Fatu Badiane-Markey 0:12
Hello everyone and welcome back to the show: We Love Science. My name is Fatu.
Shekerah Primus 0:17
And I'm Shekerah. And today we have part two to our last special episode of "Food Science about Yeast". So this is a very special treat for you and we know this episode was very, very popular.
Fatu Badiane-Markey 0:32
Yeah, so we do indeed. The topic so nice, we had to do it twice. I really enjoyed our last discussion on yeast. Today we're gonna dive into how yeast are used in winemaking. Before we get started, how are you doing Shekerah?
Shekerah Primus 0:51
I am so excited, if you can't tell. I have my wine here, ready to talk about winemaking.
Fatu Badiane-Markey 0:58
Oh my goodness!
Shekerah Primus 1:00
I got an extra glass for you as you can see
Fatu Badiane-Markey 1:02
Thank you! You came prepared
Shekerah Primus
I'll drink it for you too! What about you Fatu?
Fatu Badiane-Markey
I'm doing pretty good. I'm also really looking forward to this episode. So I guess this question already kind of answers itself. But do you like wine Shekerah? Oh, yes. Are there any kinds that are your favorites?
Shekerah Primus 1:25
Oh, that is a good question. I prefer reds for sure. During the day, I'm drinking a marlot. Marlot tends to be a little dry for me sometimes, which I don't prefer. So I've actually mixed it with the Reisling which is kind of like a sweet white
Fatu Badiane-Markey 1:48
Is that allowed?
Shekerah Primus 1:48
Yeah, I do my own thing girl
Fatu Badiane-Markey 1:54
I've never heard of that in my life, but I will take your word for it. Awesome. So I don't I don't drink so I don't have a good answer. I may have had a couple of like, no wait, I've had a non alcoholic champagne, which was actually pretty good.
Shekerah Primus 2:11
Yeah.
Fatu Badiane-Markey 2:12
I don't think I've come across non alcoholic wines yet. But I do like grapes. And in general I prefer like the red or purple grapes or the green ones. And there's this one time and I haven't come across these again. Where I got these grapes that were like long. And they were literally like almost like--you know how groups are usually round? They're almost like an oval. And they were called Witches Fingers. And they were just like the most amazing things ever. So you know that's kind of like I guess my little two cents on this.
Shekerah Primus 2:40
Do you like, black grapes. What you call it purple. The black ones?
Fatu Badiane-Markey 2:45
Yeah, the darker ones.
Shekerah Primus 2:49
Because those are usually pretty sweet, right? The green ones do tend to be more crunchy and I've found.
Fatu Badiane-Markey 2:58
Someone else was telling me that we just something I'd never really thought about in terms of them being like more crunchy. I don't think I ever thought about like, texture. Yeah, I don't know. Doesn't seem to be my kind of thing. So let's jump into our wine conversation.
Shekerah Primus 3:16
Yeah, I promise I won't get drunk.
Okay, so Fatu. When did people first start making wine? I've seen all those old movies. They've been drinking wine forever.
Fatu Badiane-Markey 3:34
Yes, they have! Yes they have! The funny thing is like no one really knows like exactly when it started. Just you know have like a good general idea and we know that wine and other fermented drinks have been around for a very very long time. So winemaking and beer making literally goes back 1000s of years in human history. And archaeologists have found the remnants of wine from like archaeological sites that date back, you know, 7000 years. So wine has been around, you know, beer, a lot of fermented drinks have been around for a long, long time. And as far as you know, humankind's first encounter with like fermented beverages. The hypothesis is kind of that this happened by chance. So I'm going to set the scene for you. Imagine back in like prehistoric times, there's this dude will say he's like a thief, right? Like in someone's cave. He's rummaging through stuff, trying to steal something that might be valuable. They could sell on the black market later. And then somewhere tucked away in the back of a cave. He finds this container of overly ripe sweet fruit in a syrup. And you know, he's kind of like, yeah, I could use a snack. So he takes a quick smell, you know, doesn't smell like it's gonna kill him. And he decides to take a drink. And the flavors are completely different from what he's used to. But then following that, he's gonna just feel like this amazing form, right? You're gonna feel great, he's gonna laugh. He's gonna feel powerful, and he's just gonna go on the rest of his day and have a good time. The next morning though, when he wakes up, he's not gonna feel as good because he just drank a whole lot of some fermented stuff that's been sitting around for who knows how long. He's gonna wake up with a headache. It's gonna be maybe in a little bit of pain, a little bit cranky, maybe a little bit dizzy, just feeling miserable. So he's gonna have the first hangover
Shekerah Primus 5:21
The first hangover. There's a trophy for you.
