It takes 32 minutes to boil a perfect egg, according to science. We agree.
Italian scientists claim to have found the scientifically best way to make a hard-boiled egg. After trying it for ourselves, we can confirm that the egg was delicious.
It seems like a simple culinary task, but cooking a hard-boiled egg has caused many a furrowed brow in the kitchen and spawned a cottage industry of techniques and tips. Who among us hasn't been disappointed to crack open an egg we assumed we had cooked to perfection, only to find the insides either rock hard or distressingly liquidy?
According to a team of Italian researchers, there is a good reason why boiling the perfect egg is such a challenge: albumen (the egg white) and yolk require two different temperatures for optimal cooking. That’s around 185°F for the former and approximately 149°F for the latter.
Writing in the journal Communications Engineering, researchers from the University of Naples Federico II claim to have discovered the method that best cooks both albumen and yolk and leads to eggs that are both more flavorful and nutritious than those cooked by other methods. The drawback? You’ll need two pots of water, a thermometer, and just over half an hour.
The technique involves a pot of boiling water and a pot or bowl of water that is kept at approximately 86°F. The key is to place the eggs into the boiling water for two minutes, then into the cooler water for two more minutes and back into the boiling water again, the process repeating for eight full cycles, or 32 minutes.
And while I was curious about how this research team developed such a complicated recipe, I immediately had one question: is it worth it?
What we found
Eager to put their findings to the test, I ran my own experiment, with one pot of constantly boiling water and one that I tried to maintain at roughly 30°C (86°F) with the aid of a food thermometer.
Mine did not involve the engineering precision of the study: although I used a stopwatch, there was inevitably a delay of a few seconds when transferring from one pot to the other, and maintaining the temperature of the cooler water was a challenge.
Merely introducing eggs that had just been in boiling water caused an increase of a degree or two. (The researchers recommend starting at 28°C to alleviate this problem; they also recommend lightly scratching the shell at one end of the egg before cooking and stirring the eggs gently when they are in the cooler water— which, I’ll be entirely honest, I forgot to do.)
The result, though, was delicious.
The yolk was a rich golden color, the taste was flavorful, and the consistency was slightly soft without being in any way runny. For those who like their boiled eggs on the harder side, it might be a disappointment (for those folks, the researchers recommend increasing the temperature of the cooler pot of water), but it hit extremely close to my personal sweet spot.
Why develop this recipe?
The researchers work at the university’s FoamLab, where they specialize in the structure of materials at various temperatures and under different conditions.
Their primary focus is plastics. But lab director and study co-author Ernesto Di Maio told National Geographic that they embarked on this project when “I was challenged by a colleague to adapt our work to more popular stuff, like food.”
The same colleague informed Di Maio of a chef who “sells his eggs for 80 euros each” and uses a technique that involves cooking albumen and yolk separately before “combining the two again after cooking, in a rather fancy way.”
Suitably challenged, Di Maio tasked PhD student Emilia Di Lorenzo to devise a method that could subject both parts of the egg to their ideal temperature during the cooking process while leaving the shell and contents intact.
Di Lorenzo approached her task the way any good materials scientist would: long before she conducted any real-world tests, she spent several weeks running computer simulations, modeling the heat transfer from water through shells into the heart of the egg, searching for a temperature and time combination that would allow both albumen and yolk to cook to the perfect consistency.
“We wrote a proper mathematical model,” Di Lorenzo explained. “And then we took the equation that we wrote and developed a computational fluid dynamics program. ‘What if we cook them at 100 degrees Celsius? What happens?’ And so on.”
It was only after a few months that Di Maio discovered that Di Lorenzo “doesn't like eggs at all. So, I was torturing her with this project.”
He, on the other hand, had no such qualms and made some for his family last Easter, “and they were amazed by the taste.”
In addition to the eggs’ perfectly cooked white and yellow parts, Di Maio, Di Lorenzo and colleagues found that eggs cooked by their method contained higher nutritional values across the board than those cooked by other methods.
Their goal ultimately was not to patent a new egg-cooking method but to conduct a fun thought experiment, one that showed, as they wrote in their paper, that “knowledge of the science behind simple problems can improve even the slightest bits of our daily life, like the simple act of eating an egg.”
