Let me start by saying that I hate being wrong but I’ll admit when I am. This time, I’m wrong. And I’ll have to admit it to my former sous chef next time I see him. Let me explain.
The last restaurant I worked at did Eggs Benedict with eggs that were cooked with an immersion circulator (*more details on circulators at the end of the post). I had always been under the impression that once the egg gets to the temperature of the water, it will not cook any further, meaning a 61 Celcius egg cooked for one hour will be the same as one cooked for three hours. Meanwhile, my sous chef would constantly push me to check the eggs to make sure they did not overcook. My belief of how eggs cooked stems from a seemingly logical, but incorrect, leap from how meat cooks in a circulator. A medium rare steak is medium rare regardless of how long its been cooked (though proteins in meats do break down over time, leading to textural changes). My sous chef had anecdotal evidence to back up his belief that an egg can overcook in a circulator and my retort against his claim was that the circulator needed recalibration.
With half a dozen eggs and a day off, I decided to test how cooking time affects the doneness of an egg. My point of reference as to how eggs should look after being cooked at a given temperature is Dave Arnold’s now ubiquitous egg chart. In the comments Dave Arnold notes that all his eggs were cooked for one hour and also that after one hour, change occurs only slowly. The latter comment, which I suppose I have conveniently ignored for the past three years, was a grave foreshadowing of how this experiment will end.
I started by placing six eggs into a 62C water bath. Every hour, I took one egg out to test for texture and doneness. I did this for five hours, a good amount of time for a brunch service, and I let the last one cook for 12 hours, for shiggles (that’s “shits and giggles”). According to the egg chart, the result I was looking for was a soft white and a yolk that flowed freely but with some viscosity.
Hour 1: White is barely set. Yolk is very loose. Undercooked compared to the 62C egg on the chart. Maybe because they were cold when I started the process.
Hour 2: White is soft and holds well. Yolk flows but has body. Matches the egg on the chart. If my theory holds true, the rest of the eggs should come out similar.
Hour 3, 4 and 5: Not much difference from the white in Hour 2. However, the yolk more resembles the 64C egg on the chart. Firmer, malleable, but still very creamy.
Hour 12: White is only slightly firmer than the white at Hour 2. The yolk is completely set with some granularity at the edge.
So there you have it. As it turns out, time is a significant factor in the cooking of eggs with an immersion circulator. If starting with cold eggs, I would recommend a cook time of about an hour and a half. If eggs are being held in the bath for service, it should be turned down to 60C to prevent overcooking. But the most important take away for me is learning to say “I’m wrong, and you’re right.”
* An immersion circulator is a device comprising primarily of a pump, a heating element and a temperature sensor. It is used to accurately and precisely control the temperature of a liquid bath (usually water, but I’ve seen people use beer). Food, a steak for example, is put into a bag, often vacuum sealed, and put into a water bath set at a particular temperature, 125F for medium rare beef. The steak can sit in a 125F bath for an indefinite amount of time and still be medium rare because the meat will never cook above that temperature. Many people use the term “sous vide” to describe cooking with an immersion circulator and those people are wrong. Sous vide is French for “under vacuum”, and more accurately describes the act of vacuum sealing the food rather than the cooking of it.