Fatu Badiane-Markey 5:26
You know back in the day, you're just finding stuff by chance, drinking it up. You know what that's gonna do to you? Right? And so since this first accidental hangover cultures throughout time have perfected their own styles of fermented beverages, so if you look to like the Asians, the Greeks, the Celts, and others, they make mead or honey wine. In South America, they have a drink called chica, I'm sorry chicha, which is made from grains or fruit like corn, and the Egyptians and Romans are known for making wine from grapes and beer from malted barley.
Shekerah Primus 6:03
Very cool. So your hypothesis is that humans discovered how to be like drunkards totally by mistake, which, you know, as we know, a lot of things happen by accident. A lot of discoveries happen by accident.
Fatu Badiane-Markey 6:27
I know, I personally believe it, because, you know, like stuff gets left out back then you don't have refrigeration. You're not trying to waste anything and then just over time people like notice, right, cause and effect. And you know, they you know, try and kind of like perfect things and are like okay, if I leave my grape juice out for like a week. Let's see what happens, if they leave it out for two months. Let's see what happens. And then I think they get it to a point where it's like a little bit more consistent, and everyone can have a good time.
Shekerah Primus 6:55
Sounds good to me.
Accidental beautiful discovery.
Fatu Badiane-Markey 6:59
Yeah literally, so the process of fermentation. You know, like I just explained, it was perfected over time, mainly through trial and error. Because honestly, no one really understood how it worked. It was just kind of like, I leave this out for a little bit, magic happens, and then I end up with a fun drink.
Shekerah Primus 7:15
Do we know, like, what exactly people did to make my wine, can you give an example like after they figured it out? Can you give an example of what people actually did?
Fatu Badiane-Markey 7:29
Yeah, so if you'll remember, I'm sure you have seen this before. And I know I have, where they have kind of like the reenactments where people will have like, buckets full of like grapes and they squish it with their feet. That was like for reals, you know. Back in the day, people would use their feet to help soften, you know, this grape mixture before allowing it to sit and ferment. And this is where the star of our show comes in. So the yeast that was on people's feet during that time, got transferred, girl. We're going to transfer the yeast to the squish grape mixture and that would facilitate the fermentation process and then would produce wine. You know, again, that's just adding like one more layer of consistency. But still, no one really understood this back then they were probably just like, well, maybe slightly dirty feet are better than super clean feet? I don't know what they were using back then? Still a little bit of a mystery, but at the end of the day, people were kind of getting what they wanted.
Shekerah Primus 8:35
So they all thought it was about the feet.
Fatu Badiane-Markey 8:39
And I'm sure some people's feet are better than others. You know, they're going by observation.
Shekerah Primus 8:45
I feel like in some parts of the world they still use that, you know, stomping on the grapes thing I know that. Like, I don't know, I think maybe Spain and Italy they have like these tours of wine vineyards where tourists can actually like stomp on the grapes with their feet.
Fatu Badiane-Markey 9:04
Doing it old school.
Shekerah Primus 9:07
Yeah, yeah, that's pretty cool. Interesting. I'd like to try that.
Fatu Badiane-Markey 9:11
If I think about it, it's not that it didn't work. It's just like nowadays, you know, people like to use like machinery to do all that right and maybe get it to be like a little bit more clean. And you know, like there's reasons why it was phased out but it's, you know, if it's you and a few of your friends, why not?
Shekerah Primus 9:24
Also being consistent, right. So, when did people start actually researching fermentation to like understand this process and get it better?
Fatu Badiane-Markey 9:37
So, it has a pretty long history actually spanning over 100 years before we landed on sort of what our modern understanding of fermentation is that we use now. So in 1789, and just to preface a lot of French guys and with a French chemist named Antoine Lavoisier.
Shekerah Primus 9:56
Lavoisier. Oh my god.
Fatu Badiane-Markey 10:04
He discovered the chemistry behind fermentation. So he did a bunch of experiments fermenting sugarcane. And Lavoisier determined that depending on the ratio of sugar to water in the initial reaction, the sugars get broken down into two products: alcohol and carbon dioxide. And the carbon dioxide are the bubbles that you usually see that are associated with fermentation. Interestingly, though, he had to add yeast paste to his reaction to get it going, right. But even with having this like, I guess you could say, essential ingredient to get the fermentation going. There was still this general assumption that the yeast didn't really take part in any of the essential chemistry they just kind of had to be there but they weren't really doing anything, right. But by the mid 1830s, Charles Cagniard, a French inventor, he made the observation that used are a living organisms and could multiply during alcoholic fermentation by budding. And so over many, many years, additional observations were made, you know, by others. And finally, the conclusion came forward that yeast were not just bystanders in the fermentation process, that they were required for the process because they do the work, right! So then in the 1850s, Louis Pasteur studied yeast and fermentation even more closely, and through his work, we now have a modern understanding of yeast as a living microorganism, and their ability to convert sugar or usually what we would call glucose into alcohol. And he published his work in a paper titled "Mémoire sur la fermentation alcoolique"
Shekerah Primus 11:43
Oh my God, I just love that you can sell these French words girl and make it sound so Frenchie and perfect like I would say, like, what do you say? That Charles Cagniard, I was like, Cagniard. Can you tell us like the French thing again?
