What Causes “Old Person Smell”?

iStock / Koldunov
iStock / Koldunov

Reader Sarah writes in to ask, “What is it that causes that distinctive 'old person' smell? Whatever it is, it seems to be common to all elderly people. Is it inevitable or is there something you can do to avoid it?”

Ever notice that your grandparents and their house had a dull, kind of sweet stink to them? You’re not alone. Old people really do have a chemically-distinct odor.

Like other body odors, this “old person smell” is produced when chemicals from the skin glands get broken down into small odorous molecules that waft away into the air. The specific chemical that gives old folks their unique odor, scientists suspect, is a compound called 2-nonenal. Created by the oxidative breakdown of other chemicals over time, it produces what’s described as an “unpleasant greasy and grassy odor” in people and is also responsible for some of the “cardboard” flavor of stale beer.

In 2000, Japanese researchers found that people’s concentration of 2-nonenal increased with age. They had 22 people, ranging in age from 26 to 75, wear odor-collecting shirts to bed for a few nights and then analyzed the molecules that adhered to the cloth. They found more 2-nonenal in the shirts worn by people over 40 years old than they did in the younger subjects. And in the over-40 crowd, the concentration of 2-nonenal increased significantly with age, with the oldest subject producing almost three times as much as the middle-aged subjects. 

The researchers didn’t see any other odor compound increase with age like that, and think that the “deterioration of body odors” in the elderly, as they politely put it, can be pinned on 2-nonenal. But why does the compound increase as a person ages? The researchers also noted the presence of more omega-7 unsaturated fatty acids in the shirts worn by the older subjects, and think that the 2-nonenal comes from the breakdown of these fatty acid chains. The reason the fatty acids increase with age, meanwhile, is still unclear. The researchers speculate that it might be because of age-related changes to metabolism or changes in the amount of some other chemical in skin secretions.

Another big question still hanging in the air is what purpose, if any, an age-related change in smell serves. Humans and some non-human animals can tell the difference between older and younger individuals by smell, and some animals are known to be more attracted to the odor of older individuals and have more success mating as they age. One possible explanation for this is that older individuals may have some genetic advantage that allowed them to survive longer and makes them more attractive mates, and that distinct age-related odor is an advertisement for their genetic quality. It’s not clear that this is what actually happens, but if it is, it’s hard to imagine smell having much of an effect with humans when we place such high value on the physical attractiveness and other qualities of youth.

The fact that old person smell is usually thought of as unpleasant doesn’t seem to be a stumbling block here, though. Research subjects who didn’t know the source of the smell rated old person odors as less intense and less unpleasant than odors from younger people—suggesting that the smell on its own isn’t bad, but is perceived that way in certain contexts.

What Is Figgy Pudding Anyway?

bhofack2/iStock via Getty Images
bhofack2/iStock via Getty Images

"We Wish You a Merry Christmas" is an ode to figgy pudding disguised as a straightforward Christmas song. Three out of four verses in some versions are dedicated to the dish. So after listening to enough holiday music this December, you may start to wonder: What is figgy pudding anyway? And is it really so good that you'd actually beg for it on a stranger's doorstep through song?

According to NPR, figgy pudding, also called plum pudding, isn't pudding—at least not the kind of pudding many Americans think of when they hear the word—and it contains neither figs nor plums. In the UK, pudding is used as catch-all to describe any sweet dish served after a meal. Figgy pudding isn't creamy or custardy, but it is a sugary cake, which qualifies it as pudding overseas.

In its most basic form, figgy pudding is a steamed, often domed-shaped cake made with alcohol and dried fruit. The first version of figgy pudding surfaced in 14th-century Britain. Back then, it was a stew-like, savory dish containing beef and mutton as well as fruit and wine. In the 15th century, this mixture was stuffed into animal casings to make sausages that would last through the winter.

By the end of the 16th century, figgy pudding had transitioned to a fully sweet dish—right around the same time when carolers started singing "Now bring us some figgy pudding" to their wealthy neighbors around Christmas. Today, the dessert is commonly filled with currants, raisins, and soaked in rum or brandy.

So where did the first half of its name come from? In pre-Victorian England, the word plum was applied to any type of dried fruit, including raisins, so plum pudding caught on. Figs occasionally appeared in recipes throughout the dish's history, though they're not considered a traditional ingredient.

