Dr. Michael Crowder is a Professor of Chemistry and Biochemistry and Dean of the Graduate School at Miami University. Dr. Crowder's research interests lie in bioinorganic chemistry, including metalloenzymes, antibiotic resistance, metal ion homeostasis and inhibitor design.
Episode Description
By the end of 2023 Bourbon is expected to be an almost 9 billion dollar industry. That’s a lot of mint julips and bourbons neat. But what makes bourbon so appealing, the chemistry behind this drink is the focus of this episode of Stats+Stories with guest Michael Crowder.
+Full Transcript
Rosemary Pennington
By the end of 2023, Bourbon is expected to be an almost $9 billion industry. That's a lot of mint juleps and bourbons. Neat. But what makes bourbon so appealing? The chemistry behind this American spirit is the focus of this episode of Stats and Stories, where we explore the statistics minus stories and the stories behind the statistics. I'm Rosemary Pennington. Stats and Stories is a production of Miami University's Department of Statistics and Media, Journalism and Film as well as the American Statistical Association. Joining me is regular panelist John Bailer, emeritus professor of statistics at Miami University. Our guest today is Michael Crowder. Crowder is a professor of chemistry and Dean of the Graduate School at Miami University, Crowder’s research interests lie in bio inorganic chemistry. And he's also really into the science behind bourbon. Mike, thank you so much for joining us today.
Michael Crowder Thank you, Rosemary.
Rosemary Pennington I love bourbon as one of my favorite, you know, alcoholic drinks. And I wonder, how did you come to this interest in bourbon?
Michael Crowder Well, so when I was a kid, I was very fortunate to live in a town where a lot of my extended family lived right there in the town. And every Thanksgiving and Christmas, our families would come together. And these were pretty impressive things. The men had to wear a coat and tie, including the boys, oh boy. And the women would wear dresses, and everybody would bring food. And it was time to just sit back and enjoy each other's company. I remember vividly that the men would often retire to one of the front rooms. And in those front rooms, there would be bourbon flowing. And it was usually Virginia gentlemen, in early times, which I look back on now and say, Wow, we could have done a little. But they wouldn't be in there. There was some cigarette smoking going on. But they would be drinking bourbon and discussing exactly the topics that you shouldn't be discussing with family, religion and politics. And I remember as a boy, I was always kind of terrified, because there will be voices raised and everything. But I couldn't wait to be invited to go and be with the men. And when we were probably, I have a twin brother and a cousin that's the same age, and we were probably invited when we were 13 or 14 years old. And they gave us a little glass and they waved the bourbon over and put some ginger ale and ice in it. And we felt very special. None of us said a word the first couple of years. And then they got to the point where they couldn't shut any of us up. But I look back on that as one of my favorite times. And it was around bourbon. It was about fellowship. And it was about enjoying each other's company. And so I look back very fondly on that. And then if you go ahead forward into the future a little bit. When my father was passing away from cancer, I would drive to Virginia every weekend. So that's about a 10 and a half hour drive each way. And I would pour him a bourbon, and we would sit down and just discuss things. And so those two things, it was around fellowship and enjoying each other's company, is really where my love of bourbon started. And so I knew I was destined at some point to maybe do research on it. It would just take a few years. Yeah.
John Bailer
Yeah. So I'm sitting here picturing you holding a glass of bourbon. And so I'm saying, you know, Mike, what are you doing? And you said, I'm doing research.
Michael Crowder
That's exactly right. And actually, I've gotten to where I really appreciate the time I take, and I say I know that oh, the palette of every bourbon is different. And I found that even my mood and what I did that day and what I ate that day will change the way that I actually experience bourbon. And I always start out neat with it, and then always add ice to it to see if the bourbon can hold up to the ice, and not all of them can.
John Bailer
So what is a bourbon?