Fatu Badiane-Markey 11:58
The 1830s guy? Yeah, I pronounce his name Charles Cagniard?
Shekerah Primus 12:04
Cagniard oh my gosh, yeah, that's Charles Cagniard.
Okay, what do we know about winemaking today?
Fatu Badiane-Markey 12:16
Yeah, so grapes have many different types of varieties of yeast that just grow naturally on their skin. And those are thought to play the main role in fermenting the sugar of the grapes to alcohol. So for example, these pronunciations aren't going to be as good as the French just a heads up. So you have like Brettanomyces, Candida, and Kloeckera are some examples of varieties of yeast that you might find naturally on grapes.
Shekerah Primus 12:43
That was perfect.
Fatu Badiane-Markey 12:43
I hope! You know some people are going to come after me. So researchers and winemakers who study this process they found that these initial yeast strains that are associated with grapes naturally only help to start the process and they die quickly once the alcohol concentration reaches over 5%. Just because they don't have as good of a tolerance for it right when it gets that high. But then our good friend Saccharomyces cerevisiae, takes over and finishes the job. So it can survive in much higher alcohol concentrations. I think I was reading up to even like 20% alcohol by volume. And that basically you just have natural selection. It's it's going to be survival of the fittest, and Saccharomyces will take over the culture. And, you know, just like we learned last time with bread making. We know that Saccharomyces exists naturally in the environment of wineries--so it's going to be in the air, in the walls and the equipment, on the people. And so it can just be introduced naturally or unintentionally to the winemaking process.
Shekerah Primus 13:07
Hmm. So now, that isn't considered to be dangerous to the winemaking process then?
Fatu Badiane-Markey 13:57
No. I think the biggest issue is just--and there are wineries out there that do like sort of like natural fermentation--is that you don't have good control with what's going on, which can make it a little tricky if you want consistency.
Shekerah Primus 14:12
Gotcha. Okay, very cool. So, our commercial yeast ever used in winemaking?
Fatu Badiane-Markey 14:19
Yeah, they are and it isn't always the case. You know, in winemaking like I was just saying sometimes wineries will just use like natural fermentation. But researchers, wine consultants, and winemakers they will often perfect their fermentation process to bring out like unique flavors and textures by using different combinations of commercially available strains. So you can literally have yeast strains, you know, that are kind of like, I guess you could say specialized or perfected to bring out certain flavors because what people have found over time is that even the way that they break down the sugars in the grapes is not always like exactly the same for every yeast even though you end up with the same end products. It's kind of like depending on how the sugars in the grapes are sort of like combined with like other properties of the grapes will influence how the yeast then are able to kind of like break those down and so you can then like mix and match different combinations to pull out like different flavors in the grapes. You can also do things with like temperature and like you know also just like timing, the length of fermentation that will also pull out these different flavors that wine wine makers are trying to get out in their final product.
Shekerah Primus 15:38
Wow, very, very complicated process. And yes, something to think about next time you enjoy a nice glass of wine with dinner, or podcast recording, or hanging out in the afternoon on a balcony, or just chatting with your friends
Fatu Badiane-Markey 16:03
Or after a long day
Shekerah Primus 16:04
Or you're doing your puzzle. It is good for all occasions.
Fatu Badiane-Markey 16:19
There's just so much that goes into it. You know, it's really fascinating. Yeah. You know, and for me, even though I don't drink I just think it's so cool how like we have this one single celled microscopic organism right Saccharomyces and that has influenced our lives, influenced society, influenced culture. It's just like so amazing. You know what this little tiny thing can do?
Shekerah Primus 16:42
I love wine and I love yeast because yeast make wine. Thank you, everyone for joining us for today's Real Food Science chat. If there any foods you want to learn more about, please let us know. You can reach us at love science podcast@gmail.com. And remember, sometimes the best experiments start in the kitchen. By everyone!
Transcribed by https://otter.ai