Thanksgiving week, the aroma of pumpkin pie wafts throughout the land, as it has for generations. But these days, chances are the source of the smell is not actually pie.

While Starbucks, now serving its seasonal pumpkin spice latte for the ninth year, is often credited with helping popularize the flavor, pumpkin spice has spread to myriad categories.

There were 79 limited-time menu items featuring pumpkin at the top 250 restaurant chains from August through October, more than double the 37 during the same period in 2011, according to Technomic, a restaurant market research firm.

Those dishes included pumpkin bagels at Bruegger’s Bagel Bakery, pumpkin ales at microbreweries and pumpkin spice pancakes at Shoney’s.

“Pumpkin,” a New York magazine headline declared in October, “is the new bacon.”

Darren Tristano, executive vice president of Technomic, said comfort foods often influenced flavor trends.

“That familiarity and comfort feel is something that I think Americans are clinging to because the economy has been rough on many of us,” Tristano said, adding that such foods represented “a nice, simple pleasure and an affordable indulgence.”

It may not occur to a diner at McDonald’s washing down pumpkin pie with a pumpkin shake or pumpkin spice latte, but flavor trends are not cooked up by food brands alone. Companies that specialize in flavors often are the instigators.

Dianne Sansone, a flavor chemist and head of technical services at Flavor and Fragrances Specialties, based in Mahwah, N.J., said the company first developed a pumpkin spice flavor in the early 1990s for a coffee brand, well before use of the flavor became widespread. Nondisclosure agreements prohibit the company from naming customers, but its website says they include both “Fortune 100” and “middle market” companies.

Typically food brands provide a base, like unflavored ice cream or yogurt, and in a subsequent presentation Flavor and Fragrances serves company representatives samples to demonstrate how a flavor like pumpkin spice tastes in their product.

What companies end up buying is not just a recipe, but a physical product as well.

“We send out 400-pound drums of flavor that go into things like coffee and cupcakes and cookie filling,” Sansone said.

Yoplait, a General Foods brand, asked consumers on its Facebook page in 2011 for new flavor preferences, and as a result introduced Yoplait Light pumpkin pie yogurt as a seasonal flavor this year.

Elizabeth Fulmer, associate marketing manager of Yoplait, said sales of the flavor far exceeded expectations.

“We didn’t know how big it was going to be,” she said. “We did this as a little bit of an experiment this year and the response has been really exciting.”

Planters, a Kraft Foods brand, introduced pumpkin spice almonds as a seasonal flavor in 2011, the same year that Jet-Puffed marshmallows, another Kraft brand, introduced a pumpkin spice variety.

Through a licensing agreement, Unilever introduced Starbucks pumpkin spice latte ice cream as a seasonal variety this year. It is, in other words, an ice cream based on a coffee drink that was based on a pie. Another Unilever ice cream brand, Ben & Jerry’s, has marketed a seasonal pumpkin cheesecake flavor for several years.

Hiram Walker introduced pumpkin spice liqueur, a seasonal offering, in 2007, when the flavor “was popular within coffee but not as widespread as it is today,” said Juli Falkoff, a brand manager at the company, which is a Pernod Ricard USA brand. “I feel like this season it’s really pumpkin spice time – it’s everywhere you look.”