(light music) - All I really wanted to do in this video is eat delicious tacos.

Mm, oh my god, that is good.

And don't get me wrong, I did that, but I also discovered something ancient and profound that changed the way I see pretty much all of this and also all of Western civilization.

But let's start where I started, with tacos.

Now, if you make tacos at home, you probably use these.

(air whooshing) And look, these are fine.

They're fine.

(light music) (air whooshing) But some restaurants and fancy home chefs make their own tortillas from scratch using this stuff.

Masa harina, just add water, knead, press, and pan fry some fresh tortillas, much better.

Now here's where things get controversial.

These tortillas, we can all agree that they're not really from scratch, right?

Some people claim that making tortillas truly from scratch, from dried corn kernels, which involves cooking and soaking the corn for six to 18 hours in a roughly 1% calcium hydroxide solution to achieve the perfect softness, grinding the corn to the perfect consistency, forming perfectly shaped tortillas, and finally, pan frying them, some people claim that this is the only way to go.

Other people prefer masa harina, or at least they prefer the convenience and argue that there isn't much of a difference in taste.

When I first heard about this debate, I thought, "This will be the video."

But then, I discovered the thing that is actually gonna be the video.

(light music continues) (bell ringing) Oh, no.

First, corn.

We know from biology that corn is a type of grass, not this kind, but this kind.

If you've ever tried to eat grass, which I don't recommend, you'll notice that it passes right through you, pretty much unchanged.

Which means you're not extracting much, if any, energy from it.

Mesoamericans who lived in what is now Mexico and Central America and wanted a more energy-dense food source probably noticed this as well.

So, they started to selectively breed the plant, setting us along a path that would transform this into this into this, which today is one of the three most grown crops in the world.

But selective breeding wasn't the only obstacle the Mesoamericans had to overcome.

They also needed to figure out how to eat the corn.

Corn's ancient ancestors and even modern-day field corn are not like grocery store sweet corn.

You cannot just eat it raw.

The kernels are hard and dense and basically indigestible, and boiling the kernels in plain water doesn't do much.

But if you boil them in a roughly 1% calcium hydroxide solution, chemistry happens.

Suppose you died tomorrow.

(glove slapping) Sorry.

You could choose to be cremated using a process called alkaline hydrolysis.

A crematorium would put your body inside basically a very large pressure cooker and fill it up with a 5% potassium or sodium hydroxide solution.

They'd heat you up to a few hundred degrees and give you a stir.

Three to 16 hours later, your entire body, except for your bones, would be completely dissolved.

Oh.

(laughing) This works because so many of the molecules in your body are polymers, long chains of sugars or nucleic acids or amino acids.

The individual units tend to be held together by ester-type linkages, which in a protein, are called amide or amid bonds and look like this.

So, what happens when you add a strong base like hydroxide?

Strap in, 'cause this is gonna be a year of organic chemistry is about 15 seconds.

The electrons on the hydroxide nucleophilically attack this electron-deficient carbon, which kicks these electrons up to this oxygen, forming this unstable intermediate.

Then the electrons come back down, reforming that double bond, and pushing these electrons away, forming this wildly unstable azide ion, which immediately grabs a hydrogen from here.

And then, you have two molecules where before you had one.

Do this enough times and pretty soon, a stubborn, hard, chewy polymer that was hundreds or thousands of subunits long becomes a bunch of small molecules that dissolve super easily in water.

Mesoamericans were not interested in cremating corn, but cooking corn in an alkaline solution, partially hydrolyzing it, has a similar, if less severe, result.

The corn gets softer and mushier.

It's easier to grind, which means it's easier to eat, which means it's more digestible.

That last bit was important for all of Western civilization.

And we'll get back to that later, I promise.

But first.

(kernels clinking) (playful music) (whisk scraping) First, I'll cook the corn in a roughly 1% solution of food grade calcium hydroxide at roughly 95 degrees C for about 1/2 an hour.

Then, I'll let the mixture sit overnight.

And as you can see, the corn is completely transformed.

The color is a lot deeper.

The kernel is a lot larger.

And probably of most interest to the Mesoamericans, the kernel is much softer.

Then I'll drain the liquid away and rinse the corn.

Now, rinsing does two things.

It removes any excess calcium hydroxide and it also starts to remove some of the kernel's outer shell called the pericarp.

You can remove more of this if you want by manually (mimics liquid sloshing) ing the corn.

Next, I'll grind the kernels.

(speaking in a foreign language), not the right tool for the job, but it's what I got.

(playful music continues) These days, there are much faster methods than what I'm doing here.

(playful music continues) Then, I'll knead the resulting dough, form it into little balls, press the balls, cook the resulting tortillas, and then, I'll have the perfect vehicle for taco fillings.

Not bad.

Five outta 10.

Just because I don't think we ground it finely enough.

Try it, good flavor.

- Really good flavor.

- Yeah.

Now, I don't know if you've noticed, but this is a (beep) of work and takes almost 24 hours start to finish.

(light music) You might be lucky enough to live close to a taqueria like Taqueria Picoso in Alexandria, Virginia, that does this whole process from scratch.

The alkaline hydrolysis, the steeping, the rinsing, the grinding, the kneading, the forming.

But as you can see, making tortillas from scratch requires a ton of space, some specialized equipment, and lots of time.

And most restaurants don't have those things.

If you don't have the space, say 'cause your kitchen has to fit into a D.C. sized restaurant space, like the Michelin bib gourmand Taqueria Habanero, you can use masa harina or dry masa flour.

