Ep 45 - Can You Solve This Issue #2 - With Tuur Mertens

Can you solve a real brewery issue?

Tuur Mertens brought us a real life “gushing” problem faced in a historic brewery.

We share the symptoms and context…

But can you diagnose the root cause and the fix? Test your skills in this weeks episode.

How to play:
•⁠  ⁠Listen and take notes
•⁠  ⁠⁠Email your answer (root cause + fix) to chris@brewresourceful.com
and tuur@craftsense.net

We will share the correct answers on LinkedIn and a follow up post

Chapters

00:00 Introduction and special guest
01:37 Meet Tuur Martens
02:31 Tuur’s research and approach
03:37 The brewing mystery setup
05:20 Inside the brewery: process and constraints
07:31 The gushing problem: investigation begins
12:37 Breakthrough in the case
15:27 Can you solve the mystery
16:24 Wrap up and next steps

Show sponsor - Brew Resourceful

Transcript

0:13

Hello everyone, and welcome to the latest episode of the Modern Brewer Podcast with me, your host, Chris Lewington, and with me throughout today's episode. It's a very special episode. It's Tuur Mertons, a former quality manager at a prestigious Belgium brewery who's brought with him a fascinating quality mystery to solve. That's right. Folks, the most talked about episode is back, can you solve this brewing problem? The real ones. We'll, remember all the way back in episode 18, which was one and a half years ago, I shared a real life brewing problem that came across my desk. Since then, it is the most talked about episode. People constantly coming up to me at events saying, I love that style. Can you give us more problems? And I ignored them for no reason whatsoever until now. I actually met at the Brewers Congress in London recently. Brought me this direct problem that he'd faced, and since then we've been DMing back and forth and I am just buzzing to get this out there. I'm so excited for you all to hear this. It's a doozy. So first I'd like to welcome to the show Tuur Mertens. Thank you for the introduction, Chris. Tuur, thanks so much for coming on the show. First, let's get the listeners knowing exactly who you are and what you do. Yeah. Hi. I'm Tuur Martins from, from Belgium. I, I'm very passionate about beer, ever since I was a student, so I decided to make it my career and I did a doctorate in brewing science. So my topic of my thesis was, about improving beer flavor stability. After graduating, I co-founded together with my partner Nina, Craft Sense, which is my, my company, where we give advice to brewers and food companies alike. That's amazing. Congratulations. we speak about this a bit off air as well, I know what it's like to go out on your own, so I have a lot of respect for it. I know it's, it can be a bit daunting at times, but also very exciting, so yeah, great looking it. Tuur, am I right in saying that you, your research led to the product development of something? yes. So, During my PhD research I discovered that pomegranate extract is able to, capture iron during brewing, which is then able to prolong shelf life quite substantially. And this actually turned into a, a market product called Mesh Life that Murphy and Son is now, selling. That's amazing, man. That's actually so good. Yeah. I, I spoke to. I had Dr. Greg on two episodes ago, Dr. Alice Kin on last one, and we were talking, I think in both episodes, like one of the pinnacles I for it seemed to me for people who research and scientists, is that not only their research gets applied into a practical scenario, but actually then it gets commercialized into a product that's like what every scientist seems to dream of, right? At the beginning of the PhD, I always set that as a goal. Like I wanted to be practical. Like I, I, I'm an engineer, I want to be of use, so I'm very proud and happy that there's something out there like helping, helping out. It's, it's amazing, man. Congratulations on that. okay, well let's get into this episode Terrace. Over to you. I do want to make clear before we start the episode, something important, namely that this case that we will be talking about today, it involves a real brewery. Namely, bro Rayon Steinberger. It's a well-known Belgium brewery with a long history and a strong commitment to quality. So I do want to point out that I, reached out to them in advance to ask for their explicit and formal permission to talk about this story.'cause as you know, it sometimes can be a bit sensitive to talk about quality issues. So, but they granted their permission. so a huge. Thank you, to them for their openness and their contribution to this brewing community. And they, yeah. We hope that brewers listening to the podcast, to this podcast can, learn from this experience and that the brewing community has some value in this. Yeah, it's it's amazing. Tert, thank you so much for bringing the problem and. To the brewery for allowing it. that's what this is all about really, isn't it? It's kind of like sharing those problems so the brewing community can learn from them. And I Exactly. a really admirable thing to do because as you rightfully said, quality can be quite a, I don't know, sensitive Hmm. for brewers. So to be able to share this is actually excellent. So yeah, thank you so much for that and getting that permission. And thank you to everyone at the brewery as well. Okay, so I, let's get into the episode. Let's go. I love this. Let's