Michael Crowder
Yes, so bourbon is an American spirit. It is the distinctive American spirit. It is a whiskey. And so all bourbons are whiskies but not all whiskies are bourbons. Bourbon has a very strict definition associated with it as defined by law. It needs to be made from at least 51% corn, and the recipe for bourbon, for any distilled spirit, is called its mash bill. So it must have 51% corn and then almost all bourbons have some percent, maybe 10% malted barley. And there's science reasons for having malted barley. And then the flavoring grain can either be wheat or rye. And all those have to, of course, add up to 100%. A second very important part of bourbon is that when it is distilled, it can only be distilled to 160 proof or less. And so the reason for that is, is that at 160 proof, there are still other chemicals called congeners that are in the bourbon. And they actually add to the flavor of bourbon. When the distilled spirit is put into a barrel, it must be at 125 proof or less. And then when it's bottled, it needs to be at least 80 proof or higher. And so there's a bunch of different distinguishing parts of bourbon and you have to follow those laws in order to be able to call your product a bourbon. One thing that most people believe is that they believe the law says that it must be aged in a barrel. And that is not the way the law is written. What it says is it has to go into an unused, charred oak container. It never uses the word barrel. And another thing that many people don't realize is that they think that bourbon must be made in Kentucky. And 95% of the world's bourbon is made in Kentucky. But it has to be made in the United States or in United States territory to be called a bourbon.
Rosemary Pennington
So what gives bourbon its flavor? I love whiskey, just generally very broadly. But I'm not a huge fan of scotch. It's one of the whiskies that I just can't get into. And people are always kind of surprised about that because I like bourbon. Well, I like whiskey generally, what gives bourbon its flavor? How do whiskies sort of get their flavor? And what is it about bourbon that is so special?
Michael Crowder
Yeah, so I'm not a huge fan of scotch either. And right, I'm sorry, John. But the reason is that very often scotch, first of all, there is no corn, and scotch, it has to be malted barley, and some of the most famous scotches in order to dry the malted barley, they use peat and would heat the peat and use that to drive out the water. So it wouldn't continue to do its chemistry inside those seeds. And that imparts a flavor on it. And that chemical, we actually can detect that chemical. It's called phenol ethanol. And it has the flavor of band-aid adhesive, also should be in marketing. Yeah, that's usually not a very good thing. But there's that same chemical in bourbon too. And then also in scotch there, it stays in barrels much longer than most bourbon suits, typically. And so there's a lot more of those flavors coming out, too. And there's a whole range of chemicals that you can detect in scotch as well, they're in there in bourbon too, but not as high as levels as you do in scotch. With bourbon, one of the things that always people get is that sweetness, and that's coming from the corn. And corn is very important for the flavor profile of bourbon. You also, though, from the barrel aging, you have pulled chemicals out of that barrel. And, and then also remember, we only distilled to 160 proof or less. So there's other chemicals that yeast makes during fermentation. And those chemicals are there. But that's still not even the full story. Inside that barrel, there is all sorts of chemistry going on with oxygen. So the distillate in that barrel will actually evaporate out of the barrel over time. And when that does, oxygen comes in, and oxygen gets activated. We don't know the chemistry behind it, but it will react with those compounds from the wood and then from the yeast to make new compounds. Many of them are flavor compounds. And that's what you really love: things that are in there that have green apple taste, and they're things with banana taste in it that are actually some of them are made by yeast, but some of them were made in the barrel.
John Bailer
So I read in some of the background that we had looked at that something like 70% of bourbons final flavors are from the interactions with the where they're stored in the barrel?
Michael Crowder
The barrel actually introduces, most people would argue, about 70% of the flavor. And so a good thing for you to try is that occasionally, you can find it at the store, there are things called white dog that you can find. And so that is a distillate that never touched a barrel. And so you should actually do a little experiment and taste that and then taste an age barrel. What you're tasting? The difference is what came out of the barrel and the chemistry that occurred in the barrel. Yeah, so it's awesome. It's very complicated, too.
Rosemary Pennington
When I was working in public radio, one of my favorite stories was about home brewing in Alabama, because in Alabama, you could not sell high alcohol beers. And so you could brew them yourself. And so I used to hang out in this brew store for like, a whole day with these guys who were brewing beer. And one of the people was a theoretical chemist. And he told me the only real chemistry he ever did was when he was brewing his beer. And so I wonder what exactly, when you are studying bourbon and looking at it, what are you looking at? How are you studying this spirit besides sort of smelling it and tasting it?
