All about "sous vide" eggs

[DocDougherty]

A couple of eggless trials to calibrate the thermal losses showed that they are more like 65% of the energy required to cook the egg and are dominated by heating up the container (in this case a 16 oz widemouth thermos liner) followed by conductive losses through the cap/seal.

Because cooking time is quite long if you want to wait until everything gets to equilibrium, adding more hot water and stopping at a pre-calculated time seems likely to be an improvement.

Two runs with eggs uncovered and then confirmed/quantified a major temperature stratification issue. With a 60gm egg, 198gm of boiling water, and after 25 min of undisturbed cooking time there was almost 10°C of temperature difference between the top and the bottom of the water column (61.5°C at the bottom and 71.2°C at the top). A needle probe showed 66.8°C in the geometric center of the egg so the yolk should have been (over)cooked. But when it was sectioned through the center, the top half of the yolk was solid (the top was marked with a permanent marker) and the lower half was liquid. On average the egg was cooked.

So if this is going to work, there will need to be a mechanism to circulate the water (or the egg), and it will require some empirical modeling of the loss mechanisms which are a substantial fraction of the total energy required, and there will likely still be a desire to add a time component to get the precision. It might be possible to build the model that is well enough calibrated that a combination of end point water temperature and elapsed time correctly estimates the internal egg temperature.

Another approach would be to drop an egg into a water bath at a higher temperature and transfer it to a lower temperature bath after a fixed period of time, letting the heat propagate both in and out to finish cooking the yolk and to stop cooking the white. While it is still a 3-D problem, a 1-D approximation along with a calibration term might be good enough to deliver what you want.

Doc

[rotuts]

Re: cracks

as Pedro has suggested, from time to time I get a thin crack in my """SV""" eggs.

in the Dark Ages when i cooked mu eggs Darklleyy I understood that there was a small air sac at the base (the less round end) and if you used a Push-Pin that released the air that was there as the heat expanded it ..... so the eggs did not crack at those temps.

I thought of doing this with my """""SV""""" eggs then re thought that as I cool them water might enter and leave them less desirable and may not '''pastureized'''

so I just eat them!

eggs are enough to get anybody that loves egg into SV !!

not the same as those fried eggs with the crispy edges!~

Eggs for All!

[mgaretz]

vengroff - did your iPad app ever come out? I couldn't locate it in the app store.

Edited June 24, 2011 by mgaretz (log)

[Intellidepth]

vengroff - searched under 'sous vide' for your app in the store, couldn't locate it yet. I only have an iphone so keen for the alternative user interface What a brilliant concept.

[jaymer]

I looked at Douglas' pdf on egg cooking times.

I have to think that if a tiny .5 cm difference in circumference requires a 40-50 sec increase in cooking time (for example), then there's got to be an even greater difference in cooking 2 eggs or 8 eggs since the 8 cold eggs will greatly (i say greatly, but I have not measured it) drop the water bath temp initially.

Am i missing something? (like maybe I didn't read the entire thread)

Is the table for 1 egg at a time?

Whats the formula for scaling to multiple eggs?

For me personally, I'm looking for runny yellow - like Kyhmos @ 40 min

http://blog.khymos.org/2011/04/23/perfect-egg-yolks-part-2/#more-2897

thx

jaymer...

[PedroG]

Douglas' tables are for any number of eggs, if your water bath is not very small.

8 eggs may be about 500g.

In my PID tuning experiment (last post in the old SV topic), throwing an ice-brick of 560g/-20°C into a 15L water bath at 55°C resulted in a temperature drop of just 0.2°C for less than 2 minutes, so the temperature drop from 8 eggs (500g/5°C) will be negligible, at least with a well tuned system.

[Robert Jueneman]

Douglas' tables are for the classic single temperature model, as opposed to the more recent 6X egg technique that Martin Lerch and other have discussed (including myself, at http://freshmealssolutions.com/index.php?option=com_k2&view=item&id=65:search-perfect-egg-jueneman&Itemid=100088).

But what happens if something other than chicken eggs are used, say quail eggs, or perhaps duck eggs?

Duck eggs are about the same size as chicken eggs, but on the only time I tried them, I got vastly different results, so perhaps the different species protein matters.

And for quail eggs, there is both a different species, and a considerably different size, and perhaps a difference in the ratio of white to yolk, as well.

Before I waste time experimenting with them, has anyone already done this?

Bob

[shar999]

Received my machine today. I've spent the past week trying to read all the pages of the sous vide threads. It's overwhelming.

My question is: Eggs....can I place them in a zip loc bag without a vacuum to cook in case one breaks. If I can, do I have to fill the bag with some of the water?

[mgaretz]

Received my machine today. I've spent the past week trying to read all the pages of the sous vide threads. It's overwhelming.

