Short Wave - The Science of Making Bread

Episode Date: April 14, 2020

Social distancing has some of us taking up bread baking for the first time, including host Maddie Sofia. Chemist and baker Patricia Christie explains the science of making bread, including a few tips for when things go wrong with your bread dough. And she offers some advice for first-time bakers everywhere.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Maddie Safaya here, I don't know about you, but these days I've been working hard to keep myself both occupied and distracted at home. Which means, yeah, I have jumped on the bread baking bandwagon. It could have gone better. It could have gone about 100,000% better. My first attempt at sourdough bread. Okay, so you're not supposed to let it sit on here too long. I got to say, maybe it's just me. I'm just going to flop. But my new hobby is not easy.

Wow, it's amazing how it was in a nice little look. Honestly, it's slowly making me question my value as a human being. It's not, it's not cute. We're just going to cook that for 20 minutes and see if it looks like bread. So I've called in some special reinforcement. Are you ready to talk some food and some science, my two favorite things? Of course. Oh, yes. I know I am fren enemies with my treadmill now so that I can continue to eat since I am not moving around as much as I used to.

That's Patricia Christie, a lecturer at MIT, where she teaches a course called Kitchen Chemistry. A chemist and a cook, Patty sees a clear link between the two. Scientists... They go into the lab, they do a protocol. A protocol is basically a science recipe. They have a result, and they keep a notebook. In the kitchen, you can do the same thing, but you get an edible experiment at the end, and you can try it and share it and enjoy it.

So today on the show, the science of baking bread, what's actually happening when you mix those ingredients together? And a few tips for when things go wrong. I'm looking at you, fellow sourdough beginners. Okay, talking to Patricia Christie, chemist and baker about the science of bread baking. But before we jump into my hashtag sourdough process, problems, let's first talk about an ingredient Patricia says is essential to good bread. Yeast. Because the yeast is the biological leavening.

So what that means is that you don't want your bread to taste like hockeypox, right? Flat and nasty. Bread is supposed to be fluffy. And the fluffiness are the gas that is produced by the yeast. And so yeast is a living organism. And when it eats the sugars, just like you eat sugars, it produces carbon dioxide. And the carbon dioxide are the bubbles in the bread. So bubbles in your dough gives you light and airy bread.

Thank you, yeast. And for sourdough, for the non-bakers out there, you don't just use commercial yeast like you find in the supermarket. You cultivate wild yeast, yeast that's naturally around us. In a gooey paste, you make of flour and water. That mixture is what's called a sourdough starter or mother. I would describe a mother as the master mix of your culture, of your yeast. And so what it is, is so when you do an experiment, say in the lab, with bacteria, you have a original bacteria that you take a sample of it and you use it for your experiments.

Right. So the sourdough mother is basically the master mother. It is what is going to include all the components that are necessary to make more sourdough bread, except it's in a more concentrated version. Gotcha, gotcha, okay. So I've got my little mother. I've got my yeast. And then you have to feed it. So you put flour and water in it. What is happening in that part of the process? So flowers contain proteins and sugars. And so yeast need the sugar to divide. So that's their nutrients, right? So if you think of it, you eat, when you eat food, the reason you eat food is you need the building blocks for all of your macromolecules.

So by giving the sourdough starter, your mother load, your flour and the water, that provides all the nutrients for the yeast to be able to reproduce. and make more of it. Got it. Okay. Okay. Got it. Got it. So then you take that starter that has been recently fed, and you mix that with flour and water as your first step of, you know, kind of bread making. Yeah, you're going to take some, you're going to take a sample of the starter and use that to make your sourdough bread of the day. You still have your master mix, but you've also got your, you've got your experiment of the day. Right, right, right.

Got it. Okay. So Patty, let's say hypothetically somebody I knew was trying to make sourdough and the dough wasn't rising. Is maybe a reason for that that I'm using like this garbage bleached flour? Is that maybe the problem? I'm trying to figure it out. Or my friend is. My hypothetical friend is. Your hypothetical friend, yes. A friend who shall remain nameless. Yes. So one of the things I would ask your friend is where in your kitchen are you? raising, are you sitting the dough, right? Is it cold in your kitchen or is it warm in your kitchen? Because the yeast, just like us, like a specific temperature. And so if it's too cold, the yeast won't be growing as well as if it's, you know, the right temperature for them. So you might want to move it around a little bit and see. The other thing I would do is you might want to wrap, you know, a plastic wrap or something over top. Gotcha. Sour dough doesn't like a lot of oxygen. So it will use up the oxygen that's present. And then it will become without oxygen, which is what we call anaerobic. And that's going to give it the most carbon dioxide producing.

