Process Control of DMS in Lagers with Dr Greg Casey – BeerSmith Podcast #317
56:10 Share

Dr. Greg Casey joins me this week to discuss DMS management in American beers. This is Beersmith Podcast number 317. ♪♪♪

This is the Beersmith Home Brewing Show, where brewing great beer is our passion. If you want to take your brewing to the next level, visit beersmith.com, where you can download a trial version of our Beersmith software, subscribe to the newsletter, and get dozens of free articles on home brewing. And now, your host and the author of Home Brewing with Beersmith, Brad Smith.

This is Beersmith Podcast number 317 and it's early January 2025. Dr. Greg Casey joins me this week to discuss DMS management in American beers.

Thank you to this week's sponsors, Craft Beer and Brewing Magazine. They recently added a new collection of more than 500 beer recipes from pro brewers to their site. And most of them will let you download the Beersmith recipe file. The new Craft Beer and Brewing recipe site is at beerandbrewing.com slash beer dash recipes. Again, that is beerandbrewing.com slash beer dash recipes.

And Beersmith Web, the online version of Beersmith Brewing Software. Beersmith for the Web lets you design great beer recipes from any browser, including your tablet or phone. Edit recipes on the go with access to the same full suite of recipe building tools as our desktop version. Try Beersmith Web today by creating a free account at beersmithrecipes.com. And finally, a reminder to click that like and subscribe button on YouTube, iTunes, Spotify, or whatever platform you're listening on. Clicking those buttons is a great way to support the show.

And now let's jump into this week's episode.

Today on the show, I welcome back Dr. Greg Casey. Greg has an extensive history in brewing, including Carling O'Keeffe, Molson's, Carlsberg, Anheuser-Busch, Stroh, Coors, Molson-Croers, Miller-Croers. He holds a PhD in Applied Microbiology and Food Science and was the 2001-2002 Chair of the Education Committee of the Masters Brewers Association and President of the American Brewers Society of Chemists from 2005 to 2006.

Greg, it's great to have you on the show. How are you doing today? I'm doing great. Thanks for having me, Brad. Appreciate it. A pleasure to have you. I think we last had you on in September of 2023, which was a while ago, episode number 288, if anyone wants to look it up. But I know you're working really hard on your five-volume set on American Lager, so I was hoping you could bring us up to date on that to start with. All right. A little show and tell.

Here's the first puppy. Oh my God. It's a book. It's a book. It's eight, you know, 11, eight and a half hardcover.

It's the first volume. It came out in August last year. Second volume has been printed and it'll be out very soon. No later than the end of next month, I would imagine. And I'm working on the third volume, which is Germany's history with the use of rice and other adjuncts for the brewing of lager beer for domestic consumption in Germany.

I had to go there. My 16 years of research, now 17, said you can't tell our story, America's, without telling Germany's story because there's such an interaction between the two. So, yeah, I'm really gratified that it's now a tactile experience.

Yeah, I mean, you're working on the first two volumes. Can you cover the first two volumes since they are out or just about out now? Yeah, the first volume is, you know, describes, you know, there's so many myths. And the first volume is about the beer of myths and legacy denied, I call it. So it gives the reader a perspective on the history, not so much of American adjunct lager beer,

covers the period from the 1840s to 1940s in the United States. And there's so many myths about when corn and rice started to be used in the United States. Most of them center on World War II era. So the first book introduces the reader to what to expect from the five-volume series. It outlines many of the...

myths that are associated, gives the references. And then the legacy is denied. It's a big part for me because I'm an immigrant myself. So many of these immigrants fought really hard in the late 1800s before Prohibition to defend the right of the American people to choose the beer of their choice and the brewer to brew the beer of their choice, not to have it legislated. So

That's the first volume. It's kind of introductory. Then the second volume deals specifically with the period of 1941 to 1948. For World War II buffs, you go, okay, didn't it end in 45? Well, yeah.

You know, in terms of addressing the myths on a year-by-year basis, the hardest thing to get during World War II, especially when the United States, the Commonwealth countries like Canada and Australia were feeding former enemies food to keep them alive.

alive because the supply chains were so blow up. It was really difficult to get corn rice in 46, 47 and parts of 48. So we go into the real history, if you will, at least I like to say it's real. It's all in terms of reference period documentation, you know, the use of tapioca, cassava, potatoes, sorghum grains, raw barley, barley flakes, just desperate to get adjuncts to the point.

When corn and rice was short, some breweries, many breweries in the Midwest in particular, shut down rather than brewing all malt beer. No kidding. Yeah. I mean, it had that beer. Our beer had been so long established, adjunct lager beer, that it was considered unsaleable. So in some ways, to summarize...

So this last 17 years of my life has been a process survey, if you will. And it's a term that will come up in connection with DMS. But the process in this case is that 1840s history. And just a little anecdote in terms of history.

how this publication through the MBA helped. And I gave a talk in 2019 at New Belgium on this research. At that point, I wasn't thinking publishing, whatever. But I gave a talk. It was mostly craft brewers. And I had somebody come up to me from the Brewers Association afterwards and say, hey, you've got to be publishing this great story. So I said, sure. Okay.

