Scents and Sensibility


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“Smell is a potent wizard that transports you across thousands of miles and all the years you have lived.”

—Helen Keller

The sense of smell is both primitive and powerful. Our ability to smell is estimated to be 10,000 times more sensitive than taste, and we can detect a scent at extremely low concentrations — a mere hint of a whiff is enough to catch our attention. A scent travels chemical pathways to a section of the brain called the limbic system, which is connected to memory and emotion.

Whenever we inhale, scented molecules come drifting into our noses. High in the nasal cavity they meet olfactory receptors, which are long, thin cells that line the inner nose. These cells have delicate hairs with nerve endings and are connected by nerve fibers to the smell center, or olfactory bulb, in the brain. Every breath we take passes over these olfactory receptors, and when we breathe deeply, they surge into action, firing off messages. Unlike other sense organs, the nose sends its information directly to the brain.

Diane Ackerman, author of A Natural History of the Senses (Vintage Books, 1990), describes the limbic system as “a mysterious, ancient and intensely emotional section of our brain in which we feel, lust and invent.”

Some fragrances cause the limbic system to gear up the glands to stimulate hormone production, which controls sex and appetite as well as other bodily activities. Among insects and animals throughout nature, scenting ability conveys basic information related to survival in a primitive world — such as recognizing friend from foe and signaling sexual readiness.

And among garden plants, fragrance plays its role in the biological dance, attracting pollinators, repelling predators and advertising for the flower its fertility, availability and the certain lure of nectar within. Scent seems intertwined with basic urges and biological evolution throughout the natural world. Though a happy coincidence, the enjoyment we humans gain from the fragrance of an herb garden on a warm afternoon is irrelevant to the flowers.


“A smell can be overwhelmingly nostalgic because it triggers powerful images and emotions before we have time to edit them.”

—Diane Ackerman

In order for any substance to emit a fragrance, it must be volatile enough to be carried off on an air current. In flowers, leaves, branches, seeds, bark and even roots, the source of the fragrance is the essential oil, which evaporates and disperses in the warm air. An herb leaf, under the extreme close-up of an electron microscope, shows bulging sacs of oil on the surface, while some of the oil sacs have broken open and spilled their load to the air.

More than 3,000 different oils have been identified from at least 87 families of plants, so there’s no question that any garden is a fragrance hub. This array is not more than the average nose can handle; humans are capable of detecting 10,000 different scents.

We can use these natural scents in so many ways, beyond the enjoyment of the moment. The physiological effects of fragrance can help us energize or relax, ease stress and anxiety, improve concentration, even ease headaches or give us sweet dreams.

Fragrance also makes a major contribution to the taste of food, as much of what you think you taste you actually smell. The thousands of taste buds in your mouth can detect only sweet, sour, salty and bitter, leaving it to the nose to pick up every other nuance in food’s rainbow of flavor. Aroma is a big part of what makes the flavor of many foods so distinctive. That’s why when you have a cold or a congested nose, you tend to lose your appetite; food doesn’t taste as good if you can’t enjoy the aroma that comes with it.


Our ability to smell is estimated to be 10,000 times more sensitive than taste.

“Smell is a potent wizard that transports you across thousands of miles and all the years you have lived,” wrote Helen Keller, an inspiring blind and deaf author.

Scent and memory are linked, and not only because of where they connect in the brain. The strongest childhood memories are often associated with smells, and memories triggered by fragrances often feel more vivid and emotional than those influenced by sights, sounds or tastes. Research has demonstrated that fragrance can stimulate learning and retention.

“Unlike other senses, smell needs no interpreter,” Ackerman writes. “The effect is immediate and undiluted by language, thought or translation. A smell can be overwhelmingly nostalgic because it triggers powerful images and emotions before we have time to edit them.”

Perfume, Ackerman says, is “liquid memory.” The classic 1922 perfume, Chanel No. 5, has a synthetic base but draws many notes and nuances from the plant world — including jasmine, rose, lily of the valley, orris, vetiver, sandalwood, cedar and vanilla.

