What's the difference between cologne, eau de parfum and perfume?

In 1709, chemist Johann Farina created a fragrance blend of citrus and cedar and named it for the town where it was conceived. Cologne, Germany, thus became the production point of one of the most popular scents of its time.

Farina's Eau de Cologne is still sold today in its original recipe, and that product is the only true Cologne (with a capital C), much the way the only true Champagne comes from the Champagne wine region in France. Today, though, many people -- especially in the United States -- use the term "cologne" (lowercase) to mean "men's fragrance," a cultural tweak that has become common usage.

What all colognes, true or not, have in common is their concentration of essential oils. Eau de cologne is a weak formulation, typically containing anywhere from 2 to 5 percent essential oils in a base of mostly alcohol but also water, which characterizes most fragrances. The low concentration results in several qualities that distinguish cologne from other forms of scent. First, the cost per ounce is one of the lowest, and the scent only lasts for an hour or two. Second, it's the scent's top notes (the first ones you smell after application) that are dominant. Because cologne fades quickly, other scent components of the recipe tend to fall away, resulting in a product that may smell markedly different from other versions of the same fragrance. (See What does dry-down mean? to learn about fragrance notes.)

The formulation known as eau de toilette is close to cologne on the concentration scale, containing approximately 5 to 10 percent fragrance oils. Some perfume houses use the terms interchangeably, along with "eau fraîche" (or "fresh water"), to describe a low-concentration product. Regardless of the name, it's a formulation that allows the user to apply more, and more often, without being over-scented.

Eau de parfum, on the other hand, requires more restraint.

If fragrance progression follows social norms (and many would say it does), then the increased popularity of eau de parfum in the 1980s might reflect the stereotypical wearer of that decade: bold, financially savvy and tending toward excess.

More concentrated than eau de cologne and eau de toilette, eau de parfum ranges from about 10 to 15 percent essential oils. The result is a fragrance that lasts a lot longer than cologne, up to five hours, so it requires less-frequent application (and women on the go rejoice). It's not so strong, however, that it needs to be applied as drops; eau de parfum is still light enough to be sold as a purse-worthy, high-volume spray (again, women on the go rejoice).

This type of fragrance puts the attention on the middle notes, which take over after the top notes fade. Middle notes, sometimes also known as "heart notes," are dominant from about 15 minutes to a couple of hours after application and are considered to be the core of the scent. Eau de parfum is more expensive than eau de cologne and eau de toilette, so it's a less popular variety. Since it lasts so much longer, though, and can be applied in smaller doses, many people find it to be an affordable formulation.

And then there's perfume, which few would ever call affordable. It's the original, the elite, the pure.

The highest-concentration scent format, perfume (also called parfum, parfum extrait or perfume extract) has traditionally scented the wealthy. It's the purest of the fragrance recipes, with the highest concentration of expensive essential oils and the least amount of alcohol and water. In some cases, it may contain no water at all.

Historically, perfume is the original scent, the base from which all other varieties are diluted. Perfume concentrations range from 15 percent all the way up to 40 percent, with an industry average of about 25 percent. Unlike eau de parfum and eau de cologne, which may be applied liberally and practically anywhere, perfume is meant to be applied in tiny amounts using a dropper, and scenting only the pulse points, including the insides of wrists and elbows, the throat, behind the ears and between the breasts. At these points, the skin is warmest, allowing for the greatest fragrance release.

Of all scent varieties, perfume lasts the longest, up to seven hours. Its concentration also provides for the greatest depth of scent, with top, middle and base notes all having ample time to develop. It also offers some price justification: Perfume simply has more of the good stuff.

Thus the "Coco" parfum selling at 10 times the price of the eau de toilette. Brand name plays into the price, too, of course. It's tough to imagine concentration accounts entirely for Clive Christian's "No. 1," which runs $865 for 1.6 ounces. Though it's worth noting that if you're partial to that scent (Neiman Marcus calls it "Oriental-ambery"), it really is all or nothing: No. 1 doesn't come in eau de parfum.

For more information on perfume, fragrance chemistry and related topics, check out the links on the next page.