This is a transcript of the Gastropod episode Sour Grapes: The History and Science of Vinegar, first released on August 29, 2017. It is provided as a courtesy and may contain errors.

ANDY HARRIS: I mean, it’s still got the characteristics of the wine, that’s the thing. The better the wine the more, you know, things that you can do with it, the more flavors.

CYNTHIA GRABER: Well, and it tastes like a Riesling.

NICOLA TWILLEY: That’s delicious.

HARRIS: I almost get like banana-y flavors on that. And this I use with marinating herrings and things, it’s very good with seafood. So when you see that sort of breadth of range, you begin to see potential of the vinegars and what you can do with them.

GRABER: Vinegar, it’s not just for cleaning your house!

TWILLEY: Or killing your fruit flies. Although it is mighty good at both of those things. But really, that’s the least of vinegar’s powers.

GRABER: You’re listening to Gastropod, the podcast that looks at food through the lens of science and history, I’m Cynthia Graber.

TWILLEY: And I’m Nicola Twilley. And today, we’re diving into vinegar. Not literally, because that would sting.

GRABER: Vinegar is often relegated to salad dressing, but this episode, we talk to people who want you to think about it as much more than that. First, though, what is vinegar?

TWILLEY: And why does Katy Perry think drinking apple cider vinegar will cure basically everything?

GRABER: As usual, we have the answers to all the questions. And then—perhaps most of exciting of all—we actually visit the home of the most famous vinegar in the world.

TWILLEY: It’s like the Katy Perry of vinegars. Although much older and, honestly, more to my taste.

GRABER: That’s right, balsamic vinegar!

TWILLEY: Forget the stuff you buy at the supermarket. It is not real balsamic. Genuine aged balsamic it turns out, is game-changingly delicious.

(PRE-ROLL)

GRABER: And also, this episode would not have been possible without Toni Mazzaglia. She runs a tour company in Florence called Taste Florence. I’ve been on her tours—it’s how Toni and I first met years ago—and they are absolutely amazing. She arranged all our balsamic vinegar interviews for us and helped translate when necessary. So everyone, if you have a trip planned to Florence, go to her website and book a tour online. TasteFlorence.com. If you don’t have a trip to Florence planned, this could be a good a reason to go!

TWILLEY: And if you’re a journalist and you need help setting up visits and interviews in Italy, Toni is the best. She knows how to make Italy happen.

GRABER: So if you listened to our last episode called The Birds and the Bugs, you know that we spoke with author Maryn McKenna about the use of antibiotics in agriculture, and the move to get rid of the drugs from animal feed. One listener sent in a voice mail with a great note of hope.

CONRAD BARRY: Hi Gastropod, my name’s Conrad Barry and I’m a scientist in Portland, Oregon. I just finished listening to your Big Chicken and Big Pharma episode, and I really enjoyed it.

GRABER: Conrad explained that when bacteria develop resistance to antibiotics, that power comes at a price. They actually don’t grow as well as they did before. So in the lab, in a petri dish, if the resistant bacteria are left alone, without any antibiotics, eventually they evolve to lose that antibiotic resistance so they can grow more quickly again.

BARRY: That’s something we see all the time when we’re culturing bacteria or other cells in the lab. So that’s just something I find really cool and I interact with every day, and it’s kind of a hopeful thing, you know.

TWILLEY: What’s more, Conrad points out, if we stop encouraging it by using such huge quantities of antibiotics on the farm, bacteria could theoretically lose their resistance really pretty quickly.

BARRY: Because you know bacteria live a very short time, and a generation span is really, really short, and that allows mutations and their evolution to happen very, very rapidly. Okay bye!

(MUSIC)

MICHAEL HARLAN TURKELL: In Ancient Mesopotamia, around the city of Babylon, which is I think near where Baghdad, Iraq, is these days, along the Euphrates and Tigris River, there were tons of really plump, juicy fruit. That lead into what likely were the first wines and what comes after wine is vinegar.

TWILLEY: That’s Michael Harlan Turkell. He’s the author of a new cookbook called Acid Trip that celebrates vinegar.

GRABER: The first vinegars were from wine that had gone off—the clue is in the name. Vinegar comes from vin aigre—or, literally, in French, sour wine.

TWILLEY: And people mostly consumed those first, accidental vinegars as a beverage. Like the wine they used to be. But they quickly realized that this sour wine had other uses.

TURKELL: There are instances of it not only as this celebratory drink, but also as this currency. In Egypt, they were trading vinegars to embalmers when, you know, a family member passed. So it was a preservative in both ways.

GRABER: Vinegar was so valuable that people used it to pay to have their relatives embalmed. But, ironically, they also figured out that the vinegar could do the work of preserving the dead body itself. Vinegar has a really low pH, it’s really acidic, and that means it kills off other microbes that would make the body decay. Two for one.

TWILLEY: Like Michael says, the earliest vinegars were probably made in the Middle East, just because the first wines were made there. But vinegar is a thing that has been stumbled upon again and again, all around the world. In his book, Michael explores vinegar making in Japan and Peru and Mexico and beyond.

