The 12 Most Recognizable Scents (of 1982)


In the early 1980s, psychologist William Cain asked a bunch of people to sniff lighter fluid—for science. Working with students at Yale University, Cain and his cohorts took 80 common scents and asked participants if they could identify them.   

The resulting paper, “Odor Identification by Males and Females,” was published in the Chemical Senses journal in 1982. Thirty-three years later, it’s both a snapshot of what our noses were once commonly exposed to and an example of how certain smells never go out of style. Go on and take a whiff.      

1. Coffee


Few of Cain’s subjects had any problem naming the sweet aroma of ground coffee, and it’s unlikely things would be any different in today’s Starbucks-dotted world. “Even people who don’t drink coffee often love the smell of it,” says Cain, who now a senior scientist at the Chemosensory Perception Lab in San Diego. “There’s a pleasantness to it that puts it categorically aside. There are other things on the list at least as familiar in terms of frequency, but this is somehow different. I think even kids like the smell.”

2. Peanut Butter


Yes, Cain had students sticking their noses in jars in a pre-peanut hysteria climate. No one died. But it is surprising a comparatively low-key smell was so easily pinpointed in the study, especially when different brands of peanut butter can have their own distinctive scent. One explanation might be that peanuts produce over 200 airborne molecules, a kind of olfactory symphony that’s easy to recognize.

3. Vicks VapoRub

Procter & Gamble

A mentholated cream, Vicks is actually designed to be pungent—a good way to stay memorable. It’s also able to assert itself into your sense memory with a brand name that can help word retrieval. “It has stability based on the name of the product,” Cain says. In his study, subjects who could use a specific name to recall products could repeat it 80 to 90 percent of the time. If they gave a more generalized term, their chances plummeted to 50 percent.

4. Chocolate


For this one, subjects were given a little leeway. “I can give you Hershey’s chocolate, and with good justification can say 'this is what chocolate is,'” Cain says. “But I can also give you other kinds of chocolates. It’s the kind of category in which you’re permitted a certain amount of variation, using the same name for variants of a product.”

5. Wintergreen Oil


A common scent (and flavor) in oral hygiene products, wintergreen is practically rammed down throats in the form of toothpaste, mouthwash, and candies like Life Savers—as well as cigarettes and chewing tobacco. Next to coffee, it might be the most common high-exposure item on the list.

6. Johnson’s Baby Powder

Austin Kirk, Flickr // CC BY 2.0

One outcome of the study that surprised Cain was the dominance of fabricated, manmade smells as opposed to organic scents. “Items that are not natural are incredibly stable in terms of perception,” he says. “One of them is baby powder that comes from Johnson’s. Even off brands are made to smell like it.”

7. Cigarette Butts


While people were certainly aware of the health risks of cigarettes in the early 1980s, it was still a relatively common habit indoors and out. “[The study today] would certainly change,” he says. “Smoking was ubiquitous then.”

8. Mothballs

As an insect deterrent, mothballs have fallen out of favor in recent years due to health risks associated with inhalation. Children are especially susceptible to DNA and red blood cell breakdowns when exposed to naphthalene, one of the active chemicals. (Don’t inhale mothballs, kids. And don’t eat ‘em, either.)

9. Dry Cat Food


That oddly processed, industrial odor of cat food is a good example, Cain says, of what he calls “decontextualizing” smells. “When you give someone a jar, they probably don’t expect it to be full of cat food,” he says. “It’s unpleasant.” Cain likens it to smelling ketchup on a hamburger, which is less odorous and potentially more enticing than smelling the condiment by itself.

10. Beer


Most all beer has a distinctive yeast smell, which researchers speculate may be due to its need to attract fruit flies so the fungi can hitchhike to other rotting pastures. In the case of Cain’s study, the reason for recognition may be far simpler: his subjects were college students.

11. Ivory Bar Soap

Mike Mozart, Flickr // CC BY 2.0

Like baby powder, Ivory’s distinctive smell provided subjects with stability. “These products are made with such high precision that they’re virtually identical every time,” Cain says. “The errors in odor identification come from fluctuations in stimulus.” One apple is not like another, or may be less ripe—but millions of bars of soap are engineered to mimic one another.

12. Juicy Fruit Gum

Will Culpepper, Flickr // CC BY-SA 2.0

Strangely, the women in Cain’s study were far more accurate in detecting Juicy Fruit than the men, though they weren’t any more likely to chew gum. But a large portion of Cain’s study was devoted to the fact that women are generally far superior to men in identifying smells, including supposed male-leaning scents like motor oil. They outperformed the men in 66 of 80 samples, though it may have more to do with being better at verbal recall than actual scent memory.

The one time men showed clear nasal dominance? Identifying Brut Aftershave. “Men were better at that,” Cain says. “Maybe it had something to do with [then-spokesman] Joe Namath.”