Michael Crowder
Yeah. And so and that's an excellent point. And I will tell you that at these big distilleries, they have blenders and master distillers who can taste and smell chemicals at levels that there is no instrumentation that can detect it at that level. They have trained their palates there and their nose is to be able to detect things that are just unbelievable. And so a lot of the bourbon science was very, it's a lot of art to it. At one time, it was making the right choices, which barrels needed to be combined with other ones. And there was such an opening of, well, what's the science that's going on here? Why is that in some cases, barrels that are put in a brick house, they go up in proof over time, and other ones go down? And proof over time? What's happening there? And if you go on Bourbon Trail trips, they will invariably tell you that wrong, they'll say, Oh, the proof always goes up in a barrel. That's not true at all. It depends on the barrel. And it depends on where it is in the brick house. And so when I used to take a group of Miami students down to Moonshine University in Louisville, we taught a fermentation class. So it was Luis Actus, Chair of microbiology. Tom, Chris started that with us. And then we had faculty from chemical engineering, from chemistry, psychology, biology, microbiology, and we would teach this fermentation class each year in the fall. And it was 6pm to 9pm on Wednesdays, because we did field trips. We would go to breweries, and work with the head brewers. And then we even went to some distilleries while we were doing this class. And at the end of that fall semester in winter term, one of Miami's alums Dave Defoe owns Flavor Man down in Louisville, and he opened up his own distillery and learning center called Moonshine University. And the general public can go to this and where you can actually learn how to do distillation over for a four or five day period. And Dave actually gave the tuition to the Miami students that went and you know, they bring in expert people in the bourbon industry, and they come in and teach you how to distill. There were people from legal that would come in and talk about the legal aspects of distilled spirits. Marketing is huge, particularly in vodka. Vodka is vodka, and it's ethanol and water and just a tiny little bit of other stuff. And so how do you make yours distinctive? And so I would sit in every year that we went, and I would listen to these people. And I was thinking to myself, you know, why does that bourbon taste different? And so we actually, after several years, brought a sample back to Oxford. And we went to Ohio State, they have this enormous piece of equipment. And with all equipment, it's always a bunch of abbreviations. And it's called an F T ICR. Mass Spec. So it's an enormous instrument, about a $15 million instrument. And it can detect chemicals at tiny amounts, parts per billion amounts. And we took white dog and put it into the FDA. And they looked at us like we were crazy. They were really excited that we had come and the white dog, remember, when you do distillation, you're purifying a beer, that's essentially what you're doing. When you homebrew, you make a product that looks identical to what they put on the distillation column. And so you have purified this beer. And yet we could detect at least 10,000 chemicals in a white dog. And so imagine how many you can detect when you put bourbon in there. And we could see, we don't know, even a small fraction of what those chemicals are. But what it turns out is different bourbons have different amounts of these different chemical holes in them. And that's what distinguishes one bourbon from another.
Rosemary Pennington
You're listening to Stats and Stories. And today we're talking with Miami University's Mike Crowder about what makes bourbon so good. So that's my opinion. Like it's not a verifiable fact. I have done bourbon distillery tours and the thing that the stills are always so incredible to me. But so many of them are copper or have some amount of copper in them. Why is copper important to this process?
Michael Crowder
Yeah, so copper is essential. So one of the big reasons is are those big tall stills that you say they're called coffee stills, and they were actually invented for scotch. Yeah. And then they were kind of adopted and or stolen by the industry. However, we want to say that borrowed perhaps that's right. Copper is a great metal for a couple of reasons. One is that you can hammer it into different shapes. And so that was very big. It's also a great conductor of heat. And so you could heat these copper kettles up if the heat moves in and out of your solution or whatever it is that you're trying to heat pretty easily. But it turns out, it has a chemical essential part of it too. And that is, when yeast does its biochemistry, when it's making alcohol for us during fermentation, it makes hundreds, maybe 1000s of other chemicals. And one class of those chemicals have the element sulfur in them. And so we all have experienced some of the sulfur compounds like when you walk by where skunk is man, that's a sulfur compound. But the sulfur compounds, we can detect tiny levels, that's why we ended up putting them in natural gas. So if we smelled that, that sulfur containing compound, we know get out of there. Well, the yeast produces these compounds too. And if they made their way into your glass of bourbon, it might not be a very nice experience. And so what happens is that the sulfur containing compounds react with the copper. And what happens is that the copper changes, it loses electrons and the sulfur then the smell of it actually goes down. And the copper then is released into your distillate. And so over time, the inside of those still start to pit. And they have to be sometimes resurfaced or new copper put in them. And I think that copper is actually very, very important for something that occurs in that barrel too, although we haven't proven it yet. It's a hypothesis I have. I mentioned earlier that oxygen comes in that barrel and the chemicals inside the barrel react with each other. And it's through oxygen chemistry. But oxygen does not react very well with compounds that have carbon in them, like a lot of the compounds in that barrel. You need something to catalyze that reaction. And I suspect that copper is a major player in this. Because in biology, copper reacts with oxygen in lots of different biological systems. I suspect it's playing a part inside that maturing and aging in the barrel as well.
