I've done a fair bit of reading about this question, most notably when I suddenly ended up with 90 quails' eggs and was trying to figure out how to cook them properly. I also really, really hate chalky yolks.
The basic problem is this: an egg has 3 significant types of material, each of which reacts differently to heat, and furthermore time is a significant factor that is not entirely aligned with temperature. Then there's the whole peeling problem, to which nobody seems to have found really effective solutions.
3 Materials
An egg has yolk, loose white, and tight white. If you crack an egg into a sieve, the loose white is the stuff that runs through easily, leaving behind the tight white and the yolk. The older the egg is, the more of the white that is loose, because of a steady shift in pH, as well as drying and some other factors.
Tight white begins to set at 140F, and is perfectly gelled at 145F.
Loose white sets quite slowly, and only holds its shape properly once it reaches about 160F.
Yolk begins to get thick at around 145F, and becomes fairly firm at 150F.
Time
However, all of this is affected by time, most dramatically with the yolk, and least dramatically with the loose white. In other words, if you cook an egg in an immersion circulator at 145F for 30 minutes, the tight white will be just set, the loose white will be liquid, and the yolk will be indistinguishable from raw. Take that to 45 minutes and the yolk will be beginning to thick. Take it to several hours and you can get the yolk to set -- but the whites won't change noticeably. If you want a really weird result, try cooking an egg at 145F for 24 hours or more: you'll get a little more firmness in the whites, though not much, but the yolk will go chalky and greenish!
Approaches
One standard approach, advocated for example by J. Kenji Lopez-Alt of The Food Lab, is essentially to ignore the loose white. You cook your eggs at 145F for 45 minutes, leaving a nice tight white and beautifully runny yolk. When you peel the egg (carefully!), much of the loose white will run off. The resultant
oeuf mollet is rinsed in ice water until needed.
The advantage of this approach is that it's simple, for one thing. Beyond that, it is often (but not always) the case that the liquid loose white creates a kind of buffer zone between the membrane on the shell's interior and the cooked egg, making peeling easier. Unfortunately, sometimes you get the opposite result, and so far as I am aware, there is no way to ensure the former rather than the latter. The disadvantage, of course, is that you're throwing away a certain amount of egg white. Not that it's all that wasteful, but it does make the eggs a little irregular in appearance.
Another approach, with which I've been experimenting, is to "blanch" the egg in rapidly-boiling water for 1 minute, then chill it in ice water for 15 minutes or so to bring it back to fridge temperature. Then cook the egg in the bath at 145F as before. The thing is, most of the loose white is on the very outside of the egg, because the tight white is contained within a soft, fragile membrane, and the loose is what is not so contained. When you put the egg in very hot water, the loose white is briefly exposed to a great deal of heat, bringing it up toward setting temperature (160F). Since egg gelling is not thermo-reversible, when you drop the egg into ice water, the loose white remains semi-set, but the rest does not cook. Then you cook at 145F as before, leaving a completely set white and a runny yolk. I have found that, for reasons I'm not quite clear on, this setting process also seems to make the loose white detach from the membrane on the inside of the shell, making peeling easier -- but again, it doesn't work every time. When it does work, you have a perfect peeled egg, except that the inside is liquid and the white isn't at all rubbery.
Questions
A. I have not yet sat down and worked out a clear experimental protocol for testing the "blanching." The basic question is obvious enough: how long does it take for the loose white to set, or come very close (let's say, 155F)? How long does it take before the tight white gets over 145F, and thus becoming firmer than desired?
B. Experiments by many other people have demonstrated that:
- Pricking an egg with a pin into the air chamber does not prevent cracking. It does, however, prompt the whites to act as a sort of bandage if there is cracking.
- Old and fresh eggs do not consistently peel differently. It is true that old eggs dry out somewhat, and there is a pH shift, and this does tend to pull away from the shell membrane. But all theory aside, exhaustive peel-tests show that eggs peel or don't, and age doesn't have any consistent effects.
- Boiling eggs in acidulated water does not make them peel more easily. It can soften the shell slightly, but not to such a degree that it has practical effects on peeling.
All that being the case, is there any way to improve your chances of a perfect peel?
C. Some people claim that steaming in a pressure-cooker works, the theory being that the high pressure contracts the air chamber and thus causes the egg to become smaller inside the shell, which when combined with the gelling gives you a partly-released egg. Whether this is true or not, there is a real problem with the method, in that you simply cannot expose an egg to a pressure-cooker environment briefly: it takes time to come up to pressure, even with rapidly-boiling water, and it takes time to depressurize, and all of this is relatively uncontrolled and uncontrollable. You may be able to get decent hard-boiled eggs this way, but I am skeptical about perfect
oeufs mollets.
D. If it can be established how long it takes for loose white to set at boiling temperature without setting the white, can we then derive from this a formula for the rapidity of energy movement across the egg contents, from outside in? If so, you should be able to calculate, within a relatively small margin, how long to cook quail or duck eggs.