What scents do you think would dominate a list today? Let us know in the comments below.

Researchers Pore Over the Physics Behind the Layered Latte

The layered latte isn't the most widely known espresso drink on coffee-shop menus, but it is a scientific curiosity. Instead of a traditional latte, where steamed milk is poured into a shot (or several) of espresso, the layered latte is made by pouring the espresso into a glass of hot milk. The result is an Instagram-friendly drink that features a gradient of milky coffee colors from pure white on the bottom to dark brown on the top. The effect is odd enough that Princeton University researchers decided to explore the fluid dynamics that make it happen, as The New York Times reports.

In a new study in Nature Communications, Princeton engineering professor Howard Stone and his team explore just what creates the distinct horizontal layers pattern of layered latte. To find out, they injected warm, dyed water into a tank filled with warm salt water, mimicking the process of pouring low-density espresso into higher-density steamed milk.

Four different images of a latte forming layers over time
Xue et al., Nature Communications (2017)

According to the study, the layered look of the latte forms over the course of minutes, and can last for "tens of minutes, or even several hours" if the drink isn't stirred. When the espresso-like dyed water was injected into the salt brine, the downward jet of the dyed water floated up to the top of the tank, because the buoyant force of the low-density liquid encountering the higher-density brine forced it upward. The layers become more visible when the hot drink cools down.

The New York Times explains it succinctly:

When the liquids try to mix, layered patterns form as gradients in temperature cause a portion of the liquid to heat up, become lighter and rise, while another, denser portion sinks. This gives rise to convection cells that trap mixtures of similar densities within layers.

This structure can withstand gentle movement, such as a light stirring or sipping, and can stay stable for as long as a day or more. The layers don't disappear until the liquids cool down to room temperature.

But before you go trying to experiment with layering your own lattes, know that it can be trickier than the study—which refers to the process as "haphazardly pouring espresso into a glass of warm milk"—makes it sound. You may need to experiment several times with the speed and height of your pour and the ratio of espresso to milk before you get the look just right.

[h/t The New York Times]

Andrew Burton/Getty Images
job secrets
11 Behind-the-Counter Secrets of Baristas
Andrew Burton/Getty Images
Andrew Burton/Getty Images

Being a barista is no easy task, and it’s not just the early hours and the don’t-talk-to-me-unless-I’ve-had-my-coffee customers. While people often think working at a cafe is a part-time, temporary gig, it takes extensive training to learn your way around an espresso machine, and most baristas are in it for the love of coffee, not just to pay the bills. Mental Floss spoke to a few baristas working at the New York Coffee Festival to learn what exactly goes on behind the counter, and why you should never, ever dump your extra coffee in the trash.


One of the biggest misconceptions about the profession, says New York City-based barista Kayla Bird, is “that it's not a real job.” But especially in specialty cafes, many baristas are in it for the long haul. Coffee is their career.

“It's a chosen field,” as barista Virgil San Miguel puts it. “It's not like you work in a coffee shop because it's a glamorous job,” he explains. “It's more like a passion.”


“Being a really good barista takes a lot of studying,” explains Jake Griffin, a wholesale representative for Irving Farm Coffee Roasters who has worked in the coffee industry for almost a decade. “It can take a few years. You have to start to understand origins, production methods, where your coffee came from.” You have to go through an intensive education before you start pulling espresso shots for customers, so it's possible that the person taking your order and fetching your pastry isn't even allowed to make you a drink yet. “They have to be what we call 'bar certified' before they're even allowed on the machine,” he says. “Usually people start off in our cafes in various support roles, then start to go to classes and go through the training program.”


Sure, baristas take full advantage of all that free coffee. And if they work in their company’s training programs, their whole job is to drink coffee. But it has its downsides. “I taste—at minimum—ten shots of espresso a day,” John Hrabe, who trains baristas at Birch Coffee in New York City, says. On his busier days, it might be as many as 20. You get used to all the caffeine, he claims—at least until you take a few days off. “Then when you go on vacation and you're not working ... everyone's like, 'Why's John so tired?’”

Other baristas who have worked in the field for a long time say the same. “I’ve been doing this for 15 years, and I used to have five or six coffees a day,” Michael Sadler, who helped develop the barista education program at Toby’s Coffee, says. “Now I do two,” he says, both because of the caffeine-induced anxiety and the withdrawal headaches he would get on his days off.


Like any job, there are things that go on in coffee shops that the boss would definitely not approve of. According to one barista who has worked at both a corporate coffee chain and specialty cafes in Delaware and New York, coffee shops can get pretty rowdy behind-the-scenes. “If you see a barista with a lidded cup behind the bar, there's probably a 50/50 chance: It's either coffee or beer,” he says. “You never know.” And it’s not just the booze, either. “I’ve been a part of secret menus that have cannabis-infused coconut milk,” he explains. “I had a pretty good cappuccino.”


