10 Chemistry Cooking Tricks From an Award-Winning Teacher (and Foodie)


Before diving into the kitchen this Thanksgiving, it’s helpful to have some basic chemistry knowledge up your sleeve. Ever wondered what the fastest way to defrost a turkey is? Or how to make the perfect, lump-free gravy every time? Yesterday, the American Chemical Society's Sally Mitchell—an award-winning high school chemistry teacher and Albert Einstein fellow at the Department of Energy’s Office of Science in Washington D.C.—hosted a Reddit AMA to share some kitchen chemistry tips ahead of Thanksgiving. Outside of her own classroom, Mitchell teaches other chemistry teachers how to incorporate food chemistry into their lessons. Here are her 10 best chemistry-smart cooking hacks to help you concoct a fantastic feast this holiday.


When is comes to stuffing, texture is key. According to Mitchell the secret to stuffing that’s neither overly dry or overly soggy is to make sure you’re starting out with stale bread: “The secret to a good stuffing is to make sure the bread is dried before adding the butter and water. If you used a cubed baguette, you need to dry out the bread over night by leaving it out exposed to the air or dry it slowly by placing the cubes in a warm oven until they are dried out before mixing in the other ingredients.”


All it takes is one dash of salt too many to push a dish into inedible territory. When seasoning your dishes this Thanksgiving, Mitchell says to be mindful of the temperatures of the food you’re preparing: “If you were to take a food that is hot such as soup and salt it to taste and then cool it down, it would taste too salty. So cold enhances salty and hot reduces the sensation of saltiness. Keep that in mind when you salt food for others.”

For home cooks who have already salted their food past the point of no return, Mitchell says there’s not much that can be done. This is especially true when it comes to baked goods, but she still attempts to find the silver lining in your over-salted cookie dough: "Too much salt in your cookies is hard to overcome, taste-wiseyou should try to shape them into objects with cookie cutters and use them for your decorations since the additional salt will help deter bacterial growth."


It’s best to plan ahead as far as possible when it comes to Thanksgiving dinner. But if you find yourself on Wednesday night with a fully-frozen turkey on your hands, Mitchell has some advice on how to get it thawing as quickly as possible: “Give it a bath. I would read the label on the wrapping and follow it. If you need to speed this up, a cold-water bath with running water in it defrosts the fastest. Moving water will defrost faster than standing water."

And if you still haven’t gotten around to picking up your turkey for Thanksgiving, Mitchell’s primary piece of advice is to buy it fresh and avoid the defrosting process all together.


When experimenting with cookie recipes, Mitchell says that there is a noticeable difference in cookies that use shortening versus cookies that use butter as their source of fat: “You can make them thin and crisp, soft and puffy, or somewhere in between … Butter will tend to make cookies spread out and shortening makes them puff more.”


Not all creams are created equal. It may be tempting to substitute heavy cream with light cream and half-and-half when that’s all you have on hand, but there are chemical differences in these ingredients that can have an impact on your final product. According to Mitchell, “The difference between all the different types of creams is the percentage of butterfat. Half and half contains 10 to 18 percent butterfat, light coffee cream contains 18 to 30 percent butterfat, light whipping cream contains 30 to 36 percent butterfat, and heavy cream contains at least 36 percent butterfat. To whip cream, it must contain at least 30 percent butterfat. The more the butterfat, the faster the cream will whip and the firmer it will be. (If you over whip your cream, it turns into butter and butter milk).” But if you’re just looking for a cream to use in your green bean casserole this year, Mitchell says whatever you have in your fridge will do.


Nothing ruins a plate of food faster than drowning it in unsavory, lumpy gravy. After years of putting up with awful gravy from her mother, Mitchell was inspired to teach herself how to make it the right way: “My inspiration to becoming a good cook was my mother, because she made the ‘worst’ gravy each year. I learned how to work with flour and thickening agents because of her gravy mistakes, and now I make perfect gravy every time. I recommend the roux…but you can always use the correct flour (gravy flour, you can buy this at the grocery store under several brand names) and always shake the flour in COLD water before adding to the hot drippings.”


Different recipes call for different baking temperatures. For those of you who've ever wondered how the level of heat in your oven impacts the final taste of your dish, Mitchell breaks down the delicious chemistry: “Let me focus on caramelization of sucrose (common table sugar). At 170 degrees Celsius (340 degrees Fahrenheit) the sucrose molecule will start to break apart. As the process proceeds, hundreds of new and different compounds form giving sour and bitter flavors, and browning occurs. The sweetness goes down while the darker and more bitter the food gets. This is why sometimes I bake my cookies at a lower temperature to prevent caramelization and sometimes I bake them at a higher temperature. It depends on the final flavor I am trying to create.”