TURKELL: And I don’t think I fully realized until I started traveling how multicultural, how expansive the world of vinegar truly is. So there are so many starting points, so many points around the world, that preservation methods and techniques happened at so many times along history.

GRABER: In Europe, like in ancient Egypt, people started out by drinking their sour wine. Michael thinks that vinegar first made its way into the kitchen in ancient China.

TURKELL: It was a condiment, it was a dipping sauce, it was something that you poured over a bowl of noodles. It wasn’t fully integrated into sauces initially but then kind of got into the fold.

TWILLEY: But from the very beginning, people weren’t just appreciating vinegar for its ability to add tang to a sauce or preserve things. Vinegar has had a health halo as far back as Ancient Greece, if not beyond.

TURKELL: There are instances of Pliny the Elder or Hildegard or these ancients that wrote about using certain aspects of vinegar in their healing. Posca, which is an old Greek drink, was actually usually an herbal vinegar mixed with something to cut it a little bit because it was so tart. But that was used as medicine, if not a placebo to make people feel better.

GRABER: In France, there was a famous early health-promoting vinegar called The Four Thieves.

TURKELL: I can’t tell you who the four thieves were, but in modern day Provence you can still actually find this vinegar around.

TWILLEY: This Four Thieves vinegar was first made during the bubonic plague. The story, which is almost definitely not true, but is fun anyway, is that a gang of thieves were robbing the houses of people who were dead or dying of the plague. And then, when they were caught, the thieves bought their innocence by sharing their secret recipe for a vinegar that they said had kept them healthy, even in the houses of the sick.

TURKELL: It had a lot of aromatics and herbs like wild sage, rosemary—in modern days, you can find garlic in it, I think more for culinary purposes than to stave off the bubonic plague. But it was around during that time. And I think those smells and those flavors were resonant of something that was healthy or, you know, that old saying of, you know, if it doesn’t taste good it must be good for you. But then it started tasting good. And then everyone died of the bubonic plague. But that’s a whole ‘nother story.

GRABER: But now today vinegar is back in the spotlight as a cure-all. Especially cider vinegar, for whatever reason. You have celebrities including Heidi Klum, Megan Fox, Hillary Duff, Scarlett Johansson, and even explorer Ralph Fiennes singing vinegar’s praises. So we wondered, is there any truth to any of that?

WOLFE: There are a lot of claims, but the thing to keep in mind when you read any paper about the wonders of any food, anything from oranges to kombucha to vinegar, is a lot of studies start off in a petri dish.

TWILLEY: To be fair, some of the studies were done in rats too. And that voice of scepticism is one you might recognize if you are a regular Gastropod listener—it’s Ben Wolfe of Tufts University, aka our in-house microbiologist.

GRABER: That’s right: microbes. Drink now.

TWILLEY: Cheers. So there is some interesting science on vinegar’s health benefits. But the only vinegar super power that’s really well-documented is its ability to kill bacteria. They’re actually being killed by acetic acid, which is what makes vinegar vinegar.

WOLFE: So you can add, you know, high doses of acetic acid to E. coli, to salmonella, and they’ll die because of that acidity. Then translating those kinds of studies from a pure culture in a petri dish to the more complicated world of the human body, there’s some challenges there. It’s much more complicated. You know, if you drank a ton of vinegar, you know, you probably aren’t going to feel great. And that’s because your own body tries to maintain a certain pH in different places. So drinking a ton of vinegar isn’t necessarily going to make you super, super healthy.

GRABER: There does seem to be some intriguing research on the effects of consuming small amounts of vinegar on blood sugar and weight loss, but these are not definitive studies. At all. Sorry Heidi, Scarlett, and Ralph: more research is needed.

TWILLEY: In other words, vinegar is not a cure-all.

GRABER: That said, adding fermented foods like vinegar to your diet seems to be a good thing overall—if you enjoy them. Just listen to Ben rather than Heidi, and don’t drink the whole bottle in one go.

TWILLEY: But vinegar’s ability to kill bacteria is curious. Because vinegar is actually made by bacteria. Like I said, vinegar is basically acetic acid.

WOLFE: And acetic acid is a byproduct of microbial metabolism. It’s essentially waste from a certain group of microbes.

GRABER: This group of microbes is called acetic acid bacteria. And to make vinegar, they first need alcohol to eat. Which is why you can’t have vinegar unless you have alcohol first.

WOLFE: Which when you think about it, it’s not something that a lot of organisms can use. And in fact it’s actually toxic to many organisms. But for acetic acid bacteria it’s delicious and wonderful.

TWILLEY: Acetic acid bacteria cannot get enough booze. They love it. They chug their way through any alcohol you give them, they break it down, and then they sweat it out as acetic acid, carbon dioxide, and water.

GRABER: This sounds like great fun—microbe party!—but it’s actually a lot of work.

WOLFE: Why would they go through all this work to use up alcohol and produce acetic acid? And in part, it makes a lot of sense, it’s a great way to kill competitors in your environment. So if you want to grow as a microbe you have to fight with all of these things living around you. And so acetic acid is a, you know, a very strong acid. In high concentrations, the pH, the acidity of the environment is a really difficult thing to deal with for many microbes.

