# how does the poaching eggs recipe scale for different sizes of egg?

The recipe for poaching regular chicken eggs states to leave the egg in a pot of simmering water for ~4 minutes (besides of messing with the liquid pH levels).

I was wondering how the temperature, pH and the time would change for eggs of different sizes, e.g. quail and ostrich ?

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I don't have an answer ... but I do have a source. I used to own a copy of "Good Things in England: A Practical Cookery Book for Everyday Use : Containing Traditional and Regional Recipes Suited to Modern Tastes Contributed by English Men and Women Between 1399 and 1932" by Florence White. I recall that it had a table of cooking times for swan, goose, duck, (ordinary) chicken, bantam, and quail eggs. The times were clearly derived empirically, not from thermodynamic theory! – user02814 Mar 26 '13 at 10:04
I once poached 300 quail eggs for a rather ill conceived brunch dish. They had set fully after 2 minutes although I cooked them to four with no ill effect due to strict water temp. I didn't realize that I could only cook them two minutes until about 100 eggs in. None of my diners could tell the difference. I'd post an answer but I have never cooked any of the larger eggs with this method. – sarge_smith Mar 27 '13 at 0:49

## 2 Answers

As stated above in various comments it is a complicated question. I do have some info.

First read khymos I think that the formula they have answers the question :-) They have a answer in a graph but it is only displayed for a very small range of chicken eggs.

This page in Norwegian gives you a online tool to manipulate the size of the egg and get the cooking time, but it only handles 12 to 17 cm circumference, translation here for the terms here if you need it

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It doesn't really scale since the thermodynamics of objects interacting in liquids is a differential equation. You may be able to make some gross assumptions and use a first order d.e. to estimate, but it wouldn't be an easy scale. You can get a more clear answer at http://physics.stackexchange.com.

However, the good folks at El Bulli solved this already.

• Place the eggs in a Sous Vide bath at exactly 63C 62C.
• After 1-hour you're gauranteed to have soft-boiled style eggs (shell or poached)
• After 1-day (they said) you'll still have soft-boild eggs. According to their testimony (it was presented at Harvard), you can run this indefinitely and not ruin the eggs.
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why the downvote? – Dan Mar 25 '13 at 23:23
Presumably the op wants to know about all those "complicated thermodynamics" rather than being told to just cook them another way. – Yamikuronue Mar 25 '13 at 23:39
Personally I'm dubious about your assertion that it doesn't scale. I find it hard to imagine that the heat transfer from water to egg is substantially qualitatively different when the eggs double in size. I would not be at all surprised if, assuming things are reasonably controlled (enough water, temperatures in the right place, etc), it scaled roughly with diameter/thickness - all that really has to happen is heat propagating through the egg. Do you actually know for a fact that as you vary the egg size, things change radically? – Jefromi Mar 25 '13 at 23:58
Surface area per volume is basically 1/radius. It really is probably roughly some power of the radius, even if my first guess wasn't right - but all that is kind of beside the point; it's probably a smooth continuous function, from a minute for quail eggs to four for chicken eggs to something bigger for ostrich eggs, and that function can certainly be characterized empirically if no other way. "The physics is complex" isn't really the same as "this isn't answerable". – Jefromi Mar 26 '13 at 1:58
That all being said, the OP isn't clear about what is needed for an answer. Eggs of different sizes will clearly cook differently but eggs from different animals also have varying thicknesses of shell which will play a factor as will starting temp of the egg and for the larger eggs the amount of water the egg is being poached in. – Brendan Mar 27 '13 at 1:46