So I approached the Brewers Association thinking, well, let's see, because my real audience, biggest audience in the industry is the craft brewers. And I approached them and there's some interest, but then I guess their process is, you know,

Yeah, beer, you know, accredited authors have already published with the association. We'll take a look at the proposal and deem it whether it should be published or not. And I got a resounding no from that. OK, necessarily surprised. But I was referred to John Palmer.

you know, would he be in the MDAA? So I think, you know, from a process survey, what my findings were really went against paradigms, I guess, in terms of the history, just as relative to the upcoming topic here.

The paradigms on process control for DMS are very different than mine, and we'll get into that a little later. So that's it. I just want to cover, so you got the first three volumes under where you're working on right now, and are you still at five volumes? Are you going to do two more after that? Yeah.

Yeah, there's two more after that. The third one is Germany again. It covers particularly the period during the German Empire and the Weimar Republic when adjuncts, particularly in the Weimar Republic, were using rice and corn at levels we had been using prior to Prohibition to brew beer for domestic consumption because of runaway inflation. Anyhow, but the fourth volume is all about our history. Yeah.

You know, the inspiring history of the development of the world's now most popular beer, but the innovations and materials, process, technology, designs, the entire supply chain to deliver to the American consumer of 1870s to, you know, 1919 as a lager beer. And that's fourth volume.

The fifth volume is the inspiring defense, is every institution of power from Supreme Court, every level of government, federal, state, local, press, medical profession, enemies within, if you will. The list goes on and on, particularly barley growers and molesters, if you will, for obvious reasons. And they try to shut it down.

And it's a fascinating history. So, yeah, I think we, I think we discussed that in one of the previous episodes that there was actually a push to have a Ryan, Ryan Heitzke boat here in the United States, right? Yeah. They didn't call it the Ryan Heitzke boat, but ironically they, cause that really, the Ryan Heitzke boat, um, wasn't a term I couldn't, I found it earlier than has been published in terms of when it was used in a beer context. Um, and it was just before, uh,

you know, the first world war. Um, and it was in connection oddly with use the ban on saturated for top fermented beers in Germany had taken place in 1898. And this guy was trying to get a compensation because his processing aid was denied. Uh, when the national Ryan high school boat in Germany happened on June 3rd, 1906. So, uh, yeah, it's, it's a cool history. Um,

And just there, and it was ongoing. This wasn't intermittent. This was half a century of constant attacks on the industry. Overwhelmingly, Germans stopped using adjuncts and passionately defended it very publicly, very, very publicly.

And they won the day. So that's part of why, you know, that protecting the right of the brewer to brew and the consumer to choose, that's a story I think that really should appeal to all Americans and in particular craft brewers who are using a lot of really interesting ingredients in their portfolio. Yeah, well, I'm looking forward to hearing, you know, the last couple volumes as well when you get those published. But today you wanted to talk about your title you gave me was Process Control for DMS.

reflective and purely American perspectives. So first of all, tell us a little bit about what DMS is. And second, why the word reflective fits in here. Okay. Yeah. Thank you. Yeah. It's a little unusual term, right? To have it a title, but in terms of your first question, DMS is,

I refer anyone interested in the subject, the podcast you had with Charlie Banfor, DMS, was epic. He's the guru when it comes to science. I'll put it in the show notes for folks who want to go back and look at it. Yeah, show notes, refer them to that. But I'm not a chemist, right? I'm an applied food scientist, microbiologist.

But dimethyl sulfide, as I remember telling to a guy in a brew house when I first started at Coors, dimethyl sulfide is an S with two methyl groups. I got this blank look and I went, okay.

Let's try to get this to, you know, what is DMS? Where does it come from? And it led to only using terms not like SMM, but DMSP and DMS to many people across the supply chain whose education, nothing wrong with it, was high school, but they made gores gores. And they made it a strong company over decades, which I always thanked them for. Sure.

But the reflective part to answer that question, you know, when I look back at my career, first of all, this will be the last podcast, public speaking, I do on my former life, which was as a applied brewing scientist. Sure. Those days are done. So this will wrap it up. You're retiring now? Yeah.

Well, I retired in 2013 from Coors, but I've been dedicated full-time to that five-volume project. Of course, yeah. It's a blessing. So I'm retired, but I made a conscious decision many years ago to reinvent myself in retirement, specifically as a brewing historian. But back to Reflected. I remember it's 50 years ago this fall, 1975.

Start at the University of Guelph, and I'll never forget the professor standing behind the desk there in the front saying to us young bucks, everything I'm about to tell you is what we think we need.

Don't forget that. Always filter it in the perspective of this is what we think we know. That kind of kind of rocked my world. I was like, well, it's got to be the truth. Right. So that was one moment, a half a century. It's a long time. Sure. Reflective. The second one came about 12, 13 years later when I'm in Coeur d'Alene, Idaho, at a brewmasters conclave.

with Anheuser-Busch and you got a stage, you got a U-shaped table array with in the middle on a raised podium, you got August Bush III, Gerhard Kramer, incredible chief operating officer for Anheuser-Busch and August Bush IV. And I gave a, I'm a yeast guy. That's how I became American, a chance interaction at Carlsberg during my postdoc days when

Made a genomic library of lager yeast and isolated genes related to diacetyl production. But I offered a job. So I ended up and I did a study, obviously yeast related. And there I am presenting my findings to that point in time. The only person that spoke first at these was Dead Silence, was obviously August the 3rd.

