Coffee is one of the most well loved beverages in the world. Statistics show that more than half the population in the U.S. drink coffee on a daily basis. Further, those individuals drink 3.1 cups of joe every single day.1
In the last several years, coffee has been identified — as has that other well loved drink, tea — as a healthy beverage if consumed in optimal amounts. Coffee drinking is associated with reduced risk of an early death and heart-related illnesses, cancer, diabetes, cirrhosis and nonalcoholic fatty liver disease. Tea has been linked to reduced risks of stroke, diabetes and depression, as well as improved blood pressure, lower rates of obesity and moderated glucose levels.
Adding cream to coffee — and for some, to tea — changes everything, and for more than just taste. It has to do with the temperatures, but it’s become a fantastic debate over decades and even centuries. Scientists were reportedly fascinated with a slow-motion video (recorded at 2,000 frames per second) of a drop of milk being dropped into a cup of hot coffee, because for a few nanoseconds, the cream floated.
The featured video notes that when you mix two blendable liquids, they usually combine immediately. But when there’s that brief delay before it sinks, the base of the milk heats a tiny amount, but enough for the surface area of coffee directly under it to cool.
“Molecules in both the milk and coffee start moving in a circular direction, which guides the airflow around the bottom of the drop, making enough pressure to ‘levitate’ the drop. Researchers say you could theoretically levitate a drop of milk forever, as long as the coffee stays hot, and the milk stays cold.”2
John Bush, a professor of Applied Mathematics at MIT, says if it were possible to maintain the temperature difference, the cream could be “levitated” indefinitely, and that while it might be simpler to place a hot drop on a cold bath, it would work if you could add some sort of heating element to the inside of the drop.
The vital part of the discussion, the video clarifies, is that the discovery goes far beyond coffee or tea and milk, because keeping liquids separate is crucial in other arenas, such as inkjet printing and DNA testing. In fact, scientists say it could influence the way technology is advanced, and improve scientists’ understanding of how droplets behave in nature.
Is it semantics whether the milk or tea goes first?
Writer and editor Steve Rousseau at Digg agrees that people should place their cream in their coffee before their milk, but for simpler reasons. “If you pour the cream in first and then add the coffee, everything stirs itself.”3 Adding the cream first might make it hard to place in the right amount, he adds, but only at first. With practice, you should be able to nail it.
In England, where the beverage preference is tea over coffee, The Guardian, a newspaper founded in 1821,4 published a piece in 2014 stating there was scientific proof that to make the perfect British cup of tea — “The most vital discovery in the history of mankind. Fire is a close second, as you need it to boil water.”5 — the milk should go into the cup first.
Who knew it would be such a point of contention? The article noted a Dr. Stapley of Loughborough University who tested the theory and concluded that putting the milk into the cup after the boiling water was “incorrect.” It caused the milk to heat unevenly, as the proteins in the milk would “clump,” which changed both the texture and taste. But besides the water and the milk, there’s also the teabag to consider, and the order it’s added to the cup, as well.
It also refuted any suggestion that coffee might be more well loved in Fantastic Britain than tea, especially with the checkered history of the tea leaf, which was the subject of what one author called “greatest single act of corporate espionage in history.”6
Then there’s the debate about the temperature of the water used to make the perfect cup of tea, which supposedly needs to be kept at the boiling point even as it’s being poured. Another argument is that water shouldn’t be boiled more than once because it might make the tea taste “flat.”7 One claim of Yorkshire Tea maintains that certain protocols must take place in order to “turn a humble tea bag into a cracking cup of tea.”8
It’s not about coffee or cream; it’s the chemistry
An fascinating experiment took place in the early 1920s. Mathematician Ronald Fisher, knowing an algae biologist named Muriel Bristol liked milk in her tea, took her a cup, but made the mistake of pouring the milk in first. Bristol was indignant, insisting that milk should be added to the tea, not the other way around.
Provoked by her pettiness, Fisher’s argument was that thermodynamically, what possible difference would it make which went into the cup first? Bristol countered that it made a difference to her, and that she could taste the difference. It must have been an fascinating discussion to onlookers who ambled over to see if the altercation might devolve into fisticuffs.
Then William Roach — Bristol’s fiancé, it turned out — suggested an impromptu experiment. Eight cups of tea were randomly lined up before Bristol. Only Fisher and Roach knew which four cups had milk poured into them before the tea and which had tea in them first. Imagine Fisher’s chagrin and bewilderment when Bristol declared each cup correctly. Science History Institute clarifies:
“It turns out adding tea to milk is not the same as adding milk to tea, for chemical reasons. No one knew it at the time, but the fats and proteins in milk — which are hydrophobic, or water hating — can curl up and form small globules when milk mixes with water. In particular, when you pour milk into boiling hot tea, the first drops of milk that splash down get divided and isolated.
Surrounded by hot liquid, these isolated globules get scalded, and the whey proteins inside them — which unravel at around 160ºF — change shape and buy a burnt-caramel flavor. … In contrast, pouring tea into milk prevents the isolation of globules, which minimizes scalding and the production of off-flavors.”9
In the early part of the 1920s, scientific standards and controls were rare and the methods used were crude. The fascinating turn of events at the tea party became downright pivotal for Fisher because he couldn’t help mulling over the implications of statistical analysis. As his job was essentially to figure out more accurate testing methods for clinical trials (then simply called experiments), the door of opportunity was open and he walked through it.
Fisher used Bristol’s tea trials and broadened its adaptations for scientific assertions conducted over subsequent months. He wrote about this work in his book, “The Design of Experiments,” as well as his first work, “Statistical Methods for Research Workers.”10 He laid out concepts for statistical analysis, many of which are still used today, mostly because the tempest in a teapot, as it were, became the basis of predictability and counting sequences. Fisher himself noted:
“Our experiment consists in mixing eight cups of tea, four in one way and four in the other, and presenting them to the subject in a random order.
The subject has been told in advance of what the test will consist, namely that these shall be four of each kind, and that they shall be presented to her in a random order, that is an order not determined arbitrarily by human choice, but by the actual manipulation of the physical apparatus used in games of chance.”11
Health advantages from coffee, but creamers, not so much
It’s beside the point that drinking coffee is associated with a number of health advantages, such as better brain function, enhanced long-term memory, healthier hearts and a whole gamut of other benefits, according to a 2017 study.12
But a substance known as acrylamide, a known carcinogen and potential neurotoxin, has been identified as a potential problem when coffee is brewed, or more precisely, depending on the way it’s brewed. It’s a chemical made when carbohydrate-rich foods are cooked at high temperatures, but it’s also found in both drinking water and waste water, as well as charred foods. A judge in California ruled that coffee should come with a cancer warning for that reason.13
Further, some contend that the caffeine (one reason coffee, tea and chocolate are so well loved) can disturb your sleep, which becomes a health hazard of its own. Dark chocolate, more so than milk chocolate, has been found to be healthy in moderation. But adding fake creamers to coffee and tea, or what too often passes for cream, can be more of a problem.
Ingredients like partially hydrogenated oils, high fructose corn syrup, monosodium glutamate, dipotassium phosphate and an array of other chemically derived substances make your “creamer” more of a synthetic, chemically-based hazard that happens to taste excellent.
Research suggests there’s a better way to mix cream into your coffee. The upshot is there’s a scientific reason why gourmet chefs, before adding cream to a recipe, sometimes mix small amounts of the dish with it separately first and stirring it together before pouring it into the finished product.