It's easily the world's most expensive spice.

The next most expensive spice?

Vanilla at about $600 a pound.

So, what makes saffron so wildly expensive?

For starters, saffron is a complicated spice to harvest.

My name is Arash Ghalehgolabbehbahani. I am a post-doctoral research associate at the University of Vermont.

To harvest the saffron, you need a lot of hand work to pick up the flowers, separate — saffron is the dehydrated or dry stigma.

The stigma is the female part of the flower. You have to separate the stigma, dry that, and for all of these procedures, you need hand works, laborers.

I prefer to harvest the flowers by hand because I don't like to damage the other parts of the plants.

Saffron comes from the Saffron Crocus flower, and each flower has three red stigmas.

That's the saffron.

The yield of saffron is really low. You know, you have to hire a lot of laborers to harvest 4 pounds of saffron per acre. That's nothing.

Just one pound of saffron requires 170,000 flowers.

The purple flowers bloom over a six week period from late September to early December.

There's also a specific time of day to harvest them.

When we have a higher relative humidity in the air, it can affect the saffron quality.

Also, sunlight can break the chemical structure in the saffron.

So, we prefer to harvest the saffron early morning every day, or, if you don't have flowers every day, every two days.

90% of the world's saffron is grown in arid fields in Iran.

But harvesting all that saffron comes at a price.

Why is Iran the main producer of saffron? Because workers are available and they are cheap.

In some parts, it's like slavery, their behavior with laborers. I hate that, I should say.

Based on my experience, you know, they usually, the workers came to farms in Iran around 5,6 a.m. and they left around 4 p.m.

Most saffron harvesters are women, getting paid a maximum of five dollars a day.

Saffron is not only grown in Iran.

It's grown in Morocco, Spain, Italy, the Netherlands, Afghanistan, India, and even in the United States.

Why the US?

Though many Americans have never eaten saffron, the US imported 25 tons in 2013 and 46 tons in 2016.

I knew that saffron has a good resistance to the cold weather. If you cover Vermont state with a layer of plastic, you will have the same situation that we have in Iran.

What's so great about saffron?

Over centuries, it's proven useful in many situations.

Saffron is most commonly used in cooking.

As an Iranian, every day we use saffron in our dishes, you know. We cook with saffron a lot. So far, I cannot find an alternative for the taste of saffron.

It gives paella its signature flavor and golden color.

It's also used in broths, breads, and marinades.

When saffron is broken down, it creates a golden dye.

Everything is not just about saffron production procedures.

Saffron contains some chemical components, which are really expensive, like picrocrocin, crocin, and safranal.

They are three main components or compounds, which are responsible for the taste and color and smell of saffron.

When we are talking about saffron quality, technically we're talking about these three chemical components. Saffron, inherently, is a valuable thing.

People have tried passing turmeric, red marigold petals, and lily flower stigmas as saffron.

But the flavor and dye is totally different.

In large quantities, saffron can be a potent, happiness-inducing narcotic.

And research suggests, it may help reduce the symptoms for Alzheimer's, depression, and PMS.

Who knew this little spice packed such a punch?