And he said to, turned to Gerhardt, he said, do you believe this, that kick now won't use profanity, that Casey's talking about? And Gerhardt said, for the first time and only time in my entire career, this statement, Casey speaks the truth. You know, I went, truth? You know, because truth is, you know, science is, you know, you always got to be challenging yourself. So that was, that was the moment.

And the next one was another, you know, like 10 years later at Testro when Morton Milegard, you know, the flavor wheel guy, the Dane. Sure. He developed that very shy individual, but incredibly brilliant just down the hall from me at Stroh. And I'll never forget him telling me in the hallway one day when practice and theory disagree, practice prevails. And that those three moments when I look back,

really kind of influenced my professional career very profoundly. Well, it is interesting to me. I mean, DMS, most of us are considering off-flavor, right? Something that we don't really want in the beer. But you believe DMS is actually an important attribute in lager beers, especially light American lagers. Why is that?

Well, like Charlie said, you know, it's all context specific. You know, DMS could be a good thing at a high level in a, you know, a German lager with 30 better in this unit. So they can have the flavor threshold can go up to 150. And, you know, it's, it's not that level of DMS and that,

that that brand is not a bad thing. And Charlie also mentioned Rolling Rock, which most, you know, in my tenure, we used as a training beer to taste what was with DMS Steak Slice because that's their brand design. They know it. They know they're getting that.

And they're fine with it. And that's what their consumers are fine about. Kind of like Corona was, you know, light struck in this skunky. I think they're, you know, they kill drinkability, but they're making their product to their design. So it's good quality. Yeah. They're clear bottles, right? But in the American light lager, you know, DMS is certain compounds that kill alcohol.

What August Bush described as drinkability, gentlemen, and which in Rocky Mountains, Rocky Mountain refreshment, there are certain things that certain attributes in the finished beer that kill those quality objectives.

And once DMS, like I said, it really masks the fruity notes of – you get a really good Coors Light, Bud Light. You get a little estuary, banana-y, strawberry-y. Not huge, but you get it. But you got DMS, it masks that, and it makes it, like I said earlier, kind of dusty. So it kills those. Dastil is another one.

I think the Japanese described it best when they described it as morning after sickness flavor, which if you think of it, it's puke on a bar floor the morning after. You get the ketone smell. Not a good one. You don't want it in a light lager, whereas in a Boston beer company –

You know, Sam Adams lager, you can actually have higher level to be in balance with the higher bidder. It's very common in English beers, for example. Yeah, in English beers. So everything's context-specific. Here we are talking about American light lager. And the other one is papery, you know, from oxidation. That kills drinkability, kills refreshing. Hmm.

Well, from a literature perspective, there's quite a bit of work been done on DMS. How and when is DMS formed during the brewing process? Well, for this one, you know, I'm going to, I always get mixed up with metaphors and analogies, but here we go. You know, and I'll try to invoke two,

Two perspectives, one a British and one an American. And British, you think of Monty Python. Now, for some, completely different. For the American, I refer to the Muppets. And if you think of the – if you're familiar with it, for younger listeners, take a look at Google. You'll see the old guys in the balconies, right? Yeah. Looking down.

And in this case, in terms of where DMS comes from, how it's made, what's relevant, think of the two guys that are there, but they're not in the same box, an adjacent box. One guy, and this Muppet actually looks kind of like a British guy who doesn't have a beer, Charlie, obviously. But he's looking at a stage where you've got a map of Europe.

And you've got, you know, you've got running around, you've got test tubes, you've got Erlenmeyer flasks, you've got two-liter EBC tubes, you've got pilot breweries. But the end product in all these worlds is not packaged beer. It's wherever far in the supply chain it goes there. And you've got that Muppet going, it's yeast. I told you, it's yeast. It's yeast. You go over to the other breweries.

where you got an old guy with great beer, kind of looks like me, and on the stage is a map of the United States of America. And through that has gone over my career roughly about 800 million barrels of beer, where the end product is the packaged beer is consumed by the public. And that guy, that Muppet, you know, he's going, it's not yeast. And I'm a yeast guy, right? There's certain iron in that. It's not yeast.

you know, if you want process control, focus on mold, focus on the brew house, focus on CO2 recovery, forget about yeast. You don't have to do anything to tweak that to get like 15 part per billion bud light, the lightest, um,

American Light Lager, in terms of DMS levels and finished package. So I'm going this way. I'm looking at a different stage, though, than the other. So I hope that becomes a little bit fun. I think Charlie will enjoy it. I hope he does. I think most of us would trace DMS back to malt, right? I mean, that's where the precursors come from anyways in the process, from what I understand. Yeah, there's two conflicting, again, with those balconies.

