you, I don’t know, you have a strain when one of the cases is omega yeast, they produce this yeast, it was a Hefeweizen and they silence so they break this puff gene, one of the puff gene. So now it’s only the banana aroma. And it’s interesting because you have now a different background in the beer. So also in eubayanus, there are a few worts. They did eubayanus without phenols with this system, with the CRISPR Cas9 and now we know more and more of the background of the cells. So maybe 20 years ago, the ways to mutate a yeast were completely different, and you need to put a lot of antibiotic resistance to select, then the yeast that you want, and that for sure I should not do it. I will avoid that. But with these new systems that you can also sequence the whole genome from the origin and then from the mutated one, and you can check and you can prove that it’s only one base difference, okay, I think that that’s okay.

Markus Raupach: It’s like with all the other raw materials, you really just find out how huge the potential is in the beer world. And somehow I find it good that we have this protection in Europe. On the other hand, I had a lot of GMO beers in the US or in the UK, where they somehow get the yeast into the country. Don’t talk about them, but they do. And so that’s, but in general, what is really fascinating is that you now can have a lot of aromas just by using the right yeast. So you could even brew without hops and still have a lot of hop aroma and all these things. So I think there is a lot of potential and a lot of opportunities. Also, if we look on the challenges we have on the hop side, on the malt side with the climate change and everything. So I think that’s just another option.

Juan Ignacio Eizaguirre: Yes, yes, yes, for sure. It’s a tool, really interesting tool and now we know how to use it. So it’s, I think it’s completely okay. And also, for this yeast that you mentioned about this, trying to, I don’t know, to decrease the amount of hop that you use in beer, like all the thiolized yeast, but I think it’s perfect. I think it’s perfect. But then, because I also in Argentina, I try a lot of these beers, and then at some points you need, you know, it’s like everything. It was like, okay, all the beers now have a lot of styles. Maybe we don’t need so much less.

Markus Raupach: Yes, it’s a little bit like when all these IPAs started, and then you only had IPAs. So some 50 shades of hops and now you have all this thiolized yeast and at the moment, for me the same in the competitions, I always detect when you have a thiolized yeast. But maybe there’s also some ways to go. So yeah, maybe to the end, let’s talk a little bit about your beer judgings. So you are a BJCP judge, and you were judging just in Argentina right now? Or also in other countries?

Juan Ignacio Eizaguirre: I get the national ranking this year. So I now I’m also grading exams for the BJCP. And I used to judge in Argentina a lot, in Chile also, I did it twice, and in the US, only one. And here in Europe, not yet. Hopefully, I could find someplace to go. It’s a really nice job, I would say. And you also learn a lot. It for me, was really, really good for my, I don’t know, for my skills in the brewing science sector, when I started with the sensory approach, because it’s a tool that all the brewers has inside the brewery and inside themselves. So I think it’s really important to manage those skills.

Markus Raupach: Yes, and it’s also a job with a lot of fun and where you can meet a lot of people and see a lot of places. So definitely that’s good. So maybe we find some ways that I can bring you into some European competitions. It would be great. So thank you very, very much for this little insight in your great work, in your great job. And also thank you for that. It’s very important that we have people that do that and bring our beer industry forward. And I really wish you all the luck and maybe you find some more interesting special yeasts. And yes, great. Thank you very, very much.

Juan Ignacio Eizaguirre: Hopefully well, thank you, and thank you for communicating, because this is the most important thing. We can do a lot of work from the science, but we are not always the best guys communicating that. So it’s really glad to have people like you doing that. So thank you for this invitation for the talk. It was really nice. Hopefully, we can sit together and drink a beer and celebrate with some wild yeast from the yeast hunter project.

Markus Raupach: Oh yes, we will. Thank you.

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