All about "sous vide" eggs

[DouglasBaldwin]

Thank you, Douglas, for your Egg cooking time table in post #28.

I did "perfect eggs" for the first time. The eggs had 14.0-14.5cm circumference, so at 75°C your table recommends 16 minutes.

With 16 minutes, to our taste the egg yolk was a bit overdone with just a small creamy center. So I tried 14.5 minutes, the yolk had remained creamy, rather a bit liquid, and the white was also a bit liquid, the eggs easily slided out of the decapitated shells. The third run with 15 minutes resulted in "the perfect egg" to our taste with a sufficiently firm yet soft white and a perfectly creamy yolk. So at 75°C it is really time-critical, and next time I'll start with 1 minute less than recommended in the table.

Fair enough. I generated a new table tonight with core temperatures from 60°C to 67°C so you (and anyone else) can get the yolk consistency you want.

EggHeatingTimes.pdf

[OliverB]

Hmm, so I had a box of free range farm fresh (well, bought last weekend) eggs and decided to go for the perfect egg in Baldwin's book, 148 degree for 45-60 min. And I was not impressed :-(

The white was partially set, partially a wobbly glibber, and the yolks were waxy, beyond the runny kind I expected to see. Almost as if the yolks had cooked more than the whites, which makes little sense of course. The eggs were out on the counter while the machine heated the water, should they be straight from the fridge instead?

The runny white was on the unappetizing side, so I dipped them into boiling water for a moment, the white was nicely set then, but they also were pretty impossible to peel.

I'll give this an other try, at an other temp, but if the results aren't any better I'll probably rather use the time/eggs/effort to improve on my real poached eggs instead.

Any idea why the yolk would be "overcooked" while most of the white was a runny (not clear) mess? Seems counter intuitive that the inside would cook faster than the outside.

PS: Baldwin's book is a must have, though the index should be reworked in a new edition. Looking up "Salmon" and just finding about 50 page numbers listed is not all that useful IMO. A minor thing, but to me a perfect index is what makes a perfect book. What ever that may be ;-)

Edited January 30, 2011 by OliverB (log)

[MartinH]

Any idea why the yolk would be "overcooked" while most of the white was a runny (not clear) mess? Seems counter intuitive that the inside would cook faster than the outside.

It is because they contain different proteins, which coagulate at different temps. In a sous vide bath there won't be any temp difference between inside and outside.

Perhaps expectations differ on what a "perfect egg" should be. Have a look at the photos on Douglas Baldwin's site.

I like to think of a 148F/64.5C egg as something unique, not a better or easier way to do a soft-boiled egg (with its firm white and runny yolk, which is "perfect" in its own way when done right), but instead a separate kind of cooked egg, another egg-style alongside scrambled, poached etc.

[OliverB]

forgot about that photo, thanks! That's more or less what I got, I was more expecting the 142 or 144 degree results, but was afraid the whites would be still clear and glibbery. I will have to try again. Perfect is of course a personal preference, I'd not call my result perfect by a long shot, unless I was only after very nice waxy yolks and discarding the whites. I guess I'll have to do one more experimental run at maybe 143 degree and see if I like the results, otherwise I'll be back at crating a vortex in a large pot of water with a dash of vinegar

[ScottyBoy]

Poached and SV'd eggs for me are two totally different applications. I can't bread and fry a SV'd egg...I can't use a poached egg to melt into a sauce for pasta after an awesome presentation with it whole on the plate.

From what you've been saying I might really suggest bumping it up to 145-46. Below that is very hard to handle and I find the white just a little too loose for my tastes. Good luck!

[MartinH]

[snip] I can't bread and fry a SV'd egg...

Well, maybe you can. Here's a way: take a 64.5C SV egg, wash off the white, roll the yolk in breadcrumbs, and fry briefly. Crunchy exterior with that rich custardy interior.

[ScottyBoy]

Oh sure, I use those custard yolks for all kinds of stuff but I'm just saying, a true poach is the only way to get that firm white that you can work with the whole egg.