You know, the one on the European stage, DMSO, and yes, it comes from the malt. But yeast reduces it is the theory, and it produces DMS that goes into the packaged beer. The other balcony is saying, yeah, DMSO comes from malt, but it's irrelevant from process control perspective, whereas DMS...

DMSP also. So yeah, you've got, you know, I think if I'm not mistaken, something like Charlie's podcast, like 80% of DMS beer comes from the reduction by yeast of DMSO to DMS. Whereas again, the other balcony saying, yeah, we're all of it. Well, when did first, when did DMS first get on your radar screen? As you mentioned, you were a yeast guy. Well, you know, again,

It kind of got on my screen at stroke for the first time, being a Canadian by birth. Coming down to the United States, one of the things I learned very quickly as an applied brewing scientist is that us from the Commonwealth countries, including myself, really didn't have a clue in terms of process control for the drivers of drinkability and refreshment in the American light lager beer. So it was at stroke.

It came on my radar screen because the best mentor I ever had, malting and brewing science, was Joe Hertrick. Do you know Joe? I do not. No, I'm sorry. Yeah, Joe was the chief operating officer at Stroh. He's a very passionate individual when it comes to brewing and malting.

He did a master thesis almost when I first got there in 92 on, you know, brew house drivers of how the equipment and the various breweries in the Stroh system at the time were driving DMS package in finished beer. So that was kind of got on my screen. I'd never heard of it before. Although I did looking back, you know, the five, the four or five years at Anno's at Bush,

I was purely a yeast researcher. I didn't have any roles involved in DMS control, but I'll still look back. The wart stripper at the Anheuser-Busch breweries that was referenced in that earlier podcast, seeing the doors open and going, oh my God, you know, and seeing this stream, thin stream of a hot wart coming by, you know, sterilized air going up. And I thought it was like, you know,

Stanley Crute, uh, space 2001, whatever that oblique on the moon, right? I mean, what the hell is this? You know, I'd seen a few breweries in Saskatchewan, um, also, but I never seen anything like it, but there's a reason, uh, and as a Bush has some of the lowest and Budweiser, Bud Light, all their other brands, lowest TMS in their beers. Anyhow. Um, but then, you know, it, it really got on my screen was we started integrating. I was, uh,

responsible for corporate quality assurance at Stroke over those years. And we had training for DMS, you know, sensory training. And so we got familiar with it, both myself and the other panelists. Sure. And every once in a while, the other way it came up was everybody tests everybody else's beard, right?

You know, in St. Louis, they're tasting Coors, Miller, and all the others, and vice versa. It's part of your monitoring system for competitive beer analysis. And every once in a while, we're taking – a number of us got to the point, when we were tasting competitor light beers, we'd get to Coors Light, and we'd go, why is this so high in DMS? Whereas last week, or the months before, it was the best.

You know, it was the cleanest. It was just refreshing. Couldn't understand why DMS was, back then when I was at Stroh and Coors, was really not in process control. That was pretty self-evident. But then the first real practical experience came at Stroh. Longview, Texas. All places. That was an old slitsbury, right? And we finally figured out

You know, we got packaged beer. So we were doing analysis and, you know, there was a multi-plant system in Stroh at the time, 6-7, I forget what it was, especially with Heilman and Henry Weiner breweries that came online, but a spike in packaged beer in the Longview brewery. And to make a long story short, going into the process, and by this point, new enough to

you know, talk to the operators. That's the people you got to talk to. So you're sitting in, you know, the, the, the cafeteria at the brewery, just talking to the guys, Hey, anything going on relative that's different or not been done frequently that has been done recently. Pretty vague, right? One of the guys that he was actually, you know, there's an old rule that,

you should never really talk to the guy in the next urinal, right? But I couldn't help but say, hey, Bill Clinton's coming into town today in Longview. I was pretty excited. I was hoping, you know, I hadn't seen a U.S. president before and went looking straight ahead, of course. He goes, well, he

He might be your president, but he ain't my president. So this was, okay. This same guy later was the spark that they had done maintenance on the overboil detector in the kettles in Longview, Texas, and on inspection, and had been set slightly lower than

than it had according to what it should have been specs of what it was before. So what's it do? That's off the boil. So you're not sooner. There's more. Oh, so you're not getting this, not getting as a complete a boil, right? And that obviously the boil is a big factor. Yeah. Yeah. That finds itself as a single cell. Um, I've got like, I don't know, 30, 40 fish bones on DMS control. Um, it's one cell, but to me it was on you, Texas. Um,

Just things like that. But that's when it first got on my radar. And I mean, is that how you go through identifying a cause for DMS in your process control? What's the best way?

Well, you know, DMS was a huge, really a huge learning curve for me as an applied room scientist and the teams that I work with. And it boiled down to, okay, when you're trying to investigate the end of the supply chains, obviously the beer, right? The finished beer. That's what the consumer tastes.

was the principle of doing process surveys. Never assume paradigm, right? Never assume what pundits might say, this is where it happens, and you focus in on that.