My question is: Eggs....can I place them in a zip loc bag without a vacuum to cook in case one breaks. If I can, do I have to fill the bag with some of the water?

You could, by why bother? If one breaks, it isn't a big deal. Maybe a little more effort to clean up afterwards, but I have yet to break one, and I'm guessing it's more effort to bag them. Yes, you'd have to fill the bags with water and get as much air out as possible.

Think about this, do you bag eggs now to hard/soft boil them and they're out of the shells to begin with in regular poaching.

[vengroff]

Received my machine today. I've spent the past week trying to read all the pages of the sous vide threads. It's overwhelming.

My question is: Eggs....can I place them in a zip loc bag without a vacuum to cook in case one breaks. If I can, do I have to fill the bag with some of the water?

I would not recommend this, and I would definitely not put the eggs in bags filled with water. In general, you want the water to circulate freely around your food as it cooks. If there is water in a bag with the food then that water is not circulating around the bath back to the heating element.

I would not worry too much, though. I cook eggs regularly and breakage has never been a problem.

[Robert Jueneman]

Received my machine today. I've spent the past week trying to read all the pages of the sous vide threads. It's overwhelming.

My question is: Eggs....can I place them in a zip loc bag without a vacuum to cook in case one breaks. If I can, do I have to fill the bag with some of the water?

I would not recommend this, and I would definitely not put the eggs in bags filled with water. In general, you want the water to circulate freely around your food as it cooks. If there is water in a bag with the food then that water is not circulating around the bath back to the heating element.

I would not worry too much, though. I cook eggs regularly and breakage has never been a problem.

Vengroff, as one Chief Scientist/Amateur Cook to another, I have to strongly disagree with you. In my experience, as well a PedroG's, egg cracking is a quite common problem, and if you are using any kind of a circulator, a real PITA to clean up afterwards. I certainly don't want to ruin an expensive circulator for a minor inconvenience!

If the bag containing the eggs is filled with just enough water to cover the eggs in a single layer, and importantly, the water that you use is already up to temperature (having been extracted from the bath), any temperature differential is likely to be minimal. Your could of course test this by sealing a thermocouple inside the bag, using the Archimedes principle, and I confess that I haven't done so, but if it was more than 0.5 degree F I would be quite surprised -- astonished, in fact.

Bob

[PedroG]

Received my machine today. I've spent the past week trying to read all the pages of the sous vide threads. It's overwhelming.

My question is: Eggs....can I place them in a zip loc bag without a vacuum to cook in case one breaks. If I can, do I have to fill the bag with some of the water?

I would not recommend this, and I would definitely not put the eggs in bags filled with water. In general, you want the water to circulate freely around your food as it cooks. If there is water in a bag with the food then that water is not circulating around the bath back to the heating element.

I would not worry too much, though. I cook eggs regularly and breakage has never been a problem.

Vengroff, as one Chief Scientist/Amateur Cook to another, I have to strongly disagree with you. In my experience, as well a PedroG's, egg cracking is a quite common problem, and if you are using any kind of a circulator, a real PITA to clean up afterwards. I certainly don't want to ruin an expensive circulator for a minor inconvenience!

If the bag containing the eggs is filled with just enough water to cover the eggs in a single layer, and importantly, the water that you use is already up to temperature (having been extracted from the bath), any temperature differential is likely to be minimal. Your could of course test this by sealing a thermocouple inside the bag, using the Archimedes principle, and I confess that I haven't done so, but if it was more than 0.5 degree F I would be quite surprised -- astonished, in fact.

Bob

I totally agree with Bob:

Finagle's corollary to Murphy's Law says: Anything that can go wrong, will -- at the worst possible moment. (i.e. in a SV bath most difficult to clean).

Cleaning a SVS after breaking an egg may not be a very big deal, but in an FMM or IC you may need to use a professional grill-cleaning-solution containing sodium hydroxide to clean the mess. I did my last SV eggs in a skewer-suspended ziploc bag partly filled with hot water from the SV bath to displace the air, and the outcome was the same as with naked eggs in the bath.

[mgaretz]

Guess I am used to my SVS which cleans easy if necessary.

[blackp]

Guess I am used to my SVS which cleans easy if necessary.

It will clean easily, but has no chance of maintaining a constant temperature throughout the tank as well as a "stirred" bath. An impeller, pump or air circulation system will make sure that no matter where your eggs lie they will be at the same temperature. A square/oblong tank with a heater underneath cannot possibly have a consistent temperature without some form of stirring.

I agree with Pedro and Bob - Murphy does exist and a zip lock bag is a simple way to make sure that any eggshell fractures do not become a clean up problem.

Edited November 17, 2011 by blackp (log)

[rotuts]

after refining my technique Ive never had a cracked egg:

the egg cracks when the inner air pocket at the flatter end expands too quickly: a cold egg from the refrig into the hot SV solution might do it.