Deciding when to toss out your Thanksgiving leftovers can quickly become a game of chance. Just because your turkey has been cooked all the way through doesn’t mean it can’t still harbor harmful bacteria after sitting in your fridge for too long. "Remember to always heat up food to at least 55 to 60 degrees Celsius (140 degrees Fahrenheit) to make sure bacteria that can cause foodborne illness is eliminated,” says Mitchell. “They (food recommend eating leftovers within 4 days if stored properly.”


Anyone who’s tried substituting baking powder for baking soda in a recipe knows there is indeed a difference between the two. Mitchell explains the chemical significance of both components in your baked goods: “Baking soda is used when ingredients are acidic. When a carbonate (baking soda is sodium hydrogen carbonate) mixes with an acid (vinegar, lemon juice, chocolate, brown sugar are just some examples of acidic foods) a chemical reaction takes place and carbon dioxide is released. This along with steam generated in the baking process will help leaven your brownies. But for an added lift, baking powder is also added. Baking powder usually contains an acid salt that neutralizes the baking soda found in the baking powder mixture and more carbon dioxide bubbles are released.”


The egg is a magical ingredient. They lend themselves to many different applications and cooking methods, and as Mitchell explains, “raw” eggs can even be made safe to eat through a nifty chemistry trick: “When you cook an egg, at specific temperatures for a specific amount of time, wonderful things can happen. Eggs can be pasteurized in their shells without really cooking them. Now you can have raw eggs, safe to use in recipes for mayo or Caesar salad dressing, without the worry of foodborne illness.” She also illustrates how slow-cooking an egg sous vide–style can result in the perfect boiled egg: “Eggs contain different kinds of proteins and each has its own setting point temperature. By controlling the temperature, you can set the proteins gently and cook them all the way through without the harsh temperatures you cannot control from directly cooking on the stove top.”

When You Feel "Chemistry" With Someone, What's Actually Going On?

We know chemistry when we feel it with another person, but we don't always know why we're drawn to one person over another. Is it just a cascade of neurotransmitters and hormones conspiring to rush you toward reproduction? Is it attraction borne of a set of shared values? Or is it bonding over specific experiences that create intimacy?

It's probably a combination of all three, plus ineffable qualities that even matchmaking services can't perfectly nail down.

"Scientists now assume, with very few exceptions, that any behavior has features of both genetics and history. It's nature and nurture," Nicole Prause, a sexual psychophysiologist and neuroscientist, tells Mental Floss. She is the founder of Liberos, a Los Angeles-based independent research center that works in collaboration with the University of Georgia and the University of Pittsburgh to study human sexual behavior and develop sexuality-related biotechnology.

Scientists who study attraction take into consideration everything from genetics, psychology, and family history to traumas, which have been shown to impact a person's ability to bond or feel desire.


Helen Fisher, a biological anthropologist at Rutgers University,'s science advisor, and the author of Anatomy of Love: A Natural History of Mating, Marriage, and Why We Stray, breaks down "love" into three distinct stages: lust, attraction, and attachment. In each stage, your body chemistry behaves differently. It turns out that "chemistry" is, at least in part, actual chemistry. Biochemistry, specifically.

In the lust and attraction phases, your body is directing the show, as people can feel desire without knowing anything personal about the object of that desire. Lust, Fisher asserts in a seminal 1997 paper [PDF], is nothing more than the existence of a sex drive, or "the craving for sexual gratification," she writes. It's a sensation driven by estrogens and androgens, the female and male sex hormones, based in the biological drive to reproduce.

Attraction may be influenced less than lust by physiological factors—the appeal of someone's features, or the way they make you laugh—but your body is still calling the shots at this stage, pumping you full of the hormones cortisol, adrenaline, and dopamine, effecting your brain in a way that's not unlike the way illicit substances do.

Fisher has collaborated multiple times on the science of attraction with social psychologist Arthur Aron, a research professor at Stony Brook University in New York. Aron and his wife Elaine, who is also a psychologist, are known for studying what makes relationships begin—and last.

In a 2016 study in Frontiers in Psychology, the researchers proposed that "romantic love is a natural (and often positive) addiction that evolved from mammalian antecedents by 4 million years ago as a survival mechanism to encourage hominin pair-bonding and reproduction, seen cross-culturally today."

In the attraction phase, your body produces increased amounts of dopamine, the feel-good chemical that is also responsible for pain relief. Using fMRI brain imaging, Aron's studies have shown that "if you're thinking about a person you're intensely in love with, your brain activates the dopamine reward system, which is the same system that responds to cocaine," he tells Mental Floss.

Earlier, Fisher's 1997 paper found that new couples often show "increased energy, less need for sleep or food, focused attention and exquisite delight in smallest details of this novel relationship."

The attachment phase is characterized by increases in oxytocin and vasopressin; these hormones are thought to promote bonding and positive social behaviors to sustain connections over time in order to fulfill parental duties.

There is no hard and fast timeline for how long each phase lasts, as it can vary widely due to gender, age, and other environmental factors, Fisher writes.