TWILLEY: That’s why it makes sense that vinegar preserves things, like dead bodies in Egypt and also pickles.

GRABER: So vinegar is three to six percent acetic acid. The rest is just water and a few other flavors, depending on what kind of booze you started with.

TWILLEY: And because thirsty humans have developed so many different types of booze, there are tons of different kinds of vinegars out there. Red wine vinegar and white wine vinegar and rice wine vinegar. There’s pineapple vinegar and coconut vinegar and malt vinegar. You can start with absolutely any product, as long as it has enough sugar in it to be fermented by yeast into alcohol.

GRABER: And once the yeast have done their work, then you let the acetic acid bacteria have their party.

WOLFE: Yeah, so acetic acid bacteria are everywhere. So if you walk in a field of flowers, if you even walk through Central Park or any place where there is soil, where there are plants, where there insects around, there are acetic acid bacteria. They’re living in places with little bits of sugar, like inside of flowers where there’s nectar. They’re living inside the bodies of insects. And so anywhere you have open alcohol, these bacteria can get into that environment, and that’s really where—that’s their happy place.

GRABER: And this is why, as Michael told us, those first vinegars were almost definitely an accident. The acetic acid bacteria would have just fallen in those open Mesopotamian wine containers and then, poof, vinegar!

TWILLEY: Lots of traditional vinegars are still made this way, just by relying on acetic acid bacteria in the environment to sour a jugful of wine. Andy Harris, a food writer turned vinegar entrepreneur, makes vinegar in his shed in West London in earthenware crocks and barrels. He told us that that’s a tradition that goes back millennia.

HARRIS: Traditionally in France and probably many other parts of Europe, peasant society, you know, farmers, each family would have a pot, vinegar crock, or a barrel where they made their vinegar. And that would be literally either pouring their slops from the daily wine. So then they used that as the family vinegar barrel.

GRABER: Among vinegar makers, this is known as the Orleans method. Michael told us the name comes from the town of Orleans in France that served as a stopping off point for wine coming into Paris.

TURKELL: And it had this amazing history of all this wine coming from the Loire, you know, along the Loire River and then would be shuttled up to Paris. Well, whatever didn’t make it on the boat as wine and then converted into vinegar was dropped off at the shore. So peoples or artisans there had to figure out something to do with it and they developed the Orleans method, which was one of the initial barrel-age methods of vinegar.

TWILLEY: It’s most the low-maintenance thing you can imagine. The wine sits there, the acetic acid bacteria do their thing, and then you drain the resulting vinegar off and bottle it, leaving the dregs in the barrel to get things going the next time.

TURKELL: The only one who’s left is Martin Pouret, who’s a sixth-generation vinegar maker in Orleans. And I couldn’t even walk into the vinegar cellars—or it was actually on the second, third floor—because the smell was so strong.

GRABER: At the height of the town’s vinegar production, around the time of the French revolution in the late 1700s, there were dozens of vinegar makers in town. Imagine the smell!

TWILLEY: The Orleans method is also a very slow method of making vinegar, which is fine, but has its downsides for businessmen who, you know, traditionally favor making a quick buck.

TURKELL: You have to have a lot of patience and you have to have a lot of product.

GRABER: All that changed in the late 1700s, when Louis Pasteur noticed that booze turned into vinegar more quickly if there was more oxygen in the liquid.

TWILLEY: So people started to experiment with ways to expose the vinegar to more air, first by trickling it down through beds of wood chips in a barrel, and then, more recently, using something called the Frings acetator. This is the method that’s still used to produce most of the world’s vinegar today.

GRABER: Ben told us that these acetators work by bubbling up oxygen into alcohol.

WOLFE: It’s sort of like a bubbler in an aquarium, and that continuously pumps in a lot of oxygen into the system and that happens over just a couple of days. So these microbes are capable of making vinegar over a really short time periods if the conditions are right.

TWILLEY: Whereas in Andy’s shed, his wine or beer takes as long as it takes to become vinegar—3 months, 6 months, however much time the acetic acid bacteria need to get the job done.

GRABER: So we wondered, does making vinegar faster make a difference to the flavor? And what contributes the most flavor to the end product, anyway?

WOLFE: Yeah, so I think you know in terms of the flavor of vinegar, I’d love to think that the microbes are doing a whole lot. But at the end of the day, the thing that’s driving flavor often in vinegar is what you start off with.

TWILLEY: That plain distilled vinegar or white vinegar you buy at the store is made from straight ethanol. And that ethanol could have come from corn or really any of the huge number of industrial processes that produce ethanol as a waste product.

GRABER: So it’s pretty tasteless. But then what about the red wine vinegar at the grocery store versus Andy’s red wine vinegar? They’re both made from red wine.

(DOOR OPENING)

HARRIS: And then this, this is what I call my vinegar shed.

TWILLEY: Andy used to be a food writer, like I said. So he has lots of wine writer friends who give him their leftover tasting bottles.

HARRIS: So that’s a Bordeaux. That’s a Tempranillo, a Rioja.

TWILLEY: Yeah, sadly the red wine vinegar in my cupboard is not a single varietal.

