The creator of Starbucks' famous Pumpkin Spice Latte said it almost had a very different name

• Starbucks' Pumpkin Spice Latte almost had a very different name. 
• Peter Dukes, the "Father of the PSL," told Insider it was almost called the Fall Harvest Latte. 
• Starbucks also considered calling it the Pumpkin Brulée Latte. 

Starbucks' Pumpkin Spice Latte has become as synonymous with fall as cardigan sweaters and "When Harry Met Sally" rewatches.  

But the PSL was almost named something else. 

Insider recently sat down with Peter Dukes, the "Father of the PSL," to celebrate the famous drink's 20th anniversary and learn more about its origin story. 

Dukes and his team began brainstorming a new Starbucks fall drink following the peppermint mocha's successful debut during the 2002 holiday season.

They came up with 100 ideas at the "Liquid Lab" — the former name of Starbucks' research and development space at its Seattle headquarters — and eventually narrowed that list down to four flavors, which they developed into drinks with the help of Starbucks' food scientists. 

"There was a lot of debate about what the fourth flavor was going to be, and pumpkin was in that debate," Dukes said. "Go back 20 years. If you walked down the grocery aisle, there were only two things that were pumpkin — pumpkin purée and pumpkin-pie topping. Nothing else existed out there. There were no pumpkin beverages that existed." 

Dukes and his team decided it was a risk worth taking, and helped develop the Pumpkin Spice Latte's flavor by pouring espresso shots over pumpkin pies. 

"We knew we had something that was pretty unique," he added. "And the rest from there is history." 

But before the PSL could go to market, it needed a name. And Dukes said there was a lot of debate. 

The Starbucks team considered calling it the Fall Harvest Latte to pay tribute to the season — but realized customers would have no idea what the drink actually tastes like.  

Another option was the Pumpkin Brulée Latte, but the team wanted to focus on the other ingredients in the drink as well. 

"The spices were really important — the nutmeg, the cardamom, the cinnamon all play an important role in drawing out the best pieces of the espresso," Dukes said. "So we landed on Pumpkin Spice Latte." 

The PSL was an instant hint, and Dukes, who still works at Starbucks, said it's been incredible to watch the Pumpkin Spice Latte continue to grow in popularity.

"Fall is my favorite time of year. I love how the leaves are changing colors. It's that time you're getting back into your rhythm and routine," he said. "And the Pumpkin Spice Latte helps capture that in a cup a little bit — it brings a smile to my face."