[PedroG]

I did "perfect eggs" again using Douglas' new egg heating time table.

The eggs were 14.3-14.7mm in diameter, cooked 16 minutes at 75°C. The whites were soft with no residual liquid, the yolks were creamy at the center and a little bit firmer in their periphery, a perfect replacement for poached eggs.

Considering Douglas Baldwin's scientific explanations it is clear that a perfect egg with a soft yet firm egg white and a creamy yolk cannot be achieved by equilibrating for an arbitrarily long time in a 64.5°C water bath, but in a 75°C water bath it is a time-critical procedure to get the perfect "perfect egg".

Here's another way of suspending the eggs for fast and easy retrieval exactly at the right time:

[DaveJes1979]

Pedro, I think it would be critical to regulate the initial temperature of the eggs. Are you putting them in straight out of the fridge?

Edited February 10, 2011 by DaveJes1979 (log)

[PedroG]

Pedro, I think it would be critical to regulate the initial temperature of the eggs. Are you putting them in straight out of the fridge?

Yes, directly from the fridge, as specified in Douglas' first time table.

[rotuts]

I love the perfect poached egg, as everybody does.

I havent started with them yet

that being said, once we decide on the SV temp that suits us:

can a dozen eggs be done, cooled, placed in the refrig and very carefully brought up to temp later?

Id love to know how to do this!

cheers!

[Scout_21]

I rather enjoyed these instruction from Wylie Dufresne...though the first temp is in C and the second is in F. I made these a few weeks ago on a Saturday for a nice breakfast on Sunday but didn't want to deal with cooking the eggs while prepping the hollandaise and canadian bacon and I thought they were wonderful...and I never even cracked an egg to check on their texture. I would recommend cracking them into a bowl first after reheating to clean them up a bit before platting like he says in the article. I'd be happy to hear other people's successes or failures.

How to Cook an Egg, By Wylie Dufresne

Edited March 23, 2011 by Scout_21 (log)

[rotuts]

Whooooooooooooo!

thanks for your Time!

Im On the Way!

[vengroff]

I love sous vide eggs and until recently always used the slow cooking method. But I’ve been experimenting with 75°C water and have had some very good results. The most critical thing to know about the faster method is that when the center reaches the target temperature it is still moving up pretty rapidly, so pulling the eggs out at exactly the right time is critical. There are other factors that matter a lot too, like whether you use a circulating or non-circulating bath, and some that are far less critical, like the exact starting temperature of the eggs from the refrigerator.

I actually modified my iPad sous-vide dashboard a little bit to make the rising temperature effect really clear. Here’s a screen shot of the dashboard configured for an egg of 150mm circumference and 75°C water.

First, notice that in the graph the core temperature (the thick dark line) is still rising rapidly at the end of the cooking time. This means that if you leave the eggs in for an extra minute or so, their temperature will rise quite a bit relative to your actual goal. This is very much in contrast with the more common sous-vide approach that produces a nice soft landing at the target temperature by using a bath only 0.5-1.0°C warmer.

Exactly how fast the temperature will be rising at the end of the cooking time is given by the number 1.46°C/min., which tells us that if we leave the egg in an extra minute the core temperature will rise quite significantly.

In contrast, consider the lower temperature approach shown here:

In this case, the core temperature curve has the more classic shape where it slows down a lot as it reaches the target temperature. In this case, it is rising at only 0.13°C per minute. For larger eggs, this number will be even smaller. For large cuts of meat, like beef tenderloins, this number can be well below 0.1°C/min. at the point the meat reaches temperature.

If we look at what other factors can affect the outcome of eggs, we find that one of the most significant has to do with the type of equipment used. In the examples above, I had my dashboard set for a Polyscience Sous Vide Professional. If I switch to the Sous Vide Supreme, which does not have a powerful circulator, and go back to the 75°C method, things take longer because without circulation the water does not transfer heat to the food as efficiently.

