Loren in the Givaudan laboratory, New York City. Photograph: Gary Wayne Gilbert

Trudi Siegmann Loren’s worst enemy is a head cold. The smell of microwaved popcorn ruins her day. Scented beauty products and garlic are also off-limits for this fragrance designer, who is the “nose” behind a bouquet of best-selling perfumes including Donna Karan’s Black Cashmere and Tommy Hilfiger’s Dreaming. “My daily life is purposely unscented,” says Loren, who keeps track of up to 30 fragrances in different stages of creation.

Loren is vice president for corporate fragrance development worldwide at the Estée Lauder Companies. She helps clothing designers and even car makers (Mustang) with whom Estée Lauder has licensing agreements translate marketing concepts into olfactory offerings. “The marketing team paints the picture with words,” she says, “and I paint it with scent.” (For Black Cashmere, the stress is on “scent with soul”; for Dreaming, “the sensation of falling in love.”)

A biochemistry major, Loren learned the language of scent during a three-year apprenticeship at a French-owned fragrance company, where she started out as an analytical chemist. “You begin by smelling individual raw materials,” she says, “all the citrus, all the flowers, all the woods”; a perfumer must be able to differentiate at least 2,000 fragrances, natural and synthetic—from bergamot to frankincense—and learn how to combine them.

On a drizzly March afternoon, Loren, tall, slender, and chic in a short belted black trench coat, strides briskly a couple of blocks south from her office in midtown Manhattan to the U.S. headquarters of Givaudan, a Swiss multinational fragrance and flavoring company. The company is vying to develop a new fragrance for one of Loren’s clients.

In a conference room, Loren delicately inhales the scents on a succession of six-inch-long white card strips, moving deliberately yet crisply through blends with working titles like “Fast Pussycat,” “Empress,” and “Fast and Fabulous.” She delivers her verdicts with a fluency and decisiveness born of 20 years in the trade and in its native tongue. “What I am smelling would be a very interesting heart and back,” she says of one blend of amber, iris, Madonna lily, plum, and incense, “but we go right into it too fast.” She leaves the developers with instructions: “There needs to be much more of a floral, sparkling introduction.”

Outside, the light rain has intensified the signature fragrance of a New York street: sugar-coated peanuts, slightly burned, with a background hint of pretzel.

Jane Whitehead is a writer in the Boston area. Luke Jorgensen’s interview with Tom McCarthy may be viewed in its entirety at www.bc.edu/frontrow.

Read more by Jane Whitehead