The secret behind the success of Starbucks's pumpkin spice latte, and other seasonal products, is less in the flavor and more in the type of marketing the company uses. (Jayne Orenstein,Julio Negron/The Washington Post)

Starbucks’ Pumpkin Spice Latte turns 13 years old this year, and it can be partially credited for the massive amount of pumpkin and pumpkin spice-flavored products on the market. America’s obsession with the flavor — and some people's hatred of it — grows with the amount of pumpkin items offered each year.

The PSL, as the latte is affectionately called, is Starbucks’s most popular seasonal beverage. More than 200 million have been sold since its inception, and Forbes estimated the company earned around $100 million in revenue from the drink alone last fall. It has a heavy social media presence, and its own verified Twitter account, @TheRealPSL.

Food manufacturers and grocery stores bet heavily that pumpkin products will help sales during the fall. At Trader Joe’s, the amount of pumpkin products has steadily increased since the grocery chain began offering them in the mid-1990s, according to a company spokesperson. This year, Trader Joe’s shelves will be stocked with more than 70 pumpkin items, up from around 60 items in 2015.

Pumpkin spice is a combination of cinnamon, clove, nutmeg, ginger and sometimes actual pumpkin. It’s a polarizing flavor, mainly because of the variety of pumpkin-spiced foods on the market each year gets a little more weird. The food news site Eater has been chronicling them in a list of “65 Pumpkin Spice Foods That Have No Business Being Pumpkin Spiced.” Liquor company Pinnacle makes a pumpkin pie flavored vodka, and at one point, Mediterranean food company Cedar’s manufactured a pumpkin spice hummus.

Still, the nostalgia surrounding the return of fall and pumpkin spice is hard to beat. Combine that with the ultimate marketing tool — the limited-time offer (LTO) — and you’ve just created a must-have product.

Tying an LTO to a season or a holiday associated with indulgence ratchets up excitement for the product too, says Brian Wansink of the Cornell University's Food & Brand Lab and author of “Slim by Design.”

“There’s a halo of enthusiasm around that product,” Wansink added, which drives consumers to purchase the product before it's gone.

Most customers buy only one, though. Despite all the hype surrounding Starbucks’ PSL, 72 percent of people only buy one latte per season, according to the market research firm NPD group.

Limited-time offers also make brands seem hip, which brings customers back in the door, and that’s great news for Starbucks whether they’re ordering the PSL or not. The study from NPD group also found that consumers spend more per visit when they buy a seasonal product.

For companies introducing a limited-time product, pumpkin spice is obvious, because it’s what consumers want as the weather turns colder. Cheerios introduced its version in a seasonal line this year, which also included strawberry for summer.

“It was really important to us to bring pumpkin spice to life in a way that would be in keeping with how consumers expect Cheerios to do flavor varieties,” Susanne Prucha, the director of marketing for Cheerios said. “We believe in real flavors and that’s why pumpkin spice Cheerios is actually made with real pumpkin puree as well as a blend of cinnamon, nutmeg and clove to deliver the spice.”

Prucha also pointed out that Cheerios hits on another food trend: “It’s also gluten free.”

More from Wonkblog:

How to never spill your coffee, according to science

Scientists have figured out what makes Indian food so delicious

Proof that Americans love pumpkin-flavored anything