GRABER: And yes. Andy’s red wine vinegar is genuinely really tasty, better than the one I have at home. Like Ben said, the starting material really does matter.

TWILLEY: But so wait. That raises a question. Could you just put that fancy Bordeaux into one of these industrial bubblers and make really good red wine vinegar really fast?

GRABER: As usual, the answer seems to be not necessarily. First of all, Andy’s vinegar gets some great flavor notes from the wood barrels themselves. But then there’s the aging process. Ben pointed out that there’s a lot going on in the wine as it slowly becomes vinegar.

WOLFE: When these acetic acid bacteria are metabolizing the alcohol and converting into acetic acid, they’re not just doing that, right? Their cells are doing other things. And so you can imagine if you let those things sit around for a while some of those cells will die. And as those cells die, they release different things into the environment, metabolites that we can perceive as flavors. You could imagine that there would be a much more complicated microbial death cascade that could end up in some really beautiful flavors in the longer fermentation.

TWILLEY: Yep, that’s right. It’s the microbial death cascade in Andy’s vinegar that makes it so pleasing on the palate.

GRABER: Perfect band name.

TWILLEY: Cynthia, if we were a band rather than a podcast, we would totally be called Microbial Death Cascade!

GRABER: If we had any musical talent. But microbial death combined with the source alcohol is not the only way to get amazing flavored vinegar. Andy, for example—he doesn’t just make vinegars. He also has an incredible collection that he sells as well. And lots of them are infused with herbs and fruit and flowers.

HARRIS: So there’s this wonderful lady called Natalie LeFort who makes all these vinegars. This comes from a 16th-century recipe she found in a cookbook. And it’s vermeil and it’s basically with cloves and cinnamon.

TWILLEY: This is another way to build flavor in your vinegar: infuse it.

HARRIS: That for example I use with duck—duck breast. To deglaze.

GRABER: That sounds perfect.

TWILLEY: Ideal.

GRABER: The herb and spice flavors are all preserved in the vinegar.

HARRIS: These are made by nuns, and there’s a thyme flower vinegar—you just smell from the bottle. So these are very intense and savoury and all the herbs and the fruit are grown in the monastery. Tarragon. You can really get that aniseed of the tarragon in that one.

GRABER: Mmmm, I love tarragon.

TWILLEY: That’s incredible.

HARRIS: Sarayet, which is one of my favourites—savoury. Wow. It’s a really earthy. So that with a lovely warm potato salad. You know, just get some waxy potatoes and just literally just get them out the pan, add some of that and some good olive oil and some nice sea salt.

TWILLEY: We had an epic vinegar tasting session at Andy’s, and it really was easy to see how these super-flavorful infused wine vinegars would add a whole new dimension to a dish.

GRABER: With Andy, though, there’s one crucial vinegar we did not taste. Because we knew we were headed to Italy to taste it in its home. Balsamic vinegar.

TWILLEY: The top dog of vinegars. But when did balsamic get so popular? And is the balsamic you’ve tasted actually the real thing?

GRABER: Answers to all your balsamic questions and more—right after a few words about our sponsors this episode.

(MIDROLL)

EMILIO BIANCARDI: OK, what you see here is one of our robotic lawn mower. We were the first one to introduce robotic lawn mowers in a vineyard.

TWILLEY: Here we are, surrounded by grapevines, near a 18th-century villa, in the gorgeous Italian countryside. And this oversized lawnmower roomba-thing is following us around.

BIANCARDI: Yeah, that’s Inea. Well, Inea in English. We have Mario, Pepo, Inea and Ulisa, Ulysses. So we decided to give them name.

GRABER: This is where balsamic vinegar comes from.

BIANCARDI: My name is Emilio Biancardi, from Antica Acetaia Villa Bianca. We’re in the zone of origin for traditional balsamic vinegar of Modena, which is just the province of Modena.

GRABER: People here have been making vinegar here for thousands of years. Christina Sereni works in the Museum of Traditional Balsamic Vinegar, not far from Emilio’s vineyards.

CRISTINA SERENI: We know that we were famous for vinegars even in Roman times. We cannot grow olive trees, we cannot grow lemon trees. Winter frost kills everything. We know that we were growing grapes even in Roman times. Apicio, one of the chefs of the Roman Age, was using vinegar from Modena and he writes it in his recipes. So we know that in Roman times we were already famous for our production of vinegars. And I’m using the plural because we had many, many vinegars. Different kinds of vinegar, made in different ways with apples, with grapes, with wine or cooked grape must.

TWILLEY: Cooked grape must—that is the thing that sets balsamic apart. Must is just the pressed wine grapes—juice, seeds, skins, stems, and all. And then that must is cooked for between 12 and 72 hours. It’s brought to the boil, and then gently simmered.

BIANCARDI: That’s the secret of our product. And it gives us these four major effects: volume reduction, sugar concentration, almost killing of all the enzymes and bacteria that can lead to an alcoholic fermentation. And, last but not least, the first change in the color, due to the caramelization of sugar and to the Maillard reaction.