Gotcha. Okay. I'm going to tell you what, Patty, I was doing all of those things wrong. When you were listing them off, I was definitely putting it in a cold room. I'm definitely just covering it with little tea towel that is not preventing too much oxygen from going in there. You know what I mean? I'm a beginner, Patty. Well, you know, have you tried just the normal you know, aerobic bread recipe where you just start with yeast and add some flour and some little bit of sugar and just let it go. Are you asking me that because I'm a beginner, did I start with an easy thing that was attainable for me? Yes. Absolutely not. Absolutely not. I jumped right into sourdough. I'm like, I'm a microbiologist. I know how to make bugs grow.

Okay. So, okay, so Patty, do you have any kind of like, you know, a list of mistakes, a beginning, baker might make and, you know, what some of those things can teach us about the science of baking? Sure. The first thing that a lot of people don't do is they don't measure, if they're using dehydrated yeast, they're not measuring the temperature at which you're dissolving the yeast at the beginning. Gotcha. Right. So if you look at the package of the yeast, it says, you know, use water between, I think it's like 105 to 115 degrees Fahrenheit. And if you think of it, the reason you want to do a specific temperature is because the yeast are in a, think of it like a hibernation state. And they want to be woken up nicely, right? You don't want to poke the bear as it's sleeping. You want to just, you know, gently nudge it. So the idea is that if you use temperature that's too cold, the yeast doesn't wake up properly. If you use temperature that's too hot, you kill it. And so then you're never going to be able to get any biological leavening. So that's usually the first problem. So a good thermometer is fabulous.

And then at that point, then you can start making your dough. And the nice thing about bread is that you don't have to be gentle with it, right? It can withstand some handling. And then at that point, then you have to start making, aligning all your gluten fibers. And that's key. That's kneading, right? So kneading is really important because you align all your gluten fibers. And that gluten fibers then is going to give the texture of the bread.

And you can always tell that you've needed enough if you stick your finger in it and pull it out and your finger sort of divot stays there. And that means, you know, you've needed it enough. Gotcha. Okay. What's your best advice for people who are just getting into baking now? Find a basic recipe, make it, and see if it works. And if you can reproduce it, then you know you've got the fundamental of that experiment. And then once you feel comfortable following the recipe exactly, put some variations in and then see if you can improve upon it. It's all about practice, right? You find a good recipe, you follow it exactly, and see what the result is. Yeah. You know, I also wonder if, Patty, a piece of the advice for people starting to get into baking is to try to be patient with themselves and have fun,

Because I'll admit, you know, sourdough day six, in deep, can't get my bread to rise. I was like, do I need another thing that I cannot accomplish right now? You know what I mean? I know exactly what you mean. And it's especially important to think about, you know, this is sort of the equivalent of an extracurricular, right? This is something that you're trying to do to relax and have fun. And you need to, you know, step back a little bit and say, you know what? let's see what I can accomplish today and just, you know, take a deep breath, look at your experiment,

and see, you know what, maybe today wasn't a good day. I can try it again tomorrow. It's okay. Patty, I just want to reiterate how much I wish I had this conversation with you a week and a half ago. Well, you know, you have my email address. You can always send me a query because it's always fun to think about troubleshooting what's going on in your world. I'll tell you what, Patty, you're going to regret giving me your email because I've got a lot of questions and I've got a lot of pictures of ugly bread. I'm going to be sending your way. That's okay. I seem to have a little bit of time on my hand these days.

A big thanks to Patricia Christie, chemist and MIT lecturer for all of her good advice and emotional support. Today's episode was produced by Britt Hansen, who does not bake bread, and edited by Viet Le. The facts were checked by Emily Vaughn, who I assume is a fantastic baker. Special thanks to my partner Natalie for the kitchen audio and her unwavering support in these trying sourdough times. I'm your host, Maddie Safaya, and you're listening to Shortwave from NPR.