I either bring the eggs to room temp either by placing them in a hot water (tap) bath for a few minutes or bring to room temp slower.

\

you may notice if you try this tiny bubbles come out of the egg on the entire surface. this was a concern for me as when cooling i assumed the water went back into the egg.

but maybe not.

anyway, no more cracked eggs.

[vengroff]

Ok, you guys are right. I should test this before making a blanket statement. I've never seriously looked for a bagging solution to cracking because it is not a problem I have ever had.

The one thing I do, however, is put a pin prick in the air bubble end of the egg. I've done this for years for boiled eggs, long before I ever used sous vide.

[rotuts]

pin-prick works but I stopped doing it for SV as when you cool the egg, that hot air has to contract a little and pull water inside

this might effect the opened egg ie more watery and maybe effect the pasteurization if kept for a while.

id like someone to pls try the warm up method

many thanks

[vengroff]

This thread has been fantastically educational on the subject of cooking eggs in water baths. It's the first place I learned about the fast-cook method, which is now my go to way of cooking eggs in a circulator. I cook in 77°C water to a core yolk temperature of 62°C. It gives me the combination of relatively firm whites and a spreadable jammy yolk in 14 minutes, plus or minus depending on the exact size of the egg.

I've summarized what I learned here and elsewhere about the fast-cook technique and what has been incorporated into the SousVide Dash app in a blog post and video. I hope it is useful and interesting to you.

[slkinsey]

What are some good techniques for getting the firmed-white style of SV eggs out of the shell?

[vengroff]

What are some good techniques for getting the firmed-white style of SV eggs out of the shell?

I cut the big end of the egg off then insert a spoon between the shell and the egg white. I then spin it around the egg to separate the white from the shell on all sides. From there it usually pours out pretty easily. If it doesn't, I crack the shell a little more until it does. The key is having a spoon that is as close to the profile of the egg as possible.

[PedroG]

Cracked eggs and messed up SV rig

Expansion of the air bubble is not the reason that makes eggs crack. Air is a poor heat conductor and will heat and expand slowly, increasing pressure slowly by about 25% while heating from 5°C (278K) to 75°C (348K); remember Amonton's law aka 2^nd Gay-Lussac's law. Cracks happen shortly after immersing the egg in hot water, not at the end of the cooking time. Egg shells may sometimes have uneven thickness, so the thinner parts will heat and expand faster than the thicker ones, leading to tension cracks. Pricking the blunt end of the egg may lead to microscopic relaxing cracks thus avoiding macroscopic tension cracks.

Should you need to clean a messed up SV rig, the "professional grill-cleaning-solution containing sodium hydroxide" I mentioned upthread is "Johnson Diversey D9 SUMA Grill heavy duty oven cleaner"; the link has been removed because it was no longer valid. Anyway, preventing a mess by bagging the eggs is easier than cleaning, and suspending the bag makes retrieval easier.

[pep.]

I just re-read this thread because I'm holding a sous-vide presentation next week at the Foodcamp Vienna (sorry, German only). I'll prepare some sous-vide meat and vegetables to reheat and show different the textures, but the main event will be SV eggs. Has anyone tried genuine onsen-tamago? What would be the best temperature to approximate the texture? 63.5°C? I'd prefer to do it without delta-T to not be time critical (I can pre-cook the eggs at home or start them a bit earlier than the session).

[mkayahara]

I would check out the Ideas in Food book; they've got great instructions for onsen-tamago.

[Baselerd]

I tried the "Oeufs en meurrette" recipe from the Modernist Cuisine a few weeks ago. It's supposed to be a liquid center egg with a fully gelled white. The technique they tell you to follow is to boil eggs for 3-4 minutes in the shell, then cook in a water bath @143 F. The trick was ensuring the initial boil step fully gelled the whites while keeping the yolk fully liquid. My conclusion is that this is nearly impossible. I was able to achieve a good enough consistency, but was never able to get it just perfect. Leave it to boil too long and some of the egg yolk will begin to solidify. Boil too quickly and the white will remain runny, which is far less appetizing to me than having some solid egg yolks. In either case, I'm convinced that its near-impossible to have a perfectly cooked liquid center egg unless you find an egg with whites of uniform thickness...

Edited September 28, 2012 by Baselerd (log)

[Robert Jueneman]

See my blog at http://freshmealssolutions.com/index.php?option=com_k2&view=item&id=65:search-perfect-egg-jueneman&Itemid=100088.

The problem you are having, I believe, is probably due to your not chilling the egg immediately after boiling it. And unfortunately, this is one area where MC lets us down.

Try a three minute pre-boil directly from the fridge, then 63C for 125 minutes.

Then crack the egg with a egg-cutter.

Bob