John Bailer
So Mike, as I'm thinking about your description of all this, I'm picturing kind of this flow of the inputs, the outputs, and then the user experience with the bourbon. And so from the inputs. I've heard you talk about the idea of the corn and the amount of corn or maybe where the corn is sourced from yes, there's the malted barley, the flavor grain, but also there's the water and then the nature of what kind of water you're putting in which certainly the scotch, yes, producers think a lot about that as well. But then there's also storage, then there's also humidity, there's also conditions of storage. So you have all of these inputs. And then I've also heard you now talk about 10,000 plus different chemical chemicals that can be measured in the bourbon. And then there's the taste, yes, the user experience with this. So as you know, given the Stats and Stories gig we're doing here, yeah, you know, what's this process of thinking about these chemicals? How do you? What are some of the things that you've done when you've looked at kind of inputs related to outputs, or how you've used outputs to explore a comparison of the different bourbons?
Michael Crowder
Yeah, well, so this is something that has really not been done very much. I did find just in the last two weeks, some papers that are never really referenced that were in these studies were done in the 1940s. And so we've just come off a prohibition. And the company that didn't that ended up owing what we now know is Buffalo Trace, did a large study where they looked at hundreds of barrels where they put new distillate into those barrels, and they were making chemical measurements over time, and those from the individual barrels. Now, they didn't have the analytical equipment that we have now. But they were looking at things like, did the acidity go up in those barrels? And they do go up quite quickly. And that could also be aware that she catalyzed those reactions in the barrel too. And there were a whole bunch of other things that they measured as well. And then it was like, crickets, there's really not much done, if you fast forward. And I would say that some of the distilleries are doing it, but I would bet most of their research is tucked away somewhere and it's proprietary. But Buffalo Trace back in about, I'm gonna say about 15 years ago, believe it or not, bourbon was not very popular then. And they were the bourbon industry was struggling. This is the 80s, and even a little bit into the 90s. And, you know, they were struggling, their market share was going, vodka was winning out, wine coolers were beginning to come in. It was a whole bunch of other options. And there was a lot of fear in the bourbon industry. In fact, the whole reason that Blanton's ever came forward was because the distiller there was told you need to come up with a new product. And he said, Let's try the single barrel. And it was a big gamble. Oh, and the single barrel then turns out to be a very, very popular type of bourbon. And so they had a lot of capacity on their lines at that point. So they started this project called the Single Oak Project. And it was, and you can read about it on the Buffalo Trace website, but what they were really after, and it was something that you didn't list, but it's a huge variable in bourbon, or the trees. Yeah. And so depending on where the tree lives, what things it pulls out of the soil, how tight, how close the rings are, there's all these different, you know, permutations that can affect that bourbon at the end. And what they ended up doing was they did a set of experiments, they harvested almost all of their white oak from the Ozarks. And this is all described on that webpage. And then what they did was that they used two different recipe arrays and a wheat mash. They put the bourbon in at I think 125 proof and 105 proof or so it was a different proof. They put them in two different types of brick houses. One that was very much like the Blanton's one that has the old metal and another one in a concrete one. And it turned out to be 192 different barrels. And what they did was aged it eight years, and then they bottled them. And at a time, you can actually go and buy them secondhand or on the secondary market now, 375 ml bottles of single oak specific barrels, and they let a group of tasters taste them. And it turns out for whatever reason the tasters preferred barrel number 80. So they know the recipe for that. And so they actually have barrels at 10s of 1000s of those barrels aging right now. And they're going to release those in 24-25.
John Bailer
Oh, wow. So Mike, one story that you told me kind of in a different context was an analysis that led to a surprise. Yeah. And I was wondering if you could share that story with us.
