Why Weed's Signature Scent Has Changed Over Time

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You're listening to Shortwave from NPR. Hey, Shortwavers. Regina Barber here. And I love long walks. And sometimes on my walks around the city, I get some distinct smells. One of them... is cannabis. I hear you, Gina. It's that skunky, gassy smell that wafts out from doorways and windows and people's stoops. It is that unmistakable smell of weed.

Ping Wong, NPR health reporter, friend of the show. I understand you went on a journey lately to learn about why cannabis smells the way it smells. Yep, it's true. It went to the depths of Western Maryland. And today I'm going to take you along with me. We're going to a high. Hydroponic Cannabis Grow Farm, where they produce 15,000 pounds of cannabis flower each year. That is a lot of pot. That's what he said. It's a lot of weed. So who's he?

So that's Andras Kirshner. He's the founder and head grower at District Cannabis. They sell in Washington, D.C. and in Maryland. And he's going to be our tour guide today. He's going to take us around the facilities. That's our grow facility. That's our weed factory. It's a dream come true.

So this is a facility that opened in 2020, and they do a lot here. They grow baby cannabis plants to maturity. They harvest and dry them. They process and package them for retail sale. And to take the tour, we got suited up. Jacket. We should get you a lab coat. And then we're going to have to put your shoes in a little wrap to protect the plants. And Gina, you and the listeners are going to come with us. I'm excited. Let's do it.

We're going to dive into what's behind that distinctive smell of marijuana and how it's evolved to incorporate more notes of lavender and citrus and less overwhelming funk. So today on the show, we'll take you on a smell tour of a cannabis factory and talk about why weed smells the way it smells and how that knowledge is leading to more varieties. You're listening to Shortwave, the science podcast from NPR.

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Hi, it's Terry Gross, host of Fresh Air. Hey, take a break from the 24-hour news cycle with us and listen to long-form interviews with your favorite authors, actors, filmmakers, comedians, and musicians, the people making the art that nourishes us. Okay, so Ping, tell me more about this grow farm you went to in Western Maryland. So it's out in Hagerstown. It's about an hour and a half northwest of D.C. And it's just off the highway and just down the street from the sheriff's office. Okay.

And it is a big warehouse and greenhouse compound locked behind barbed wire gates. We started in the nursery where they have racks of these little plants stacked on top of each other. So young plants in the vegetative state, they like... high temperatures and humidity. So that's how we keep the environment in here. And Ping, what did it smell like at this point in the nursery?

Honestly, not a lot. I mean, when I was driving in, I got like a hint of that skunky smell. But in the first growth stages, cannabis doesn't really smell like a whole lot. Just earthy like plants growing. It's only when the plants bloom that it really starts giving off smell. And that was our next stop, the indoor flowering room. So what you're going to see in here is our famous gelato cake strain.

You are here just about five days before harvest. It's this warm, humid room with rows and rows of blooming cannabis plants, about 1,500 in all. Squeeze it a little bit, and then you get the essence in your fingers. Okay, so to back it up, last year Andras won the grand champion title in a competition with other weed growers from D.C., Maryland, and Virginia. Oh, wow. Congrats to him. Yeah, it's called the National Cannabis Championship, and he won with a strain called Lairc.

Now, the room that we're in now, it was filled with a cousin to it called Gelato Cake. It's one of their top-selling strains. And Kyle Pearl, who's the general manager of operations here, described the smell for us. So this is definitely one of our more... complex profiles. Its dominant terpenes are caryophyllene. limonene and linalool. Okay, so wait a second. What are terpenes? Okay, good question. Yes, thank you. So these are one of several types of chemical compounds that are in

cannabis. These terpenes in particular are chemical compounds that are found in a lot of plants, from herbs and citrus to pine trees. And in cannabis, they're largely responsible for the different smells and flavors in the plants. Now, with gelato cake, those terpenes were giving sweetness and grapes with some cognac on the finish. Wow. That was their description. It smelled a little floral, a little hoppy to me. Okay.

And it had some notes of kerosene as well, or as Andras calls it, gas. It was what a lot of the breeders wanted when they started breeding cannabis. And so a lot of the strains started to really exhibit that skunk smell.

