Experts say pumpkin spice seasoning involves some “incredible chemistry” that can produce a nostalgic aroma as well as a comfortable feeling.

You can order a pumpkin spice latte just about any way you want.

With skim milk, soy milk, almond milk, or more.

You can order it iced or extra hot.

You can order it with whipped cream or without.

But no matter how you order it, each glass also comes served up with a heaping dose of feel-good nostalgia.

“They taste like warm-blanket feels,” said Joanna Wheeler Johnson, a school psychologist in Georgia.

“It’s really the smell, not the flavor that I love,” added Chelsea Henshaw of Mississippi. “I always buy at least one pumpkin spice latte at the beginning of autumn weather. Then, I remember that I don’t actually like the super sweet taste.”

The pumpkin-spiced craze is about 15 years old and has seen an acceleration in popularity since its earliest days.

In 2003, Starbucks introduced their famous PSL, which now has its own verified Instagram and Twitter accounts.

“Nobody knew back then what it would grow to be,” said Peter Dukes, the Starbucks product manager who led the development of the pumpkin spice latte, in a statement before the 2017 pumpkin spice latte return. “It’s taken on a life of its own.”

Before the coffeehouse conglomerate introduced their famous fall concoction, the seasonal scent was primarily used for candles and home fragrances.

Now, however, pumpkin spice flavorings are in almost every type of food you could imagine, from Cheerios to Oreos, pancake mixes, and protein bars.

If you think this pumpkin spiced insanity is a prime example of marketing done well, you might be correct.

But there’s also some science to explain why we’re all lining up around the corner the day Starbucks drops their first cup of PSL.

Pumpkin spice mixes are typically a combination of cinnamon, nutmeg, ginger, and clove or allspice, said Dr. Kantha Shelke, a food science communicator with the Institute of Food Technologists and an adjunct faculty member at Johns Hopkins University in Maryland.

“Spices alone do not create the ‘pumpkin spice latte’ magic,” Shelke told Healthline. “The popular and almost addictive taste and aroma develops only when these spices are cooked or baked with pumpkin, cream, butter, and sugar. It is this flavor combination that companies have replicated in the popular pumpkin spice latte using extracts and flavors. Pumpkin spice products don’t contain pumpkin or even just these spices. There is some incredible chemistry behind it.”

There’s also the emotional aspect of it, Shelke said.

Companies know people pay for comfort and nostalgia in food, and they’re more than happy to deliver it in the form of pumpkin spiced goods.

“The human brain is adept at identifying aromas quickly in terms of when they were last encountered. In Western culture, the aroma of a baking pumpkin pie immediately transports people to all the warm and friendly times associated with pumpkin pie — holiday gatherings, families, celebrations, treats, sweets, things that childhood memories are made of,” Shelke explained.

Kristen Hovet, a Vancouver-based science journalist and yoga instructor, said the addictive nature of pumpkin spice also goes to a biological reaction we have when we eat these foods.

Hovet learned during yoga teacher training, including some courses on Ayurveda (a holistic healing approach), that pumpkin-spiced products come with many healthful ingredients.

“These four main pumpkin spice ingredients [cinnamon, nutmeg, ginger, and cloves] all have warming properties and increase circulation,” Hovet told Healthline. “This is perfect for cooler or cold weather, when our circulation slows down. A reduced flow of oxygen can make you feel tired and lethargic, but after having a pumpkin spice latte or another pumpkin-spice flavored food or beverage, our blood vessels expand and we feel warmer and more energized.”

It’s this pleasure sensation, as well as the memories the flavors evoke, that have us reaching for every pumpkin-spiced food we can find, Shelke says.

“Seasonality helps. The warmth of the mixture is an ideal comfort during cooler weather,” Shelke said. “Being warm and happier — and therefore, nicer and more giving — especially during the holidays makes pumpkin spice as effective as juniper and pine in fireplaces in changing our frame of mind and soothing us. Optimized spirits can be uplifting and foster a feeling of wellness, and this can make people crave it repeatedly.”

That, and sometimes these foods really are just plain tasty.

If you don’t have the five bucks to offer the green apron-clad baristas, that’s OK.

Hovet offers a few ideas for enjoying the benefits of the spices without shelling out major cash.

“I am celiac and love putting pumpkin spice into gluten-free oatmeal on cold mornings,” she said. “Another favorite is pumpkin spice cookies made with brown rice flour and canned pumpkin.”

Not a fan of the pumpkin spice combination, but enjoy the spicy comfort in warm beverages? You’re in luck.

Several other foods and spice combinations offer the same feel-good benefits and they’re equally flavorful.

Chai would be very similar in that it is black tea often mixed with the main ingredients of pumpkin spice plus cardamom,” Hovet said. “Cardamom, in addition to having warming properties itself, is excellent for relieving gas and bloating. You can see that many of these blends share certain commonalities. They are warming, increase circulation, and aid digestion.”

Shelke adds that the mixture of spices for Middle Eastern baklava and the cinnamon-nutmeg mix in rice puddings evoke many of the same intense emotions as pumpkin spice.

“The caramelizing notes of burning sugar can be soothing for many, for it reminds them of childhood days and mom baking cookies,” Shelke added. “When sugar is heated, it forms a vast number of aromatic compounds that can transport people through a range of experiences beyond cookies.”