Is This the Perfect Egg? Scientists Say 32-Minute Cooking Technique Reigns Supreme

Achieving perfection when cooking an egg is a matter of personal opinion and can be quite contentious.

Maybe you like a scrambled egg better than a hard-boiled one for breakfast. Perhaps poached eggs are more up your alley.

I lean towards a soft-boiled egg nestled inside a slice of bread—otherwise known as the burst-yolk sandwich—but achieving perfectly cooked both the yolk and white together can be challenging, often resulting in either overly done yolks or insufficiently cooked whites.

The quest for perfect eggs – achieving the ideal texture and taste when combining yolks and whites – could turn into an obsession, drawing in even scientists.

Today’s research reveals that a group of Italian researchers believe they've created a novel method for cooking eggs within their shells, achieving what they consider to be ideal consistency and flavor without compromising nutritional quality compared to alternative techniques.

The procedure detailed in the peer-reviewed journal Communications Engineering Referred to as the "cyclical egg," this process requires moving an egg, which weighs between 63 to 73 grams, back and forth every two minutes from boiling water to a bowl of lukewarm water at approximately 30 degrees Celsius over a duration of 32 minutes.

To uncover this technique, the research group from the University of Naples and Italy’s Institute of Polymers needed to address the primary challenge associated with boiling eggs: the fact that yolks and whites set at distinct temperatures.

Bridging the temperature gap

According to lead author Emilia Di Lorenzo, a materials and food scientist at the university's Foam Lab, the issue is that the ideal temperature for preparing the egg whites is 85°C, whereas for the yolk, it should be 65°C.

She mentioned that the process of cooking an egg essentially boils down to a matter of energy transfer.

So, how would you regulate the temperature for two distinct materials within one item to achieve the ideal cooking result?

Several current approaches nearly achieve this.

In Japan, the onsen tamago (hot spring egg) is cooked in its shell at temperatures ranging from 63°C to 70°C, resulting in custard-like whites and yolks.

In 2002, the culinary landscape of the Western world experienced a significant surge in interest when French physical chemist Hervé This introduced the concept of cooking eggs at precisely 65 degrees Celsius (also known as the 6X egg for experimenting with nearby temperature settings). The technique involves placing an egg inside a vacuum-sealed pouch before slowly simmering it in water heated to exactly 65°C, which gives both the yolk and whites a smooth, creamy texture reminiscent of custard.

In both the onsen and the sous vide at 65°C methods, the egg whites do not completely solidify as their proteins do not reach a sufficient temperature for coagulation. As a result, chefs frequently discard the still-translucent raw sections.

Ernesto Di Maio, who directs Foam Lab and is also a co-author of the study, mentions that certain chefs attempt to achieve firmer whites by cracking the eggs open and cooking each part individually, resulting in elaborate dishes he has witnessed being sold at prices as high as €80 ($123).

While having a drink with a coworker, they pondered whether their expertise in material science, particularly in foam structures and polymers, could be applied to tackle the issue at hand.

He mentioned that he has spent several years developing methods to endow materials with varying characteristics within the same object.

Whether it’s part of an aircraft wing or a component for replacing bodily tissue.

Ms Di Lorenzo stated that the team created thermal profiles to determine the necessary temperature shifts for accurately cooking both the yolk and the white of an egg.

Their computations indicated that the egg should cycle through phases of exposure to both warm and cool water, ensuring that the whites experience temperatures ranging from 37 to 100 degrees, whereas the yolks remain at 67 degrees throughout the cooking process.

Ms Di Lorenzo mentioned that there was an extra surprise when assessing the nutritional content of raw egg yolks as opposed to those that were hard-boiled, soft-boiled, and prepared using the 6X technique.

She mentioned that the level of polyphenols, which are beneficial micronutrients, was significantly greater compared to other methods of preparing eggs.

Additional studies are required to determine the cause of this phenomenon; however, Dr Di Lorenzo believes it could be due to the eggs being boiled at precisely the temperature where the proteins in both the whites and yolks begin to denature.

Dr This, from France’s National Institute of Agricultural Research and uninvolved with the research, mentioned that although the preparation technique seemed enjoyable, it had been previously executed.

He suggested that '[periodic cooking]' was introduced roughly a hundred years ago for meats, which were alternately placed in hot and cold water," he added, mentioning that he had previously attempted the method but found no additional sensory benefits.

He was equally taken aback that the study authors didn’t include microwave cooking or pascalization (high-pressure sterilization of food) for comparison.

How does it taste?

The periodic egg essentially features whites akin to those of softly boiled eggs and a yolk that resembles the 6X, which may require up to an hour of cooking time according to the study.

In the course of the research, a group of impartial testers evaluated periodic eggs against those boiled six times or more using conventional methods.

They found:

• Hard-boiled eggs were less wet, more adhesive and powdery compared to periodic eggs. The whites were sweeter, but the yolk less sweet and without as much umami.
• Soft-boiled eggs exhibited a glossier appearance in the white part but felt drier when eaten and lacked sweetness compared to traditional eggs. Additionally, the yolk was more moist, less sweet, and not as salty.
• The 6X eggs appeared significantly glossier and more translucent compared to the periodic eggs, offering a texture that dissolved more readily when tasted. However, the yolks remained quite alike.

However, Doctor This mentioned that the research utilized just one variety of hard-boiled egg, which can vary in how thoroughly it is cooked, and the issue with raising the temperature at 6X eggs was also highlighted.

He pointed out that it only referenced the sous vide 6X technique and failed to consider alternatives like using an oven or even a dishwasher as options.

Regarding how Ms Di Lorenzo feels about her work, this is what the authors have to say. , Who will receive a doctoral degree at the end of this month for their dissertation on cooking yeast-less pizza dough Actually isn't very fond of eggs.

Doctor Di Maio, nevertheless, considered the outcome remarkable.

He mentioned that it was enjoyable to hold it in his mouth and bite into it due to the excellent combination of texture and flavor.

I gave cooking a poached egg a try, and the consistency of the yolk was unlike anything I've experienced from a regular hen’s egg before.

It feels quite strange to bite into a runny yolk surrounded by solid boiled whites compared to previous egg encounters.

I envision tackling the refinement of this technique on a relaxed Sunday. However, considering the constant shuttling between pots, achieving a softly boiled egg appears much more straightforward.

Dr Di Maio mentioned that adjusting the timing and using non-boiling water temperatures might also influence the texture and flavor outcomes.

Meanwhile, he jests that he might begin selling periodic eggs for €100 ($165).

However, since the publication of the paper, the experimentation has been handed over to the general public and the hospitality industry.

The search for the ideally boiled egg goes on.