You don’t want to hold up the line telling a barista your life story at 7 a.m., but even if you’re in a hurry, don’t forget to say hi before you jump into demanding that large coffee. “Walking up to somebody and saying 'Almond latte,' when they just said 'How are you today?' is probably the biggest thing you can do to get on a barista's bad side,” Toby's Coffee's Sadler says. “It's like, exchange pleasantries, then get to business.”


Not everyone is super perky in the morning, but if you can’t be civil, you’re better off making your own coffee at home. At some places, if you get snippy with the employees, you’re going to get worse than furtive eye rolls between baristas (though you’ll get that, too).

“Be nice to your baristas, or you get decaf,” warns one barista. While it varies from cafe to cafe, multiple baristas told Mental Floss that it happens. Rude customers might get three letters written on their cup: “They call it DTB—‘decaf that bitch.’”

There’s a less potent way a barista can get back at you, too. If the hole in your coffee lid lines up with the seam of your paper cup, you’re going to get dripped on. And sometimes, it’s not an accident. “When a barista puts the mouth on the seam, they want it to leak on you,” a New York City-based barista explains.

Others are a little more forgiving of rude patrons. “I like making them the best drink that they've ever had, just to kill them with kindness,” one coffee shop employee says. “I don't want them to be like, ‘She’s a bad barista.’” Just to be safe, though, it's better to be nice.


“The longer you work in coffee, the more when someone walks in the door you read their personality type and say, I know exactly what you're going to drink,” Jared Hamilton, a self-described “espresso wizard” at the Brooklyn-based chain Cafe Grumpy, says. When I ask him to predict my drink, he proves his skills. “What you're going to drink is like, an alternative milk, flat white or cappuccino. So maybe soy, probably almond. Nonstandard. You don't want a lot of milk, just enough.” He’s not too far off—my go-to is, in fact, a non-standard, some-milk-but-not-too-much drink, a decaf cappuccino, though I drink regular milk in it. He points to another festival visitor who is dressed in business attire. "That guy right there, he drinks espresso all day," he guesses.

Depending on the coffee shop, the barista might know what customers want more than they do. Dominique Richards, who started her first barista job in Brooklyn three months ago, says she has to order for her customers around a third of the time. “Usually if someone's looking at the menu for more than 30 seconds, I jump in and say, ‘Hey, what would you like?’” She then asks them a few questions, like whether they want hot or cold coffee, and goes from there, often recommending lattes for people who are just getting into specialty coffee. “It's kind of a learning experience for the majority” of her customers, she says.


“People treat cafes like they're [their own] kitchen,” according to Cafe Grumpy’s Hamilton. “My favorite thing people do is when they walk in and they rearrange the condiment bar. Then they order, then they go use the condiments.” Apparently, some people are really particular about the location of their sugar packets. And if you throw off their routine, watch out. One of his colleagues describes a customer who threw a fit because the shop didn’t have a cinnamon shaker, demanding a refund for both her coffee and her pastry. (They eventually found some cinnamon for her.)


Even if you ask for room for milk in your drip coffee, the cup is still sometimes just a bit too full. It’s tempting to just pour a little into the trash can, but whoever has to take out that garbage is going to pay for it. “Please don't pour it in the garbage,” Bluestone Lane barista Marina Velazquez pleads. “Because at the end of the night, it ends up on our feet.” If the shop doesn’t have a dedicated container for you to pour out your excess coffee, take it back to the counter and ask them to dump a bit in the sink. Your baristas will thank you.


When you’re waiting in line, it may look like baristas are doing the same thing over and over for dozens of drinks. But in fact, every order presents its own challenges.

“There's probably not an appreciation for how much a coffee can vary,” explains Katie Duris, a former barista of 10 years who now works as a wholesale manager at Joe Coffee. High-quality coffee is “really dynamic as an ingredient,” she says. Baristas “have to make micro adjustments all day long. You have to change the grind based on the humidity in the room or a draft or how much coffee is in your hopper—if it's an espresso machine—so they're tweaking all day long … good baristas are making adjustments all the time.”


Making espresso drinks all day long can wear you out, and not just because you’re on your feet all day. There are also repetitive stress injuries to consider. “There's physical wear and tear on your joints when you're a barista,” Birch's Hrabe says. He’s worked in coffee for 11 years, and says that tamping espresso shots (compressing the grounds before brewing) day after day has given him tennis elbow. “It's totally common for baristas,” he says.

In short, baristas are probably doing more work behind the bar than you give them credit for, whether it’s dealing with customers or actually making coffee. “Being a barista is fun, but it's hard work,” Bluestone Lane's Velazquez says. “Everybody should be a barista at least once. I think it teaches humility.”


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