go. So, this is your problem you brought to me, so I'm gonna let you do all of the talking here and I'll come in at the end. So good luck everyone. So, as I said, this problem comes from my time as the quality manager at Steinberger. Some info about the brewery. it's a family owned Belgium brewery with a production of around, 180,000 hectare liters of beer per year. The brewery is quite old. It was founded in 1784, located in East Flanders, and it is known for their strong high gravity Belgium Ailes. A lot of them have secondary fermentation in the bottle. Even though they are, quite old, they have a modern, semi-automated stainless steel brew house consisting of a mesh and a lot ton boiling kettle, and a whirlpool. Now fermentation, standard happens in large. cylinder conical tanks at temperature of 22 to 25 degrees, so quite high, and this is for their top fermenting beers. After fermentation, most of the yeast is removed via centrifuge. So, after removal of the yeast, the beer goes into lagering tanks for lagering. And this happens at a temperature of around zero degrees Celsius. And this is, again, followed by a yeast removal step, often by centrifugation, but for certain beers also, plate filter filtration is possible. So, the brewery makes a diverse range of different beers and several of them, are naturally carbonated through this secondary, fermentation in package. So the way this works is that, fresh yeast. Together with some vert is added to the bottle together with some priming sugar. After packaging, the bottles are moved to a warm room where they are matured for two weeks at a temperature of 20 degrees Celsius. To complete their secondary fermentation before leaving the brewery, because some yeast still remains present in a bottle. These type of beers are also, often referred to as being alive or living, So. That's the brewing process in a nutshell. during my time as a quality manager at the brewery, there was a very confusing but persistent quality problem that started showing up. So every once in a while we would get reports from customers about bottles. That would show gushing. Now, gushing is what happens when when you open a beer and you see foam overflowing. This can sometimes be pretty violent, but sometimes you just see a steady stream of foam, but this results in beer loss and it's not so nice for the customers. It creates a mess. So it's not something that a brewery would want. But the problem was, it wasn't predictable. We would go months without any complaint, and then suddenly we would get three complaints in a week by three different customers. three different situations, but the same issue. Now we would always, when we, whenever we would get a complaint, we would go through our archive. We would always store, three bottles whenever a batch was filled for situations like this, and we would go through a full, quality control check. We would measure, again, the CO2 levels, the gravity microbiome analysis, sensory pH packaging, the whole gist. But whenever we would do this with these gushing complaints, we would, could never reproduce the, the problem. Our quality control sample would always be perfectly inspect and would never show signs of gushing. So, there was no pattern, no reproducibility, no really red flags in the data. So at that stage, we would often attribute it to, bad consumer handling. So maybe the, the customer, transported the beer a bit roughly or stored it badly. Maybe the beer came out of the freezer, had some ice crystals that would cause it to gush, However, when I would talk to some, veteran team, members of the staff about this problem, they would mention that they came across this specific problem, a few times in the past already, and specifically that it would be only a portion. Of, the packaging rung that would show this gushing problem. So that was quite puzzling. So the beginning of a batch could be fine, that a few crates would gush, and then it would be fine again, so that they had noticed this in the past, but they could never really figure out where it was coming from. So this problem intrigued me, so I kind of made it my, quest to solve this. So, so that meant that we would have to start looking at internal processes that were time dependent and would have to be specific to the filling process. so we started eliminating a few of the obvious, suspects. Like could it be over carbonation perhaps, because we would be unevenly, dis distributing the priming sugar or the yeast, but, the priming sugar, no.'cause it would be added during the, at the bright beer tank stage and it would be homogenized. So that, that was not really, Possible. When we would look at the yeast dosage rate, we didn't see any fluctuations there. So also that was of the, of the possibilities. Also, whenever we, have a batch, we would measure CO2 levels before it would be shipped off, and those were always within specifications. So over carbonation was scratched out, So could it, could it have been contamination also here? no. We rarely, if ever, detected, organisms in our beer and, we always tested them. If, if you would find organisms, it wouldn't leave the brewery. And the samples were always tested. Sensor as well. I mean, never had any off flavors. So packaging faults that there was a working theory for a while, but. We would see gushing complaints with new bottles, but also with reuse