Individual reactions to any scent vary widely, perhaps because of the power of scent memories, those associations and mental leaps our brains make when we catch a familiar smell. And usually we can’t say why a particular scent affects us. While our subtle, precise noses may be able to distinguish thousands of odors, we don’t have the ability or the language to describe all the scents we know.


The thousands of taste buds in your mouth can detect only sweet, sour, salty and bitter, leaving it to the nose to pick up every other nuance in food’s rainbow of flavor.

Bringing a garden fragrance indoors instead of buying it bottled creates a scent that is utterly personal (see story on Page 26 for recipes). Herb gardeners with a crafty side have a marvelous array of traditional fragrance crafts to try their hands at, from potpourris and wreaths to scented candles, herbal soaps and infused massage oils. But for those who don’t have the time or the inclination for a craft project, there’s a simple way to use herbs from your garden to fill up your house with penetrating fragrance: Simmer them.

Herbs and spices in a simmering potpourri release their aromatic oils quickly when set on the back of the stovetop at a slow simmer, generating enough fragrance to waft through the house and scent the air for a few hours. You can create veritable potpourris in your stewpot with what you have on hand and what you prune from the garden, without worry about fixatives or preservatives. It’s easy, inexpensive, creative, interesting and so very fragrant.

The practical side of simmering potpourris is also appealing. You can use up last year’s harvest of dried herbs, or the extra greenery when you cut back herb garden plants in the fall or spring, or whenever you have a handful left over from other projects. Simmering is a good way to use up that dry potpourri whose scent is starting to fade. After the plant material has turned to mush and released all its aroma in the simmering water, the contents of the pot can be dumped on the compost pile.

In dry climates or during the wintertime when houses are closed up and heaters turned on, an occasional simmering potpourri will add moisture to the air and make it more comfortable. Many herbs have antiseptic qualities and actually will freshen the air in a home; these include such fragrant favorites as lavender, rosemary, mints, eucalyptus and thyme.

The following recipe is an example of a fragrance blend for the stovetop that can create a scenario for romance. Other suggestions follow for herbal ingredients that have other effects. You can make a single simmering potpourri on the fly with what’s at hand. Or when you find a blend you like, you can prepare a batch of any size and store it in tins or jars until you’re ready to use it. The simple craft of simmering potpourris cries out for a playful hand and a touch of inventiveness.


1/4 cup rose petals, any color
2 teaspoons lavender flowers
Peel of 1/2 orange
1 teaspoon allspice berries

Use stainless steel or glass containers for potpourri ingredients, as plastic or aluminum can affect the scent. You can use as much of the plant material as you want, but the amounts shown here are suitable for a single simmering in about 1 quart of water. Put the pan of water on the stovetop (or in a warming dish) and heat until it reaches a simmer, with tiny bubbles rising to the surface but not hot enough to boil. As fragrance fills the air, keep your eye on it, replenishing the water as it evaporates so that it doesn’t run dry.


A most useful tool for the potpourri simmerer is a notebook. Learning the scents of the individual plants, and the components that contribute to the scent, is the first step to figuring out your response and getting in touch with what the fragrance can do for you. What does it remind you of ? A childhood memory, a person who was dear to you, a special holiday, or other pleasurable connotation? How does it make you feel? What words would you use to describe that scent? Write them down.

Then you can start trying different plants to see how their scents combine, and you can discern quickly how a hint of spiciness can add an invigorating tingle to the floral quality of other scents, what a bit of thyme or rosemary can add to the invigorating coolness of a mint, how the tang of citrus can balance the earthiness of other herbs. If two fragrances are similar, they will tend to blend together; if one is too overpowering, it can mask the other completely. Noting the ingredients you use and the proportions, and evaluating the scents you produce, is invaluable in terms of learning your fragrance preferences and being able to reproduce the scent whenever you want. Your notebook becomes a catalog of scents.

The ancient art of blending fragrances is very subjective, so you can’t go wrong. When you sniff the air to judge a scent, empty your mind and let it wash over you. Tap into your most primitive powers, and mingle the scent with the memories of your soul. Use it to transport yourself to faraway places and happier times.

Kathleen Halloran, former editor of The Herb Companion, is a freelance writer and editor in Las Vegas, where she enjoys a variety of scents and the art of making potpourri.