Because DMS taught me two really important, you know, how to study it in, you know, in breweries that are making millions of barrels of beer a year. Well, you got to do, you know, you got to do process survey. You got to, your measurement, you always have to challenge your measurement at the time. How is it that you're measuring it? Because there's two, every variability, every measure and every value has two sources of variability. I'm kind of wearing my...

ASBC president tech committee had, but it's the measurement itself. Right. The gauge, the gauge, the gauge is your gauge actually measuring what's truly in process. And then the other variability variable is the process itself, how it's being operated. So you got two components in a measurement gauge and process, and you have to be damn sure your gauge is telling you what's really going on.

And we didn't. We first started, ironically, I remember back, you know, looking at some of the early papers from the United Kingdom on DMSO to DMS and, you know, the whole DMS story, realizing that, you know, the gauge that was being used at that time, which was a purge and trap, you know,

And then measuring that was not at all reflective of what was actually in process in these thousand barrel birds, barrel fermenters, right? And what it was, the best, really, the most amazing brewing chemist I ever worked with was Lawrence Denbigh at Stroke. And he developed what became now the global way to measure DMS in process.

And it was headspace, chemiluminescence, sulfur-detects, chemiluminescence. And that, boom. Once we had the measurement, you know, when I got to a brewery and next brewery, I arrived there in 99, 2000. And the paradigm is, because I knew that.

From that stroke experience, something was going on with, you know, in terms of DMS control. And the dogma of the paradigm was, oh, it's 100% yeast. And I'm like, really? Okay. How do you measure it?

And it was the previous measure. So Lawrence Stenroos, 2002, he flew out to Colorado to visit us and to walk the lab through the method that he, you know, when you look at, you

This poppy here? Yeah. Methods of analysis. Google Lawrence Stenruths, and you'll find 34 hits of him on the ASPC site. But he developed a method. He taught the lab at the time, and he said this is how, you know, this is now the ASPC method. Sure. We went into the process, and lo and behold, it was not zero going out of the brew house. It was about 100 part per billion, dropped down to about 90-ish percent.

And by the end, and then by the time the beer was finished, it was down 45-50. But it completely changed the paradigm, right? The gauge. The gauge was telling us pre-2002 was all East. And post, it was like, oh, wow, we didn't get any more formed in, you know,

We were able to control it. Then we went into process DMSB, and it was really gratifying to see from process capability perspectives to see the DMS come in control, come down with all the major brands. And it was just cool. I mean, it was just a great moment.

professionally relative to applied science to be able to say, this is what's driving it. Did the survey. Let's see if we get this under control, multi part and take it from there and boiling, especially 6,000 feet. Right. And I'm like, you know, having those conversations. If you heard a DMS to the floor, the brew house operator, no, but starting education, what is DMS? How does it relate to all those things? So,

A little long-winded there, Brad, but I'll leave it at that. That's okay. So how do you actually go about approaching a problem? Like, let's say you have a problem with DMS or some other problem, but, I mean, do you go back kind of like you would root cause analysis and do like a fishbone tree and try to identify all the causes? Because something like DMS, you know, potentially goes all the way back to the maltster, you know, in terms of cause. There's a lot of potential off-ramps there for what could be the root cause. Great point. Good.

Because that, you know, the process survey, which I mentioned earlier, that wasn't how Greg Casey, as a young scientist, entered, you know, how to troubleshoot loss of process control for critical beer attribute. It just wasn't on my radar screen. But the Stroh years did. And again...

Not to beat dead horse, but you got to have the gauge that you know is telling you what's truly in the process so that you can assess variables in that process. But you also have to take a don't focus in, dial in on one area and assume that's the area.

First thing you got to do once you got the gauge control is do a complete process survey from raw materials in the packaged beer and measure in those value-added points the attribute that you're interested in. And that proved pivotal relative to DMS control once we had that gauge, but also proved pivotal other examples. And I'll just, you know, things like 4VG and 4 vinyl...

4-VG and 4-VP, vinyl phenol. These are, you know, like the hams, you know, the spicy taste you get in ham of these, you know, these compounds. The dogma is it's wild yeast. The wild yeast makes these in...

from contaminated yeast. And when you're the guy who supplies the brewery with monthly shipments of yeast, you got a rather agitated chief operating officer going, you're sending us bad yeast. I said, hold on, hold on. Let's just do that survey, right? And we did, and long story short, three times flavor threshold in hot wort carried right through. So this thing was loaded with it.

even before it saw yeast. So, you know, we did that time and time again, the teams I was blessed to be part of, where we do a process survey, you know, one, you know, in terms of flavor stability, in terms of if your paradigm is you got to keep it cold, shipping throughout the entire supply chain and the costs associated with that. How do we go back in the process, building credits to enable, once it leaves the brewery, to be like standard shipping, not refrigerate?