GRABER: The Maillard reaction is a chemical reaction from heating proteins and sugars that makes things brown and tasty, like the brown top of a loaf of bread. Same thing is happening to the cooking grape must. And like Cristina said, it’s not just that they’ve been making vinegar in Modena for thousands of years, but they’ve also been cooking grape must for just as long.

BIANCARDI: The idea of cooking must comes from the Roman. As you may know, the Romans didn’t have any sugar. They just had honey and cooked must. This was one of the sweetest things that they had.

TWILLEY: Cooked must, which is called saba in Modena, it’s still used as a sweetener in the region today, to make Christmas confectionery. In fact, quite a few places still have that tradition, left over from Roman times. Emilio told us cooked must is big in Romania too.

GRABER: And like everywhere else in the world where vinegar has been invented, that sweet, cooked grape must turned into alcohol and then vinegar, by accident. And unsurprisingly, it was delicious. People loved it.

TWILLEY: That happy accident was the first balsamic vinegar, the grandaddy of all the balsamic vinegars we drizzle today. Balsamic vinegar is, by definition, cooked grape must, aged.

GRABER: This sounds simple, and yet bottles of real balsamic vinegar cost about 50 bucks minimum. So obviously it’s not quite as simple as it sounds.

TWILLEY: For starters, you can’t just use any old grape.

BIANCARDI: Our productive law says which kind of grapes we have to use. So the trebbiano, ancellotta, lambruschi. So typical grapes from the zone of origin.

GRABER: So far, so straightforward. Then it gets a little nuts. We went upstairs at Emilio’s villa into his balsamic attic.

TONI MAGLIAZZA: Neither of you have been in a balsamic attic before?

GRABER: No.

MAGLIAZZA: Prepare yourselves, have the mic on.

GRABER: Oh the mic’s on, it’s not off.

MAGLIAZZA: You’re gonna freak out, it’s life changing.

TWILLEY: Even though Toni warned us, we still freaked out. We got out of the elevator and it hit us right away, square to the nose.

TWILLEY: Ohhhh! Smell that!

GRABER: Wow. It’s sweet and it’s acidic and it’s warm.

BIANCARDI: Well it’s warm because I left the—

GRABER: No, I mean the smell is like really a warm smell.

TWILLEY: Like a little spicy, wood.

GRABER: Little caramel.

BIANCARDI: OK, follow me.

GRABER: Wow. Oh my gosh.

BIANCARDI: Watch your hand, watch your step please.

GRABER: As Emilio started to say, it wasn’t just a warm smell, which I loved, but it was also really freaking hot.

TWILLEY: Which, it turns out, serves a purpose. Because once you’ve got your cooked must, you use it to refill a barrel that’s half-filled with older balsamic. And then you leave it for an entire year, winter followed by summer. And the magic starts to happen.

BIANCARDI: The fluctuation between hot and cold is really important. Because the acetic bacteria are really active when it’s hot. So in winter when it’s cold and calm you have sediment.

GRABER: And, after a cold calm winter and a busy hot summer, the sugar in the must has turned into alcohol. And it’s starting to turn into vinegar. Andy’s red wine vinegar would be long done and bottled by now. But Emilio is nowhere near finished.

BIANCARDI: Even if it seem a really calm and slow product, it’s really dynamic product. You have to keep the product alive.

TWILLEY: This is what Emilio has to do to keep his balsamic alive: Every year, once a year, he has to go up to the attic to sniff his barrels, and then move some of the vinegar from one barrel to another. And then the vinegar that was in that 2nd barrel … well, some of that gets moved to a third barrel. Which some of the vinegar from that third barrel has to be moved into a fourth. And then some of the vinegar from the fourth… You get the picture.

GRABER: Each barrel down that path year after year is smaller. In part, it’s because you’re only moving some of the vinegar from one barrel to the next. In part, it’s because some of the liquid evaporates over the course of the year. And so, up in Emilio’s attic, there are all these beautiful rows of barrels, each progressively smaller in that row.

TWILLEY: This process of moving just a little bit of the aging vinegar each year—it can be as little as a litre, like a couple of pints—it’s called the passages. It happens every spring.

SERENI: When temperature rises yeasts and acetic acid bacteria start to wake up. And they start to work. So you understand that the time is right by the perfumes you are perceiving.

TWILLEY: That’s why Emilio sniffs his barrels to know when to start the passages—you can smell when the acetic acid bacteria have woken up from winter hibernation and rolled up their sleeves to start another long season of eating alcohol.

GRABER: So each of those barrels in a set, it gets a little bit of the vinegar from the barrel before. So in each barrel, there’s vinegar there from the very first year that the barrel was ever used to make vinegar.

TWILLEY: This is why when you buy balsamic—the real aged traditional stuff—it always says it’s either at least 12 years or at least 25 years old

BIANCARDI: So what does it mean? The first one you tasted, I told you it was at least six. But this barrel contains all the product that we’ve been putting inside this barrel from the beginning of the life of the barrel.

GRABER: So why don’t you just leave the product in one barrel and age it there for six years? Why this whole moving a little bit each year thing?

BIANCARDI: You wouldn’t have the same complexity and taste that we are achieving now. So adding something every year is making them more active.

