There probably are very few people eating chestnuts roasted on an open fire during the holiday season, but anyone who has walked — even just once — down Manhattan’s Fifth Avenue at Christmastime likely has a pleasant association with that warm, nutty smell.

You might also feel that way about a whiff of vanilla, cinnamon, pumpkin pie or gingerbread. There’s also the ever-popular scent of a fresh-cut tree.

Warm up the home

They’re the smells of Christmas, filling the air. And they’re an easy way to make your home feel instantly warm and holiday-ready.

“Home fragrance is decorating every time you do it,” says home-fragrance guru Harry Slatkin. “Fragrance is key to setting the mood. You can even choose a cheap wine to serve to your guests if your home smells delicious.”

You can scent your home from scratch — get out those cookie sheets — or get help from dozens of commercial products such as candles, potpourris, sprays or plug-ins.

Layering scents

Use several complementary scents at the same time, Slatkin recommends.

“It’s the only way to smell the scent,” Slatkin says, “otherwise you get too used to it. It’s olfactory desensitivity. Different scents awaken your nose.”

But layering can be complicated, he warns, as you don’t want your nose to be jarred as you move from room to room. He recommends using vanilla as a base — it goes with everything.

Some scents may be more personal and born of individual family traditions.

Scent marketer C. Russell Brumfield remembers knowing it was the holidays when he could smell fudge and peppermint. He also associates popcorn with Christmas because his family would string it on the tree. But with fewer people doing that, today’s teenagers are more likely to link popcorn to the multiplex.

The memory connection

Scent has a well-documented link with memory, and it might be more noticeable this time of year because scent memories are largely formed during childhood.

Think about how music might have helped shape your teen years and a few lyrics can remind you of a high-school event, says Brumfield, who wrote “Whiff: The Revolution of Scent Communication in the Information Age” (Quimby Press). The same thing happens via smell when you recall your favorite days between the ages 1-11.

“The other four senses are wired to the left brain, so we think about those things before we link emotion,” Brumfield says. “Scent is on the right side. There’s no thinking, it just affects our emotions.”

We’re drawn to “comfort smells,” he adds, which are like “a tattoo on your mind — they make a lasting impression.”