Michael Crowder
Yeah. So when we started doing our analysis of bourbon, when I saw 10,000 compounds and knew that there was no way we were going to be able to figure out what all of those were, I said, we need to go to a technique that's less sensitive. So over in the chemistry department, here at Miami, we have tons of instruments called nuclear magnetic resonance instruments. It's like an MRI when you go except for instead of putting a person in the magnet, we put little vials of bourbon. And with those, we could actually detect and actually determine the concentrations of 17 chemicals. And I said, that's a more manageable number. And so what we did was, and I had one grad student that was just absolutely amazing. She took NMR spectra of 250 different bourbons that we bought commercially, and then analyzed them for the chemical concentration of those 17 chemicals. And, and we tried to get as many bourbons as we possibly could, but in our library there. We were definitely slanted toward Blanton's, because that was my favorite. And when we started seeing, we did some statistics on these very rudimentary ones because we weren't very good at this. And we could cluster the bourbons and we found out that we could tell which distillery made each bourbon. We couldn't tell which bourbon it actually was. And so we reached out to some data analytics guys at a company called Mind's Eye in Dayton. And this is this kind of stuff that, John, they love to do and they keep saying, Oh, these datasets are not big enough, and it said, two years. I wouldn't say that. And so I had seven plantain samples in our group. And then one of our collaborators in Mind's Eye, he actually had three, but he refuses to wait in line to buy his plans. He instead pays for it and gets it, you know, he goes and picks it up. And so we ran the analyses, and I was giving a talk in Lexington about two years ago. And I was showing the data and was showing the clustering and everything. And then I say now here's a blow up of the blends. And there were nine dots there. There were nine Blanton samples. And so a guy in the front row said, I thought you said there were 10 Blanton's samples in your group. And I said yeah, we thought there was, but one of them wasn't Blanton's. And the whole place started mumbling. There were 300 distillers in this room. And they were mumbling and it was all this. And so I was going to try to build up the story. But the guy on the front row didn't want to wait. He says, Well, what was it? And I said it was not created by 12 Zero. And the whole place really went nuts. And it turns out that and this one sample that we thought was Blanton's, it's, its little data point fell right on top of Knob Creek 12 Euro. And so what happened is one of those purchase bottles that this guy got sort of second hand, it was an imposter. It was a fake. And our data could show that.
Rosemary Pennington
Oh, that's incredible. Yeah, the mythic, the mythic bourbon, right, is Pappy Van Winkle. It's the one that everyone is after, is it worth chasing down?
Michael Crowder
I need a sample of that far collection just to have the spectra and be able to have the data. I think if that's something you want to do, absolutely, you should do it. You can occasionally find it in restaurants. And so instead of paying $2,500 for a bottle, it might be better to pay 154 pour and see if you really like it. And remember that the 23 year old Pappy has been in a barrel for 23 years. It is very oaky, it's very dry and astringent, it dries your mouth out. And it's not always a pleasant experience for some bourbon drinkers. I think it's fantastic. But that's the problem with a lot of bourbon, you get to where oh, man, I love this one. And then you can't find it. Yeah.
Rosemary Pennington
Yeah, I was thinking about this idea and the experience of the taste. And you know, there's expectations if you have oh, I know this is very expensive, but I'm just curious about if you have all these blind tastes evaluated, you know, sort of had these rated. And if people can then take those chemical makeups and then map that to kind of what a tasters experience is if you were blind to brand?
Michael Crowder
Yeah, so I received a grant from Buffalo Trace to do NMR on all 192 barrels in the single oak project. And so we did that. And then we're working with the data analytics people at Mind's Eye. And that's exactly what we're trying to do, to map the chemical profiles to the preferences of the consumer. And that is enough data for these people to work with. It is a ton of things. And we have found that even so the Buffalo Trace, people use an instrument called GC to actually analyze for chemicals. And there's not always good overlap or good match from what the NMR says and the GC does. So that's even another issue with data that we've got to figure out what we're doing with.
Rosemary Pennington
Well, that’s all the time we have for this episode of Stats and Stories. Mike, thank you so much for joining us.
Michael Crowder
Thank you guys. It's been great.
Rosemary Pennington
Stats and Stories is a partnership between Miami University's departments of statistics and media, journalism and film and the American Statistical Association. You can follow us on Twitter @statsandstories, Apple podcasts or other places where you find podcasts. If you'd like to share your thoughts on the program, send your email to statsandstories@miamioh.edu, or check us out at statsandstories.net, and be sure to listen for future editions of Stats and Stories, where we discuss the statistics behind the stories and the stories behind the statistics.