Just mix it with water, form the tortillas, and cook.

By the way, this actually isn't all that easy.

Juanita's just making it look easy.

(light music continues) Ah, okay, and then like this.

Oh no, I messed it up, no, I messed it up.

(buzzer ringing) Ah no.

(laughing) - [Speaker] There's no ripping.

- It's hard.

Don't screw it up.

Oh.

(buzzer ringing) (laughing) Was there a difference in taste between Picoso and Habanero's tortillas?

I couldn't taste the difference, but A, I didn't taste them side by side, and B, I can't taste the difference between brined and unbrined chicken.

Seriously, we made an entire reactions video because of my underdeveloped taste buds.

Anyway, Andrew claims he could taste the difference, though he did say it was pretty subtle.

To me, both were delicious, though that might actually be because both of these restaurants use a relatively artisanal small batch producer of corn and masa harina called Masienda.

And in case you're wondering, no, they did not sponsor this video nor send us any of this stuff.

We bought it all with our sweet, sweet YouTube ad revenue.

Anyway, the best-selling brand of masa harina is not Masienda, but Maseca.

So let's make tortillas from both of these.

Maseca costs $1 a pound.

Masienda's masa harina costs $4 a pound.

Why the difference?

There's the usual reasons when you're comparing a large industrial producer to a small batch artisanal shop, and there's at least one reason that's pretty specific to the chemistry of the production processes.

Now, we don't know this for sure, but we can speculate based on the original patent for making Maseca that one reason for the reduced cost is that they don't nixtamalize the corn for very long.

Now, in traditional recipes, remember that after turning off the heat, you let the corn steep overnight.

The company that makes Maseca skips that step.

Okay, despite my crappy taste buds, can I taste the difference between Masienda- and Maseca-made tortillas?

Let's find out.

So this is Masienda.

Delicious.

Now Maseca.

No, I cannot tell the difference.

- There is a difference there, though.

This does have a little bit more flavor to it.

- Either way, I would eat either of these over grocery store tortillas.

I can clearly tell the difference.

Ah, now where was I going with this?

Oh right, yes.

Allow me to introduce you to the corn superhighway.

Now, this center line, this is the heart of it all.

And in addition to making tortillas, it's also used to make pozole, atole, tamales, and lots of other stuff.

Now, if you take tortillas, cut them up and fry them, you get tortilla chips.

If you split off from this center line earlier, right after grinding, and dry the resulting flour, you get Maseca and all of its cousins.

If, instead of drying the dough, you run it through an extruder, you get corn chips.

And if you split off even earlier, before grinding, and you deep fry that nixtamalized corn, you get corn nuts.

Corn nuts.

If you choose not to nixtamalize the corn, you could build a whole other flow chart that would take you to cornmeal, cornstarch, corn syrup, corn ffffth-oil, and all kinds of other corn stuff you use every day.

Look at this thing.

When Christopher Columbus claimed all of America for Spain, among the most valuable things he stole and brought back to Europe was corn.

But crucially, he did not steal nixtamalization, which is a bit like stealing a grenade but neglecting to steal the pin.

Pretty soon, the grenade will explode.

Can we cut to the 1700s please?

(classical music) Thank you.

So, corn has really taken root everywhere in Europe as a fast-growing, high-yield crop.

People, especially those who cannot afford a more balanced diet, are relying on it more and more as their primary source of calories.

But then, over the next 200-ish years, hundreds of thousands of Europeans at least come down with a disease the Italians call pellagra, for sour skin.

And the cause is a mystery.

Turns out the cause is this.

Now, imagine these wavy lines are hemicellulose in a kernel of corn.

Hemicellulose is a sugar polymer that's found in lots of plant cell walls.

Now, this little guy is niacin, also known as vitamin B3.

Now, vitamin B3 is an essential vitamin.

You need it to survive.

And there is plenty of it in corn, 3 1/2 milligrams per 100 grams of corn, which means you could get all the niacin you need in theory if you ate about 1/2 a kilogram of corn a day.

Two problems, though.

One, the niacin is covalently bonded to the hemicellulose, and two, it's mostly locked away behind the hard and waxy pericarp.

This is two layers of indigestible, which means that the niacin in corn is mostly useless.

Nixtamalization both softens the pericarp and releases niacin, making it available for your body to absorb.

And this is borne out by the fact that despite relying heavily on corn as a food staple for thousands of years, Mesoamericans never developed pellagra.

Nixtamalized corn is also high in calcium, thank you calcium hydroxide, and it's less susceptible to fungal contamination, but that's a whole other video.

Nixtamalization is the birth of the corn superhighway.

It allowed the Mesoamericans to subsist off mostly corn, which in turn allowed Columbus to steal the corn, which allowed corn to spread to the point where 20-ish percent of all calories consumed globally come from corn.

And by the way, if you think you don't eat corn, you are wrong.

You probably eat something with high fructose corn syrup or cornstarch or cornmeal.

Even if all you eat is, say, beef, in the US, that beef is mostly corn-fed.

So, most of the carbon atoms in your burger actually come from corn.

I think there's a good case to be made that when you look at the list of reasons that there are now over eight billion people living on this planet, nixtamalization is right up there with the invention of fire and the domestication of rice.

In case you're wondering, the tacos were absolutely fantastic.

I mean, really amazing.

Habanero makes this one with grasshoppers.

Don't knock it until you try it.

And the al pastor and the lengua tacos at Picoso, oh my.