The sun is still blazing, summer holidays aren’t quite over, and yet autumn has already arrived - well in cup form at least.
Starbucks officially launched its Pumpkin Spice Latte this week, marking the unofficial start of autumn on coffee shop menus. Since its debut in 2003, the Pumpkin Spice Latte (also known as the PSL) has become a commercial juggernaut, with hundreds of millions sold and an entire pumpkin-spice industry springing up in its wake.
Competitors rushed to join in: Dunkin’ introduced its own pumpkin drinks in 2007, while McDonald’s followed with a PSL of its own in 2013.
But what explains our enduring obsession with this beverage?
The flavour chemistry
The drink's key ingredients are espresso, pumpkin spice flavour sauce, steamed milk, topped with whipped cream and a spice blend of cinnamon, ginger, nutmeg and cloves. Behind that taste lies a unique combination of chemical compounds that don’t just deliver flavour, but physical sensations.
“The chemistry of the spices that go into pumpkin spice is just amazing,” said Dr. Steve Talcott, professor of food chemistry at Texas A&M University.
“We have these wonderful natural compounds like clove. We have a compound called eugenol, which is a terpene. It’s very cooling, and a cooling sensation in your mouth. So you get this warm feeling in your body as your mouth is being cooled off”.
Cinnamon brings cinnamaldehyde, delivering that spicy bite that feels both warming and seasonal. Nutmeg contributes myristicin, which adds sweet, earthy depth, while ginger provides gingerols, compounds that activate the same receptors as chilli peppers, giving the latte a subtle heat.
Nostalgia in a cup
The draw isn’t just chemical - it’s psychological. Our sense of smell is directly linked to the brain’s memory and emotion centres. When we catch a whiff of cinnamon, nutmeg, or clove, the brain instantly retrieves associations of autumn holidays, family gatherings, and cosy kitchens.
Neuroscientists call this the “Proust effect” - when smells evoke particularly vivid emotional memories.
This nostalgic pull is amplified by scarcity: the PSL only appears for a few months each year. Limited-time exclusivity activates the brain’s reward pathways, making the drink feel even more desirable.
"If you think about getting a pumpkin spice latte in the fall, it's probably a special occasion for you," said Talcott.
"Eating a fresh pumpkin pie or fresh homemade cinnamon rolls brings a bit of nostalgia back to your life. So it's a very comforting aroma. It's a very comforting taste," he added.
Health benefits (and bittersweet caveats)
Beyond taste and nostalgia, the spices themselves pack a surprising punch of health benefits.
“There are many polyphenols,” Talcott noted. “Those compounds are natural antioxidants, as well as terpenes, these flavour compounds that also have known health benefits".
"So these health benefits could be everywhere from cardiovascular health to lowering inflammation to even improving our cognitive health,” he added
Spices like cinnamon, clove, and ginger have been shown to reduce inflammation, aid digestion, and deliver antioxidant effects.
“You may find that you maybe have a little serotonin boost after you drink a latte that has pumpkin spice in it, because it’s just firing up all the neurons in your brain and giving you this massive mental stimulation that goes along with the caffeine in coffee,” Talcott said.
Despite these benefits, it's important to stress that the PSL should not be considered a "health drink". A grande-sized cup at Starbucks contains around 390 calories and 50 grams of sugar - that's more than a can of Coca-Cola and nearly 13 teaspoons of sugar.
So delicious though they are, it's recommended that PSLs are best enjoyed as an occasional seasonal treat - though for a few fleeting weeks each year, who’s really counting?