And again, I look back on the teams and my goodness, the learnings we had, the applications we had. And again, it's all in that stage of, you know, for Stroh and Coors, that was probably about, I don't know, 300 to 400 million barrels of beer that we

That was our world. That's what we were trying to get process control on and did get process control. Yeah, I mean, I used to build satellites and missiles and things like that, and we'd have the same thing. I mean, some of them would fail on orbit. You'd go down root cause, try and figure out, you'd build these giant fishbone trees, try and figure out what was wrong. Yeah, I got my son says definitely in college.

confirmation of obsessive-compulsive disorder in his father. It's not like 3,000 of those fish bones. Yeah.

because I'm running out of binders for the other obsession I have, which is that telling the American people the story of our history when it comes to our national beer, our national beverage, and the world's most popular style of beer, adjunct lager beer. You know, 16,000 references on that. So, yeah. Interesting. Like Charlie said, you know, in case you're fucking any younger, right? Yeah. Where the hell did this come from?

And you become, as friends start dying around you, you become definitely younger than you and very suddenly you blast off with other things. You look at life a little bit more reflectively. And that's a good thing to, you know, to think about that. Sure, sure, sure. Family legacies, all that. So what are some of the things you learned working on DMS?

Well, I learned if, you know, again, if this whole, I hope this is just geared, my audience I'm trying to reach here, Brad, is people that are starting in the industry now and people that are fairly early in their tenure with a brewery of any size. When it comes to DMS, you know, where are the process control points that, from my perspective, you need to be considering? And again, am I speaking the truth or not?

That's for you to judge, just like our beer, you know, in terms of I'll let the public decide. I'll let those that listen to this decide for themselves. But there's three really critical control points. One, DMSB specifications involved.

that's crucial, especially for an American light lager. Because those are the precursors, right? That come from the malts. Yeah. So that's, you know, barley and malt spec, but it's the malting operations. How do you drive it up and down? How do you, what are you trying to deliver to the next value added step, which is the, you know, brewing process. So you can set DMSP specifications. And again,

over two years in terms of statistical process control to see your process shift when you do certain things to the process. The result is it's pretty heady stuff as an applied scientist. Same thing with CO2 reduction.

that's the second big bucket I recommend you look at if you're redoing it, you know, in terms of, I got, there's a lot of learnings on that one in terms of Wittenman systems, in terms of maintenance, in terms of, you know, iodine checks, carbon regeneration, water flow, number of spray heads, all those little cells on a fishbone relate to a real learning in straw or later. So that's number two. And,

And the third one is your brew house. That's a biggie, you know, in terms of how you operate. I already used a long new example, but that's only one variable. My goodness. Yeah.

I'm looking over there at some of the collection of fish bones specific to DMS. And there's like three pages just filled with red cells, which was a practical learning that was applied and resolved the loss of process control issue. So those are the, you know, DMSO is the other one that's both, you know, yeast reduces it.

in fermentation to DMS, which is the other balcony. But that's a world I never saw as being relevant in terms of keeping owners of Peter Stroh and Bill, Pete, Pete Jr. Coors, keeping them happy with their product being refreshing to the degree DMS is one of the attributes that drives it. There's others.

An interesting question, though. So you mentioned DMS is important in the beer. You obviously want some level of DMS, right? It's not something you try and completely eliminate. You know, it's a good question, Brad. I don't know if you, you know, again, it's Matrix. I described beer as Matrix, but brand specific.

specifications you know so you have a spec charlie talked about uh carling uh black label i believe and um scotland and england and you know uh interactions of other components so each brand has you dial in your specs you try to control your process to deliver those and the easiest thing to do quite frankly is to drive up dms shit that's hard to

that's the easiest thing to do because all these other control points, particularly in Bruin, you can very easily. But in the American light lager, you know, you got Bud Light, as I mentioned earlier, the lowest, I think it's like 15 part per billion in terms of DMS. That's the best. I don't know what their specification is now. It's been a long time since I worked there, but I would imagine they're somewhere in that, you know, 15 to 25 part per billion that they're trying to deliver. Not necessarily because it's,

uh positively contributing to flavor profile in terms of drinkability but because if it gets any higher than that it starts impacting drinkability so you know dms is a highly brand specific you know and i've defined quality the beer is delivering to the consumer consistently what your brand design specs are whether they're the right specs another thing altogether but

Assuming they are, yeah, if you can deliver and the consumer says, yeah, that's a beer I'm going to buy, that's a quality beer regardless if it's 150 part per billion in a German all malt 30, you know, BU beer or Bud Light was not that many BU's but very, very little DMS. Now in the notes you sent me, you talked about quality at the source and specific quality objectives. Can you talk a little bit about what that is and how that applies here?

Yeah, that's, you know, again, and again, it's something that kind of overlaps with, you know, process survey approach, you know, where you go into the process and you're talking not to people in the lab, you're not talking to fellow brewing scientists, you're talking to people that are athletes.

part of the process. Sure. And, you know, to internalize and to develop over time, and it takes time, you know, a quality system links to that individual's role, whether they're in an enabling process like procurement for materials, whether they're in engineering department or maintenance department, the people, people in the brew house, the people, you know, everywhere across the supply chain, you talk to them about, this is why DMS exists.