TWILLEY: It’s all about keeping the balsamic alive, not letting it get stuck. But the moving, adding young blood to the older barrels—that’s not the only thing contributing to balsamic’s flavor development. There’s also the wood of the barrels themselves.

GRABER: Cristina told us they use woods they can get in the region.

SERENI: Oak and acacia are sweet and warm. Mulberry and cherry are fresh and fruity. Ash is very delicate. Chestnut is tannic, but because it is the cheapest, everyone’s got a barrel of chestnut. And we use to sweeten the flavor given by chestnut with oak. Oak is the most used for smallest barrels. And the one in the middle is juniper. Juniper is a very aromatic and spicy wood, so aromatic and spicy that you can tell if a vinegar has been kept in a barrel made of juniper simply by smelling it.

TWILLEY: Over the years that the balsamic is moving along into smaller and smaller barrels, its flavor is being transformed. Emilio gave us a taste of the at least six-year-old balsamic, which is actually too young to legally sell. It tasted fine to me, but kind of acidic—a little sweet and thick but really more like regular sherry vinegar.

GRABER: Then we moved on to the good stuff.

BIANCARDI: But let’s continue so you see how the product is following its path to the excellence. Ready?

GRABER: Yeah.

TWILLEY: Yeah.

BIANCARDI: OK please, poker face. OK, don’t tell the others what you’re feeling. I don’t want—

TWILLEY: The world to know?

BIANCARDI: This one is at least thirteen, more or less. That was one of the worst poker face I’ve ever seen.

GRABER: We don’t do poker faces here.

TWILLEY: So it’s become sweeter. It’s become thicker. It’s also become…

BIANCARDI: Rounder.

TWILLEY: Yeah.

GRABER: And more caramel notes to it too.

TWILLEY: So here’s the funny thing. I have no idea how some lunatic Modenese person first decided to do this whole kind of painful process of transferring just a tiny bit of vinegar into a smaller barrel each year. No one really does.

SERENI: We have a record that tells us that in 1046, a German Emperor, Henry the Third, going to meet the Pope stopped in this area to collect a bottle of vinegar, that from the description could have been an ancestor of this traditional balsamic vinegar. But we haven’t found a barrel, we haven’t found any recipes dating back one or two thousand years. So only we can tell you is that we found a record.

TWILLEY: There’s also a record in the 1500s of Lucretia Borgia, who has something of a reputation—the Borgia family specialized in poisonings and murder—but she apparently specially requested the famous vinegar of Modena to ease her labor pains.

GRABER: The name ‘balsamic vinegar’ was first used, as far as we know, in 1747. It was another name for ‘the Duke’s vinegars’ that were kept in his secret cellars. The name is from the Latin balsam, like a thick aromatic balm.

TWILLEY: But balsamic wasn’t only for the duke.

SERENI: In ancient times, families used to start a new set anytime a baby girl was born. In this way, when the girl was ready to leave the house, usually because she was getting married, the vinegar was already good.

TWILLEY: Cristina’s family started a set of barrels for her when she was born. She’s not married, but she’s used her own vinegar anyway.

SERENI: Now the tradition stays on. But people don’t mind the gender. Anything can be a good excuse to start a new set.

GRABER: So people were doing this—cooking grape must, moving it from barrel to barrel in an attic. But there wasn’t a clear defined step-by-step, this is what you do to make balsamic vinegar, until…

SERENI: The first record, the first recipe describing in detail is the process that we still use to make traditional balsamic vinegar is described in one of the letters Pio Fabriani and Francesco Aggazzotti exchanged between 1860 and 1862. He was just describing the method his family was following to help his friend to make a better vinegar.

TWILLEY: This letter was the first time that these specific steps were spelled out. But nowadays, they’re law.

GRABER: Emilio’s family has been making balsamic vinegar this way for at least six generations back. Today, they make 5000 to 8000 bottles a year.

TWILLEY: But they don’t put their own vinegar into bottles. They’re not allowed to.

BIANCARDI: So you will have to bring the product to the consortium, whole amount.

GRABER: There’s a special consortium, they’re basically the guardians of balsamic tradition, and they decide whether the product is good enough to be called “traditional balsamic vinegar of Modena.”

BIANCARDI: There the product is tested and tasted by experts. They test it for minimal acidity, minimal density, and then taste it. And if the product is OK, they do the bottling.

GRABER: Cristina was a master taster and would have been one of people judging vinegar like Emilio’s, though she’s no longer doing it these days.

TWILLEY: It had taken over her life. If you’re a taster, you spend more time tasting than you do with your family.

GRABER: At the museum, Cristina talked us through what she used to do, and what tasters still do, every day in Modena.

SERENI: This is a typical table used to taste traditional balsamic vinegar. Six people gathered around a table, and first of all they checked the color of the vinegar through the light of a candle. When you check the vinegar through the light of a candle, you look for the perfect density. The color must be dark with ruby flecks and it must be clear.

TWILLEY: Then they sniff it. Cristina told us you’re looking for an aroma that sticks around. It needs to have lasting power but still be delicate.

SERENI: You want to have a refined perfume, not too aggressive.