If you're thinking about cooking a throwback feast this Christmas, don't stop at figgy pudding. From oyster stew to mincemeat pie, here are some more classic British dishes that have ties to the holiday.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

What Exactly is Christmas Tree Flocking?

iStock.com/Spiderstock
iStock.com/Spiderstock

Of the many curious holiday traditions (figgy pudding? wassailing?), one of the oddest has to be spraying down small trees with a mixture of adhesive and cellulose fibers to satisfy our longing for a white Christmas.

That’s what’s happening when you adorn a tree with artificial snow, otherwise known as flocking. And yet, when decorated and lit up, there’s something beautiful and warmly nostalgic about a well-flocked Christmas tree. Here’s how professionals manufacture this Christmas miracle.  

The History of Flocking

We’ve been trying to get that snowy look on Christmas trees for longer than you might think, dating back to the 1800s using substances like flour or cotton. A 1929 issue of Popular Mechanics recommended varnish, corn starch, and flakes of the silicate mineral mica. 

But tree flocking as we know it really caught on in the late 1950s and 1960s, along with aluminum trees and other glitzy (if not natural-looking) decor of the post-war boom. General Mills marketed Sno-Flok home kits, to be applied using a gun that attached to a vacuum cleaner.

Such home kits are not so popular these days, says Tom Leonard, owner of Peak Seasons, one of the country's largest manufacturers of Christmas tree lots supplies and tree flock. Flocking itself, however, has retained a level of appeal. “Sunbelt states use a lot of it because there’s no snow there,” Leonard tells Mental Floss. “It’s tremendously popular. The West Coast, the South, and the Southeast, the vast majority of it is sold in those zones.”

The Science of Flocking

So what exactly is flocking? At its core, flocking means attaching tiny fibers to a surface to create texture (the process is also used in fashion, home decor, and crafts). The Peak Seasons recipe includes paper pulp as fiber, corn starch as adhesive, and boron as a flame retardant—there’s a safety benefit to flocking.

And the company makes a lot of it. Leonard says they're the largest manufacturer of flock in the United States and Europe. “I don’t want to share [how much], but we sell lots of flock. I mean truckloads and truckloads.”

Based in sunny Riverside, California, Peak Seasons starts with paper and a grinder. “It’s like a big roll of toilet paper and it weighs a ton and you feed it into a machine and it comes out a powder,” Leonard says. The exception is certain bright colors—flock comes in white, black, pink, ice blue, royal blue, red, green, gold, and purple—which require cotton fibers instead of paper to hold the dye. The final product is almost like baby powder, shipped all over the country in large, cement-bag-sized bags.

From there you need to affix the stuff in a nice even coat, which is where flock machines like the Mighty Sno-Blower come in. They’re basically big tanks that hold varying amounts of flock depending on the model, plus a mechanism at the bottom to fluff up the powder. The machine then pumps the powder through a hose, and a gun at the end mixes it with a mist of water.

And that’s how flock is born.

The Art of Flocking

You don’t have to go with a professional flocker, or even use manufactured flock. There are all sorts of DIY recipes that include things like soap flakes or even desiccated coconut flakes. But if you do go pro, you want to be in the hands of someone like Paul Iantosca, who has been flocking trees in the Boston area for 20 years.

Flocking one tree in bright purple (white is still most popular), Iantosca first sprays it down with water. Then, in an area closed off with plastic sheeting, he fires up the blower and blasts the tree evenly with what looks like a purple fog. The stuff gets everywhere. He wears a mask to keep it out of his nose, but some high-volume flockers wear full protective coveralls. 

The tricky part to flocking is that you can’t tell if you got it right until it dries. When it goes on, it’s cold and wet like paste. But as it dries, the Christmas magic kicks in and it puffs up, turning into fluffy white (or, in this case, purple) fuzz firmly affixed to the needles.

There are, of course, pitfalls. Not enough water, and the flocking falls off and makes a huge mess. A flocked tree can’t get wet a second time. “It won’t dry again. It’s disgusting actually,” Iantosca says. Also, when you flock a tree, the color highlights its flaws. A janky tree turns into a weird, uneven shrub.

But if you get it right and string it up with lights, you’ve got a real stunner on your hands. Iantosca’s had flocked trees for his own home for the past 10 years and his kids won’t let him go back.

“When you plug that thing in, it absolutely glows inside," he says. "It’s unbelievable.”

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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