Just other things, too. But DMS matters. Here's how your process, here's how you're adding value or adding value to what your input to your process was. Here's how you influence it. Get them talking about, oh, DMS. And one of the more gratifying things is, you know, quality assurance, corporate QA days, of course, is when an operator starts talking about DMS.

DMS or paper, you know, you hear them using those terms that you knew several years prior wasn't something that was being mentioned, that you can distill that down. This is how you influence quality at the source for the quality objectives, you know, for particularly the attributes I described, which is American light lager or drinkability and Rocky Mountain refreshment. What the hell does that mean in terms of what you do? And you build a

a quality system around that that has to cut across the whole supply chain because if it's lost at any one point,

your hopes, you know, once you pass on your screw sort of thing. So it was pretty, again, it was, those were heavy days. Again, you know, looking back at the team members, you know, we had growing chemists, we had growing sensory scientists. We've had a few engineers in there. We had a whole slew, but we had to get into the source and talk to them and measure. Again, it comes back to that. Once you got a gauge, you could tell it's really going on at each part of these processes.

Now, you've mentioned Dr. Charlie Bamforth a number of times, and I will link in the episode I did with him on DMS, which goes into a lot of detail on the chemistry behind it. But you said that you have a different perspective on DMS than he does. Can you tell us how you differ? Charlie, you're listening to this. I hope you are, because I love listening to yours. Charlie and I, again, I use that metaphor analogy, where the hell it is, the two balconies.

Charlie, if I could distill it down, I would say his perspective is DMSO, induction by yeast in fermentation is the, I think he said something like 80% or whatever of the

dms and final beer sure in case i say dmso i never studied it over those 800 million barrels of beer not once um we definitely did once we got the gauge down going to the process and i my experience again telling the truth or just what i think i know now i refer to the young people challenge every one of us you know myself and charlie but i say no it

We got process control with deliberate actions to influence the process in terms of where those critical control points were. It had nothing to do with yeast. So we have two, you know, two very different. So you feel it's much more on the malting and boiling side, I guess? Yeah, it's a hundred, you know, in terms of, you know, how the heck does, you know, does Anheuser-Busch get down to 15 billion DMS?

you know without focusing on malting without focusing on brew house without focusing on co2 control you can't get there without doing those things but can i read one cell yeah go ahead and then and i think this kind of because one of the things charlie talked about i agree totally um in terms of the chemistry reducing right remember that brad he was talking about oh yeah yeah and

And I don't remember what the exact reference was, but I put it in one of my cells where Charlie was talking about bottled conditioned beer. So you're putting, you know, our son makes bottled conditioned farmhouse ales, but, you know, bottled conditioned beers, you add a little fermentable sugar, you add yeast, you crown it, cork it, you make it a closed ecosystem, right? So that is, you got yeast, living yeast, and fermentable sugars in a closed system.

And reducing power, and I'm going to use an, I guess this is an analogy. I'm not sure again. I've got to figure this out.

probably not. Um, you know, is that, uh, reducing power to me once, you know, I got to this level of gut level, reducing power from the yeast perspective is stripping off hydrogen off medical fermentable sugars, right? You're stepping them off and it's all part of their generating energy and they got to dump these hydrogens to be able to continue generating, you know, so DMSO, do I think, uh, yeast can reduce DMSO, um,

in a test tube or an Erlenmeyer flask or BBC tube or whatever. Hell yes, but I think they're desperate to that reducing power to regenerate. They'll reduce a lot of other compounds in that non-operating process if you stuff it with that and you say, hey, I'm getting not just TMO, but these other oprah. I haven't done it, but it is an analogy. But in bottle-conditioned beer, if you think of it,

bottle-conditioned beer, the yeast or the fermentable sugar, that reducing power, they're desperate. You know, they got to... Sure. You know, they should be reducing... Anything they can find, yeah. ...the yin-yang, if that's the case, but...

I forget which brand he said, but the study was looking at DMS in that packaged beer started 20 degrees over six months. So you got a closed ecosystem. Charlie writes, indicating in the yeast, the DMS stayed constant throughout the entire time. And Charlie said, indicating yeast is...

capable of producing DMS, just that it's not detectable under the prevailing conditions in the bottle. Interesting. So, you know, that's the kind of stuff. I have my paradigms. I'm 100% guilty. You know, I believe strongly in certain things, but, you know, in the first volume, you know, there's a guy by the name of Dr. Martin Stack who indicated that the use of adjuncts was greedy brewers' fault.

That were shippers, not the local. And I sort of went, no, I went back and said, we all have our, you know, our paradigms that we just have blinders on.

That to me, you know, is a good example of that from a yeast perspective, because there's a lot more DMSO, right? Charlie mentioned about so much of the DMSO carry through, uh, that is not reduced, uh, to give the package TMS, but it doesn't, you don't see any development, a closed ecosystem where yeast is. Yeah, I understand. I understand what you're talking about. You know, I've got 34, whatever his number of fish bones, they're one cell. Um,

I might, you know, maybe afterwards we could talk. Brad, I maybe give you these, clean them up, many of the fish bones, because like I said, I'm going to be throwing these up soon to focus solely on the books, history. But maybe you can put them up to a link or something. Interesting.