GRABER: And then they taste a few drops. They spread the vinegar around on their tongue and press it to the roof of their mouth.

SERENI: Then you look for a body, when you taste it in your mouth, you look for a body. You want a vinegar that remains there even when you swallow it. The flavor should be nice and harmonious. And then it must be sour, because vinegar is sour, it must be sour, not too sweet, not too sour. Everything must be very well balanced and refined.

TWILLEY: And then they talk about the vinegar and they give the vinegar a score.

SERENI: Sometimes there are discussions that goes on for minutes and minutes. Some other times you find people that agree about the quality of the vinegar. The highest possible score is 400. Nobody got such a high score.

GRABER: The best vinegars get about 320 or so. But if it’s not quite good enough to be called real balsamic vinegar of Modena, the guardians of tradition might send the producer back to age it another year or so. And that’s it. This is traditional balsamic vinegar of Modena.

TWILLEY: Balsamic vinegar was a pretty local product for a very long time. European aristocracy might have craved it, but the majority of world had no idea it even existed. And then suddenly—and I remember this happening—you couldn’t move for a balsamic-drizzled Caprese salad. What happened?

GRABER: A few things happened within just a decade or so. In 1976, Chuck Williams—he’s the founder of Williams-Sonoma—he first saw and fell in love with balsamic vinegar in Italy. At the time it was almost impossible to find here. So In 1977, he imported some in his Williams-Sonoma catalogue, and apparently it was really popular. He’s credited with starting the balsamic craze in America.

TWILLEY: Although Emilio’s theory is that balsamic really became big a little later.

BIANCARDI: It was in the 90s, I think because I remember in Star Trek, in one of the movies, there is Captain Picard says something about “serve to the aliens some balsamic vinaigrette,” something like that. So it was in the 90s.

STAR TREK EXCERPT

TWILLEY: But something else happened in the 1990s, too.

BIANCARDI: This was the moment of the fight, you know. Our tiny consortium was fighting to receive this protection from the European law and the European Union. But then everything went wrong.

GRABER: As we said, the real balsamic vinegar is super expensive, at least 50 bucks for a small bottle. And now you understand why—it takes years to make. But balsamic vinegar in America suddenly was super popular. So of course, copy-cats started to elbow in on Emilio’s family business.

TWILLEY: His family and the consortium—the balsamic guardians—they wanted to say that the only product you could call balsamic vinegar was balsamic vinegar made the way they make it. But they lost.

GRABER: There is actually a law about what can be called ‘balsamic vinegar of Modena.’ It does, yes, have to be made in Modena. But there are industrial shortcuts you can take. You can make it with wine vinegar, for instance, which, as we know from Andy, takes a lot less time to produce.

BIANCARDI: Wine vinegar, concentrated must, caramel. Whatever.

TWILLEY: This more industrial, faster product—it’s cheaper, obviously. And it’s not bad. In fact, for years, it was all I knew. It’s all many Italians know. And it’s legally sold as traditional balsamic vinegar of Modena with an IGP label—a protected geographical indication. So it looks really legit.

GRABER: As Nicky said, it’s not bad. But it doesn’t have the same complexity and depth of flavor. And, frankly, the grapes don’t even have to come from Modena.

TWILLEY: So if you want the real balsamic—the stuff that Emilio and Cristina make, painstakingly transferring vinegar between barrels each year—you need to be specific. It has to be called traditional balsamic vinegar of modena and it has to have a DOP symbol—a protected designation of origin. Which is confusing, because the IGP label really looks quite similar.

GRABER: Let’s make this all even a little more confusing for you, and more frustrating for Emilio. If you go to the supermarket and you see something called ‘balsamic vinegar,’ no mention of Modena, it could just be industrial wine vinegar with added sugar. That’s what most of the stuff in America is. You can tell, too—it flows like water, it’s not thick at all. It’s just slightly sweet vinegar.

TWILLEY: I would say be careful here. If you do try the real stuff, it’s very hard to go back! And it’s a really expensive habit, although a little does go a long way. But oh my god is it good.

GRABER: Emilio cooked us lunch, homemade focaccia and all, and spared no expense on the balsamic vinegar.

BIANCARDI: One of the most common appetizers is Parmesan cheese with traditional balsamic vinegar. So we’re drizzling some drops on the Parmesan. And then you will tell me how it tastes.

GRABER: I can already tell you how it tastes.

TWILLEY: I’m looking forward to it. I’ll just put it that way.

GRABER: I could see the future, and I was right. It was just as delicious as I’d expected.

BIANCARDI: So that’s the frittata with the zucchini.

GRABER: With some balsamic.

BIANCARDI: And on top we’re pouring some traditional balsamic vinegar on top of it. I don’t know if you want to take a picture of that.

GRABER: In a beautiful shape of a spiral.

TWILLEY: At this point, I asked Emilio whether he just puts balsamic on everything, because everything tastes better with it.

BIANCARDI: I put balsamic. Yeah.

GRABER: The frittata was amazing. I’m going to start drizzling balsamic on all my eggs. If I can afford it.

