- There is nothing quite like chocolate.

It's delicious, soothing, sensuous, and it's had a hold on us for thousands of years.

Mm chocolate.

I'm gonna like this episode.

I'm Sheril Kirshenbaum and on this episode of Serving Up Science we'll finally figure out what all of those percentages on dark chocolate really mean.

We'll also find out what really high percentage chocolate taste like.

Okay, let's start with one of my favorite parts that's easy to overlook.

Chocolate, it literally grows on trees which means there is such a thing as a chocolate forest.

The wild cacao plant originated in what's now Ecuador before being domesticated at least 4,000 years ago and it all began with dark chocolate.

(harp music) And it comes from these, cocoa pods.

The cocoa fruit ranges tremendously in color from dark purple to orange to pale green.

The pulp can have a wide range of tastes from nutty to fruity and its seeds are bitter without the sweet chocolate notes you might expect.

All in all, picking up a cocoa pod could be a disappointing experience for anyone envisioning Willy Wonka's chocolate room.

To bring out the flavor we recognize as chocolate it takes a lot of time as well as drying and roasting.

And while it may not be obvious, chocolate is a fermented food.

Now we don't know everything about the history of making chocolate because the archeological evidence is limited.

But there are vessels dating back to 1500 BC that still have traces of chocolate inside from the Almac people who lived in what is now Central America and Southern Mexico.

Rumor has it that chocolate beverages were made for ceremonial and medicinal purposes.

Then in the late 1500s the Spanish got in on the game and brought chocolate back to Europe.

They added some sugar cane, some honey, and voila it was sweeter.

But it was only reserved for the aristocracy.

It wasn't until the 1820s that Europeans finally figured out how to press chocolate into a hard pallet leading to the first bar-like consistency.

During the 20th century, mass distribution greatly increased the popularity of milk chocolate.

And in late 20th century, dark chocolate reappeared and grew in popularity due to its health benefits.

So let's find out more about, see I don't want to say health benefits twice.

(beep) It's good for your body.

- [Woman Producer] That's good.

- Oh I wasn't really gonna say-- - [Man Producer] Do it like that with a Brooklyn accent.

(laughter) - Folks where I live don't actually talk like that but I can do it pretty well.

And I can definitely do Long Island.

(laughter) We should do some serious Long Island, have my cousins on.

(beep) And in the late 20th century, dark chocolate reappeared and grew in popularity due to its health purpose.

Joining me in the kitchen today is Barbara Wilson owner of Mindo Chocolate.

(camera shutter noise) So while I pepper Barbara with questions, we'll be eating progressively darker pieces of chocolate.

Think of it like the serious hot ones but for a bitter sweet things instead of spicy wings.

Anyway, the first thing I want to ask you is how do we define dark chocolate and what are the different percentages actually mean?

- Well dark chocolate is anything over about 50% cocoa and there is no legal definition of dark chocolate.

And the percentages mean the percentage of cocoa in the chocolate so if it's 50% chocolate then the rest is milk or sugar or whatever other ingredients the chocolate maker puts in the chocolate.

What we have here is 67% chocolate if you'd like to try some.

- Yeah let's do our low percentage which I should point out is still higher than a lot of the candy bars we find here.

That's a good one.

What do we have next?

- Oh we have a 70% but this one's our rustic chocolate so the texture is going to be very different.

- Looks different.

- It's not refined as much as the other chocolate you tasted so it has crystals in it.

- Ooh, I like the rustic.

- This one is 77%, we're back to smoother chocolate that's been stone ground for a longer time.

- All right so let's see, I'm wondering if this is gonna be a little bit bitter if I'll still like it.

Yup, I still like this one.

Let's taste our darkest chocolate.

- We have 100% chocolate here.

- Oh so when we're going dark we're going as dark as you can.

And what is dark chocolate known for?

- As far as flavor it would be fruity notes.

- It is not what I expected, I mean it wasn't that bad bordering on pretty good.

It's much smoother, not nearly as bitter as I thought it might be.

And this is where how dark chocolate is made really matters.

in the US a candy bar only legally needs to be 10% cocoa to be called chocolate and that's clearly just not going to cut it in terms of health benefits.

If you're interested in chocolates health perks, it needs to be at least 70% or 80% dark chocolate.

And since we're going darker it's worth pointing out that this is good for us.

For a long time we've known that the theobromine in chocolate can act as a stimulant but more recently scientists have spent a lot of time studying the science of chocolate and the results are a reason to be optimistic.

So when people crave really dark chocolate what are the notes or flavors that they're really going for?

- There's magnesium in chocolate and I think a lot of people crave magnesium.

- Have I mentioned this is my favorite episode so far?

Now that we've had our fair share of chocolate, let's turn to our panel of chocolate enthusiasts to see what wins them over.

First sample, this is 67% cacao and you're all gonna take a little taste and tell us what you think.

- It tastes really dark.

- [Sheril] Is it like Halloween candy?

- No.

I like Halloween candy better.

- I think my taste buds are messing with me it tastes like milk chocolate (laughs).

- [Sheril] You look like you love it!

Do you love it?

Our next dark chocolate is 77%.

- It's worse than the 67%.

- I don't like it, okay I'm sorry but it like it's sour.

- Um, it's better than the 67%.

(gasping) - [Sheril] Taste 100% cocoa.

- Mm.

- [Sheril] Really?

- I can't.

- [Sheril] Two very different reactions.

How about you Violet, did you like it?

- Mm-hm.

- [Sheril] Yeah?

- It's better than both.

- [Sheril] Really?

- That was painful to eat.

- It's not sweet and I don't like very sweet stuff.

- And the winner on this panel is-- - [Atlas And Violet] 100% dark chocolate!

- Except for me!

(upbeat music)