Well, thanks for coming on the show. I did, before I close, I want to mention your five-volume set again. Where can folks find it? If you go to the Master Brew MBA, Google MBA, Master Brew Associations of America, there's a link to publications there that you can order directly. I was blessed. We raised about $40,000 to try to keep production costs down for people in the industry. Oh, nice.

Reference there, Ken Grossman and Dick Yangling wrote incredible forwards to give the perspectives of craft and sixth generation American adjunct lager beer. And it's really exciting. So it's expensive, obviously, because I think it's something like 105 bucks or something along those lines. Like a textbook. Yeah, but it would have been double that price if these folks hadn't stepped up. So I'm really excited about that.

And again, you know, it's kind of like this is an ultimate process survey again, you know, in terms of challenging paradise. Yeah. You know, but anyhow, like I mentioned earlier, like the beer.

People read it, make up your mind. Am I full of SH, you know what? Or is, you know, listening to the voices, because that's what I really emphasize is the people, not the science, not the gory details, not the statistics, but what people of the era were talking about relative to our national beverage.

Well, thank you, Greg. I appreciate it. I want to get your closing thoughts quickly. You know, I go back, you know, in terms of to that reflective and, you know, my journey started as an applied scientist roughly 50 years ago, if you will, with that lecture in Guelph, University of Guelph. This is what we think. And, you know, it carried through when I look back.

virtually everything that I've, you know, enjoyed during that period of time in my life. You know, from the PhD, high-gravity brewing, that yeast, you know, the paradigm was yeast, brewer's yeast have low tolerance compared to wines and distilleries. Well, horse crap. You know, four or five years later, we demonstrated you could ferment 25 plate awards to end the fermentation. You get...

some pretty high levels of alcohol if you had the right nutritional mix. So that challenged that. Then going to Carlsberg, those two years, the paradigm in the early 80s was laundry yeast were so stable because they were polyploid. They had 3K,

had three, four, five sets every chromosome. So from a perspective of inducing mutations, yes. But what the mentoring taught me at Carlsberg was, oh no, these suckers, you know, in terms of chromosome profiles, they can adapt and change the mix of chromosomes. We get like a UPC code at the grocery store, very different yeast, and you could direct that.

By putting on a selection pressure on that population. So that was kind of interesting. And then all these examples I mentioned earlier, going into resolution, how do you approach troubleshooting as an applied scientist when your world, your stage, if you will, is hundreds of millions of finished beer barrels, that is.

Losing my voice. I think that's probably, you know, good place to finish. But again, I want to be really specific here. Charlie is, you know, to most of your listeners, who the hell am I? I get that. That's fine. Charlie's a, he's done amazing things over his career. Yeah. He's a national treasure. There's no doubt. He's a national treasure, you know, as an author, as a spokesperson for the industry. He taught my son, uh,

At University, you know, UC Davis. Yeah, UC Davis. You know, he's, you know, he's, he's incredible. But, you know, his world was that stage. I talked about my world was very different. And I just felt, well, let's give.

As I get to the point, if I'm dead tomorrow, at least young brewers. It's good to have different perspectives, but yeah. So that's all it is. But I admire the hell, Charlie. We share beers together. I look forward to seeing him. He's so entertaining. He's so, God, he can remember things that I forget all the time. Yeah, he's a good guy. You know, different stages. Well, thank you, Greg. Really appreciate you coming on the show today and taking time to join us again.

Yeah, I appreciate it. Yeah, thanks for having me back, Brad. Maybe sometime this time next year for the books, I hope. Well, good, Greg. We'll definitely have you on again next year. We can talk some more about that project and how it went. And hopefully you probably have your third volume almost done by then, so it'll be good. Yeah, well, it probably won't. They'll be coming on a yearly basis, but it'll be early 2026. Third volume will come out. Sure, sure, sure. And then each of the subsequent Q1s in the next two years.

Well, thank you, Greg. Today, my guest, Dr. Greg Casey, who worked at many of the largest breweries in the country, also chair of the education committee at the Masters Brewers Association, former president of the American Society of Brewing Chemists. Dr. Greg Casey, thank you once again. Thank you. Appreciate it. Always fun.

Well, a big thank you to Dr. Greg Casey for joining me this week. Thanks also to Craft Beer and Brewing Magazine. They recently added a new collection of more than 500 beer recipes from pro brewers to their site. And most of them let you download the Beersmith recipe file. The new Craft Beer and Brewing recipe site is at beerandbrewing.com slash beer dash recipes. Again, that's beerandbrewing.com slash beer dash recipes.

And Beersmith Web, the online version of Beersmith Brewing Software. Beersmith for the Web lets you design great beer recipes from any browser, including your tablet or phone. Edit recipes on the go with access to the same full suite of recipe building tools as our desktop version. Try Beersmith Web today by creating a free account at beersmithrecipes.com.

And finally, a reminder to click that like and subscribe button on YouTube, iTunes, Spotify, or whatever platform you're listening on. Clicking those buttons is a great way to support the show. I'd like to thank you for listening, and I hope you have a great brewing week.