TWILLEY: I am afraid that podcasting and a balsamic habit may not be compatible. Then to finish our balsamic feast, Emilio brought us some gelato drizzled with the at least 25-year-old balsamic.

TWILLEY: It looks like hot fudge sauce. I have a feeling it’s going to taste a lot better.

GRABER: I was going to say, this is much more appealing to me than hot fudge.

TWILLEY: Toni—her eyes literally rolled backwards in her head at this point.

GRABER: Nicky, so did yours.

TWILLEY: If I could only have one ice cream topping in the world for the rest of all time, it would surely be this. Like no competition at all with anything ever.

GRABER: We kept asking everyone in Modena if anyone else in the world makes a similar vinegar, something this sweet and rich and complex. Of course, they’re Italian, they said nobody else. Just them. But Michael—he’s the one who wrote the cookbook on vinegar—he told us about an insane Japanese sweet potato vinegar that smelled like Beaujolais but was really sweet.

TURKELL: Akihiro Io who is a many generation vinegar maker who has taken it over from his father and mother in the past few years poured it over vanilla ice cream. And I have a little bottle of that vinegar, it’s called Benimosu, at my house specifically to kind of like blow people’s mind and pour it over ice cream for dessert.

TWILLEY: And that’s the thing. For Michael and also for Andy, it’s not about, ‘Oh you have to spend 50 bucks on fancy balsamic.’ Yes, fancy balsamic is amazing. If you get the chance to try it, you have to. But their point is, vinegar in general is so much more than the industrial product most of us have on our shelves.

TURKELL: It’s often overlooked as something that’s important

GRABER: Because most people think of it just for salad dressing. Which Michael doesn’t mind.

TURKELL: But then when everyone starts thinking that, ‘Oh yeah I have vinegar and I do this, you know, I get fruit flies with it.’ I hate that vinegar has somehow been relegated to cleaning more than it has to culinary purposes.

GRABER: Andy and Michael are campaigning to break vinegar out of its salad dressing bottle. We had it on eggs in Italy. Andy uses it in casseroles and paella and gazpacho. Michael has an entire book full of recipes that require vinegar. Me, personally—I almost always splash some at the end when I’m cooking greens or other vegetables.

TURKELL: Acidity is one of those, you know, handful of elements that needs to happen in a well balanced dish. And I know a lot of chefs—actually I’ll say most chefs will say if a dish is missing something, it’s usually acidity. So I think a lot of people just don’t even know how to use it. They’re a little scared of what vinegar is.

TWILLEY: I know before we made this episode, it wouldn’t have ever crossed my mind to add a dash of vinegar to my stew or my pan-fried fish or whatever. At most, I would use like a squeeze of lemon to add that acidity.

HARRIS: If you go into supermarkets, it’s rather second-rate balsamic and a few other vinegars. So you know every—people have kind of discovered good quality olive oil and how you can use different oils for different things and they should be able to do the same with vinegar.

GRABER: That’s really the point, as we discovered in Andy’s shed. There are so many different vinegars, each with its own acidity level and flavor. Andy loves the cinnamon and cloves-infused vinegar to deglaze the pan when he’s cooking duck, and he uses a cider vinegar to poach rhubarb.

TWILLEY: Vinegar: the gateway to a new dimension. As Captain Picard never said.

(MUSIC)

GRABER: Once again, a huge, huge thanks to Toni Mazzaglia for arranging our balsamic vinegar tours and translating and making everything happen. Go to Florence and take her food tour: TasteFlorence.com.

TWILLEY: Thanks to Andy Harris of the Vinegar Shed, Michael Harlan Turkell whose new book is called Acid Trip, and then, in Italy, Emilio Biancardi of the Antica Acetaia Villa Bianca and  Cristina Sereni of the Museum of Traditional Balsamic Vinegar in Spilamberto. We have links to their books and their online shops so you can buy vinegar and cook with to your heart’s delight. It’s all on our website, along with lots of amazing photos of our vinegar adventures. Gastropod.com. And I have to thank my parents for cutting out and saving an article about Andy Harris for me: they provide a dedicated clippings service for which I am extremely grateful!

GRABER: And of course, thanks to Gastropod’s in-house microbiologist, Ben Wolfe of Tufts University. He answered all our appropriate vinegar questions, and then some that were maybe not quite in his wheelhouse.

TWILLEY: The other thing people do is they put it on their hair in the shower to make their hair shiny. Why on earth would that work? Would it?

WOLFE: Um, again…

TWILLEY: LAUGHS A tiny bit outside your expertise.

WOLFE: Sorry.

GRABER: We’re taking you way out of…

WOLFE: Yeah.

TWILLEY: I know, I’m like ‘Professor of Hair Shininess at Tufts Ben Wolfe said…’

WOLFE: LAUGHS I could put that on my CV somewhere. You know, I think it makes sense that these acids are really good at denaturing proteins. And so they can help loosen up and denature proteins that are stuck on things and other, you know, fats and other kinds of things that can help solubilize those. So it does make sense to put vinegar on your hair, it’ll probably clean your hair. But again, yeah, I’m not a hair specialist.

GRABER and TWILLEY: LAUGHING Sorry.