bottles. And every bottle would be rinsed before filling and whenever inspecting a batch, we could never see any scratches or marks in the bottle. So that also, that theory also quickly died out. Now raw materials can also be a big source of gushing. So if, if you use malt that has a fungal infection, it can produce hydrophobics that, create nucleation points and that cause violent gushing. But the violent gushing doesn't really match what we heard from the customers. For one. And we also always used, raw ingredients from well-respected companies that are certified. So no, that didn't seem plausible as well. Our water was RO treated and we would add salts later on, one of which would be calcium chloride. honestly, at this point we didn't really have, much to go on. We were a bit stuck. we didn't really know. Where to look until one day we got a lucky break. one of these gushing complaints came in again, but it was from someone from the area. So I convinced the customer to bring a few bottles at the brewery. And finally we had, in our hands, a faulty bottle. So, we treated the quality control sample. The customer complained bottle, in a similar way. We chilled them, opened them, and lo and behold, the qc ca sample didn't gush and the customer's bottle did gush. So then and there we really had, we saw that the problem was real and something must be going on that didn't show up in our quality control screenings. So what we did then was, we poured, put, we poured, put bottles gently. we decanted them, left about one centimeter of the liquid behind, give it a bit of a swirl and put a few drops under the microscope. So what we saw, there was a big clue. The QC bottle was clean apart from some standard yeast sediment. We didn't see anything out of the ordinary, but the bottle that was gushing was full. The sediment was full of angular crystalline particles, so it was noticeably different from the QC samples. So that was a big, big crew. So now we, we finally had something to go on, so that was the cost of the gushing, but still. The question remained to the root cause, like why was, did we find these particles only in the, that specific bottle? Like why wasn't it the case for the whole batch? Why only particles in a packaging window? so the, the word was the same, the sister was the same, the batch was the same. Everything was the, except this wasn't why. So I'm stopping here for the audience to try and puzzle this out. Oh, mite. Oh, I remember when you first told me it, I was like, huh. And there's all the information there to solve it. And you were like, yep. And I, I, yeah, it's good. a good problem and it's good'cause it's real world and like, I always think the most challenging problems, the ones that aren't linear, there's not like one batch that has it's parts of the run that were affected. That it really starts to be like, what? Like how? so yeah, this is a fantastic. a problem for someone to solve. So the big question is, can you solve this issue? I'm gonna split this into two. So there's two, let's call it points, whatever you wanna call 'em. Gold stars without no sounds too condescending, doesn't it? And we'll just call 'em points. But the first point on offer is what were the angular crystalline particles in the gushing bottle? That's the first question. The next one is, and there is a lot, do you know what I call it? A thousand points? If someone, if, if anyone gets this. but there's a thousand points on offer if someone can tell to what was the root cause of that issue. If someone can find that. That is a thousand points I'm gonna say there, and you'll be read out as a leaderboard. you'll be 999 points above anyone else who gets the first part of that question. So there's two questions on offer here and 1,001 points apparently. it's completely arbitrary scoring system I've literally just made up. but yes, I am extremely excited to see if someone can get this. So on the next episode tour, what we're gonna do is we're gonna have a little chat about the problem. gonna ease it. I'm gonna try and get some stuff out of you, see if people can guess it whilst they get there. And then you're gonna do the big reveal on the next episode, which will be. Just after Christmas time, most likely. We'll, we'll get that out there in that little Christmas break. So what I'm gonna do is I'll leave a couple of email addresses in the show notes. Please send an email to us both with your, with your first answer for the first question, Which was what were the angular crystalline particles in the gushing bottle? And then the second question is, what was the root cause of this issue? Okay, so we'll all see you after the Christmas break. please send those answers to. You can also of course, DM me on if you don't want to email for whatever reason, you're just on your phone already, like, feel free to DM me on Instagram. Feel free to DM me on anything on LinkedIn. same with Tara as well. All of his contact details are in there. And then on the next episode, if you get any of those two questions right, I'll give you a name, a big shout out and, good luck to everyone. I hope everyone here has a great Christmas. thank you so much for listening and thank you so much Tuur, for bringing this problem to us and I can't wait for the big reveal on the next episode. Yeah. Thank you, Chris. I'll catch you on the next episode of the Modern Brewer podcast.