Additionally, while oxytocin has long gotten the credit for being the love hormone, Prause says that scientists are now "kind of over oxytocin," because it has broader functions than simply bonding. It also plays a role in the contraction of the uterus to stimulate birth, instigating lactation, and sexual arousal; low levels have been linked to autism spectrum disorders. 

Now they're focusing on a charmingly named hormone known as kisspeptin (no, really). Produced in the hypothalamus, kisspeptin plays a role in the onset of puberty, and may increase libido, regulate the gonadal steroids that fuel the sex drive, and help the body maintain pregnancy. But Prause says there is a lot more study about the role kisspeptin plays in attraction.


Biology may explain our initial attraction and the "honeymoon" phase of a relationship, but it doesn't necessarily explain why a person's love of obscure movies or joy of hiking tickles your fancy, or what makes you want to settle down.

The Arons' numerous studies on this subject have found connection boils down to something quite simple: "What makes people attracted to the point of falling in love—presuming the person is reasonably appropriate for them—is that they feel the other person likes them," he says. 

In the process of doing research for her book How To Fall in Love With Anyone, writer Mandy Len Catron of Vancouver became her own test subject when she came across the research the Arons are most well-known for: their 36 questions, which promote bonding.

The questions were originally designed to "generate intimacy, a sense of feeling similar, and the sense that the other person likes you," Aron explains. Romantic love wasn't the goal. "It was a way of creating closeness between strangers."

The Arons first tested their questions by pairing up students during a regular class section of a large psychology course, as they related in a paper in the journal Personality and Social Psychology Bulletin. Some students were paired with someone of the same sex, while others were matched with someone of the opposite sex. Each partner then answered a series of 36 increasingly personal questions, which took about 45 minutes each. (Question 2: "Would you like to be famous? In what way?" Question 35: "Of all the people in your family, whose death would you find most disturbing? Why?") Small talk during class hadn't made them bond, but the questions made the students feel closer.

In another version of the study, heterosexual, opposite-sex pairs follow the 36-question session with four minutes of staring deeply into each other's eyes.

Catron decided to test these methods out with a casual acquaintance, Mark, over beers at a local bar one night. They were both dating other people at the time, and no one exclusively. As she answered the questions and listened to Mark's answers, "I felt totally absorbed by the conversation in a way that was unlike any of the other first dates I was having at the time with people I met online," Catron tells Mental Floss.

She was ready to skip the four minutes of soulful eye gazing, but Mark thought they should try it. "It was deeply uncomfortable, but it was also an important part of the experience," she recalls. "It's so intimate, it requires you to let your guard down."

The process instilled in Catron a deep feeling of trust in Mark and a desire to know him better. Within three months, they began dating in earnest. Now, more than three years later, they live together in a condo they bought.

The Arons' questions offer "accelerated intimacy," she says, in a time of increasingly online-driven dating experiences.


Despite all that we’ve learned, scientists may only ever be able to brush up against the edge of a true understanding of "chemistry." “We understand a fair amount about what happens when [attraction has] already occurred, but we're really bad at predicting when it will happen," Prause says. "People who try to claim magical matchmaking, or that they're going to somehow chemically manipulate an aphrodisiac or something—well good luck! Because we can't figure it out.”

And anyway, what's romance without a little mystery?

If you must have a definitive answer to the puzzle of interpersonal chemistry, Prause says to keep this in mind: "The best predictor of long-term outcomes is shared values."

David Monniaux, Wikimedia Commons // CC BY-SA 3.0
The Thermodynamic Genius of the Classic Drinking Bird Toy
David Monniaux, Wikimedia Commons // CC BY-SA 3.0
David Monniaux, Wikimedia Commons // CC BY-SA 3.0

If you're familiar with the drinking bird toy, you know it as a cheesy knickknack that's adorned office desktops for decades. But anyone with a background in thermodynamics knows that the novelty item deserves more credit. In his video spotted by Sploid, Bill Hammack—a.k.a. engineerguy—explains the impressive science at work every time the toy takes a sip.

To pull off its famous trick, a drinking bird toy must contain a special chemical compound called methylene chloride. When stored inside the toy it looks like colored water, but its properties are unique: It can transition easily from a liquid to a gas by essentially boiling at room temperature. Evaporated methylene chloride fills the bird's head while liquid methylene chloride fills the base of its body. Pressure differences caused by the condensing gas in the head encourage the liquid in the base to rise to the top of the toy, shifting the weight so its upper half topples forward into the glass in front of it. The liquid methylene chloride drains out in this new position and the balance of gas and liquid is restored. As long as the bird has enough room-temperature water to drink, the water will cool the methylene chloride vapor and start the whole process over again.

The result is a seemingly simple toy whose principles were actually complicated enough to baffle Albert Einstein. You can watch Hammack give a more detailed explanation of the science at work in the video below.

[h/t Sploid]


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