The difference in time between the two machines is 2:40, which at a rate of approximately between 1.2 and 1.4°C/min. means a significant temperature difference. If I used the Sous Vide Supreme numbers for the Sous Vide Professional or vice-versa I would not get the results I hoped for. It is thus critical that I use times tailored to my specific machine.

Another factor that we might think would make a big difference is the initial temperature of the eggs. However, this does not make nearly as big a difference as the machine or the exact cooking time in the 75°C case. In the example below, I raised the initial temperature of the eggs from 5°C to 8°C and the cooking time was only reduced by 16 seconds. So food safety issues aside, you don’t have to worry much about your refrigerator not being adequately cold.

Finally, just as a test case to make sure my calculations are not off the rails, I duplicated some Douglas Baldwin’s table scenarios and got results to within a matter of seconds. For example, here is the case from his table for a 150mm circumference egg in 75°C water with a custom circulator somewhat more powerful than my Sous Vide Pro (h=200 W/m^2-K vs. 155 for the technically minded):

Douglas’ table says 17:10 for this case, whereas my dashboard says 17:12. I’m happy with this, as there are probably subtle differences in how we handle some of the technical details of the simulation that could account for a difference this small.

I was originally planning to just use this dashboard to fill in some gaps in the tables, but I’ve since found that by playing around with it I have gained a much better understanding of the dynamics of sous-vide cooking and what factors have the greatest influence over the quality of the results. I certainly expect to cook even better eggs in the future as a result.

[PedroG]

vengroff,

that's awesome!

Would you mind programming this for a common Windows-PC (Excel-sheet)? Or a Windows-Mobile-PDA?

Thanks

Pedro

[technophile50]

What about starting with a fixed volume of water at 100 deg C in an insulated (styrofoam?) container, to which you add an egg from the fridge, where the combined masses equilibrate to the desired yolk temperature (64C), but the gradient while it's coming to equilibrium firms up the white?

[lstrelau]

Vengroff, can't wait til this shows up on iTunes for my iPhone!

[vengroff]

Would you mind programming this for a common Windows-PC (Excel-sheet)? Or a Windows-Mobile-PDA?

Windows Phone could be an option in the future, but Excel is probably not. The style of simulation required doesn't lend itself well to a spreadsheet. It isn't just a series of formulas, but rather an iterative process where for each of a large number of very short time intervals from the time the food enters the water until it is done you have to solve a relatively large set of equations. I'm sure it could be done with some clever VBA, but it's not really the sort of thing Excel was built for.

Vengroff, can't wait til this shows up on iTunes for my iPhone!

I've got a small number of bugs to work through but I'll probably submit it to Apple in the next couple of weeks. We'll see from there how long the approval process takes. Initially it will be for the iPad, but I will also try to rework the UI for the iPhone.

Thanks to both of you for the support.

[vengroff]

What about starting with a fixed volume of water at 100 deg C in an insulated (styrofoam?) container, to which you add an egg from the fridge, where the combined masses equilibrate to the desired yolk temperature (64C), but the gradient while it's coming to equilibrium firms up the white?

I haven't seen exactly this proposal before, but I have certainly seen people advocate putting the eggs in cold water, bringing it to a boil, then immediately shutting it off and holding it for some number of minutes. The Joy of Cooking, for example, advocates this technique.

I suspect it is possible to come up with more than one water temperature over time curve that generates the kind of gradient you described to cook the white, then drops the water temperature to allow just the right amount of heat to reach the center of the yolk. If it can be done with a quantity of water at a fixed initial temperature in a well insulated vessel as you describe, that would be even better.

I have contemplated the non-constant water temperature approach for a number of applications, but I have never followed through. Mainly it's because I think it would require something more sophisticated than an off-the-shelf PID to control properly.

[yosemit3]

Has anyone tried to sous vide the eggs at the temp for their desired yolk consistency, then chill. Later, place them in a hotter bath, for a derived time to set the whites to the desired stage. I'm assuming there would be a small delay in the heat transfer from the white to the yolk. Then one could shock the egg in a cooler bath to protect the yolk. If one pasteurized the eggs in the first step, then you could store them, and reheat in an under 145F (serving temp) bath to serve any time. A lot of fiddling and variables, but may be worth the effort.