Right, that skunk smell, like that classic smell of wheat. And I spoke with Pamela Dalton, who's a smell scientist at the Minnell Chemical Census Center, which is this nonprofit research institute. They focus on smell and taste. And she says that that classic weed smell used to be attributed to a skunky terpene, but more recently, researchers found a different culprit. Oh. And they found out that it was actually a sulfur compound, which...

to my way of thinking, would absolutely be what would be responsible for a sulfur odor, right? The smell of skunk spray or anything like that. She says it's that sulfur compound mixed with the fresher-smelling terpenes that gives marijuana its signature smells. And in some strains, that skunk note really dominates. we are extremely sensitive to sulfur compounds. So if you have a range of compounds in your cannabis, it's likely that what you're going to smell first are the sulfur compounds.

Wow, that's like really fascinating. So like even if there's just a little bit of that sulfur, our noses are so sensitive that it's going to like be the main thing they smell. That's right.

But Pamela says that there's been a trend in cannabis cultivation towards new strains and hybrids that are more pleasant to more people. I'm almost 70 years old, and the cannabis I smelled when I was... 13, 14, 15 smelled way skunkier than anything that I experience now. And Andras, our cannabis farmer, has seen this too.

He says that in the early days, cannabis breeders and growers were really going for that skunk smell. But in more recent years, as recreational use has grown, cannabis breeders and growers are developing new strains. And there's been a blossoming of varieties with more smells. flavors. From berry to citrus, lemon, lime, cherry, and a lot of the... Popular strains are kind of a combination between the gas and another flavor.

I mean, lemon, lime, cherry, citrus, it all sounds a lot like candy. That's true. And in fact, Jamila Hogan, who goes by Jay Mills, she's a longtime weed educator, head of a cannabis experience company called Abadie Green. she says that all these varieties have been trending in the same direction. It's the runt sticky cake gelato profile. You know it because the buds are oftentimes a little bit purple, super frosty.

Those buds are coated in these tiny glands that produce resin and kind of sparkle in the light. She calls the whole lineage runcicacolato. The nose on it is musky, gassy, sweet. and skunk. I like to call it the bad girl after brunch smell. Tell me a little bit more what she means by that. I had the same question. I was like, say more. She's sweet, but she's funky. She needs to take a shower. But it's a good sweet funk. She had a good time.

J. Mills says that this cakey gelato profile has been dominating for the past five or six years. Before cake, it was cookies. Before cookies, it was gas. But back at the growth farm, we're going from room to room through the production process. Kyle, that general manager, he pointed out a strain called pave, which is named after super sparkly jewelry. It was flowering in the greenhouse. It's an overwhelmingly kind of cushy... It's almost a little minty, a little spearminty.

There are stalks of cherry limeade cake that were hanging upside down to dry in the cure room. In the trim room, Andras says that they are processing a new hybrid called Berry-Payton. It is a tropical runts times Gary-Payton. Those are the parents. You can definitely smell the fruity profile. Did you smell it?

I mean, I smelled all these different rooms. Like, literally every room smelled a little bit different. I wish you could smell it. It was like a different combination of musky, fruity gas. Okay, so Pink, nobody buys cannabis just for the smell, right? It's true. Yes.

That is a fact. The main reason people buy cannabis is for its psychoactive properties, to get high or to relax or to treat a medical condition. And that comes from a whole other class of chemicals like cannabinoids. Okay. And marijuana is big business. a national survey from 2022 that showed that people in the U.S. are now using cannabis more regularly than alcohol. Wow. This room's going to be a little loud. We've got a lot of machines firing off in this space.

So the weed grown here is headed for the local market, and Andras says that some of it gets packaged and sold as flour, or extracted for edibles and dabs and vapes, or pre-rolled into joints. So we have a machine here that is automated and can make four million pre-rolls in a year. We're currently not selling that many, but we can make them.

And in Maryland, where cannabis has been allowed for recreational use since 2023, consumers have spent more than $180 million on cannabis products in the first two months of the year. So clearly there's a lot of demand for this. Ping, thank you so much for bringing this reporting. I had a great time. Thanks so much. Me too. This episode was produced by Rachel Carlson. It was edited by showrunner Rebecca Ramirez and fact-checked by Ping Wong and Tyler Jones. Kweisi Lee was the audio engineer.

Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Shorewave from NPR. These days, there is a lot of news. It can be hard to keep up with what it means for you, your family, and your community. Consider This from NPR as a podcast that helps you make sense of the news. Hola, it's Sarah Gonzalez.

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