Disclaimer: I have several heated and chilled baths.

[rotuts]

I love the 'personally perfect poached egg'

SV eggs have the advantage as you pick the 'yolk temp' you love and then can SV a couple of dozen and you are set for a while.

"fresh eggs" where you get them and talk to the chicken are best as the albumen is very 'tight' these eggs will not work for anything that requires whipped eggs whites. they cannot be whipped correctly as they are too tight.

these eggs are best for SV but hard to find. in the Old Days one water poached the eggs and that solved the problem as the albumen that had stretched out was left in the water.

some say after you SV, you take a very short time in really hot water to set the white. havent tried this.

my SV eggs have a small amount of 'water' in them when I break them on toast. it might be water that entered the egg ( 60 min is a long time!) or albumen that had not set. i dont mind this on my toast. it softens it and allows me to use less butter I love butter but if you use it as a condiment you will have at least a few months more to enjoy SV before you Croak!

Try to find true fresh eggs. Still warm, Fresh form the Hen.! I have a source and will report back

Edited April 3, 2011 by rotuts (log)

[PedroG]

I did it again (four eggs of 143mm circumference, 75°C / 16 minutes), see upthread. The result was perfect, but one of the eggs must have had a slight crack that had gone unnoticed. It was just a little bit of egg-white that escaped, but what a mess! Cleaning the polycarbonate container and the FreshMealsMagic took me considerably more than half an hour. In the future I will do eggs only in my SVM-controlled stockpot without a circulating pump so eventual cleaning would be easier.

[DocDougherty]

Vengroff,

Great work. Reminds me of Nathanm's original approach using Mathematica. I trust you are solving Gauss in 3-D with an appropriate step size, so perhaps it would be possible to expose the heat transfer coefficient as an input variable so that those of us with Lauda circulators can adjust the model to accommodate variable pump speeds (or for other complications that make it different from your assumptions about the equipment).

Doc

[vengroff]

Vengroff,

Great work. Reminds me of Nathanm's original approach using Mathematica. I trust you are solving Gauss in 3-D with an appropriate step size, so perhaps it would be possible to expose the heat transfer coefficient as an input variable so that those of us with Lauda circulators can adjust the model to accommodate variable pump speeds (or for other complications that make it different from your assumptions about the equipment).

Doc

Thanks, Doc. I do provide an advanced customization screen that allows you to override all relevant input variables. You can use that to set the surface heat transfer coefficient as you wish between 50 and 1200 W/m^2-K. That being said, most users will rely on the built-in values tied to particular equipment that are chosen from the main setup menu. These include 95 W/m^2-K (Sous Vide Supreme), 155 W/m^2-K (Sous Vide Professional), and fixed values of 200, 300, and 600 (the values I most commonly see in the literature). If you happen to know the coefficients for the Lauda machine you have, please let me know and I'll be happy to add them. If you know them for the different pump speeds, so much the better.

The app is in beta now and should be publicly available in the app store soon.

[DocDougherty]

What about starting with a fixed volume of water at 100 deg C in an insulated (styrofoam?) container, to which you add an egg from the fridge, where the combined masses equilibrate to the desired yolk temperature (64C), but the gradient while it's coming to equilibrium firms up the white?

That is a very clever notion. And I am tempted to immediately start an inductive experiment, but a little back of the envelope analysis says that it is quite sensitive to losses (conduction, container mass and Cp, convection and radiation, etc). Making the approximation that Cp for an egg is 1.0, egg mass is 60 gm (large egg), the sensitivity to the mass of 100°C water is something around 0.5°C of final egg temperature per gram of water, not including anything for the as yet unspecified losses or their dependency on T(water) or T(egg) or ambient conditions, or container specifics. So while it should work, the degree of precision may be a little tough to deliver.

But I am going to try it anyway using a wide-mouth thermos liner and a double air gap for insulation and an initial assumption that the losses are about 20% of the total heat.

Doc