Cold boiled Eggs
Date: October 2007
Can you cook a egg in a cold beaker of water that is
boiling inside a vacuum?
Nope. You could boil it for days at room temperature,
and all it would do is grow deadly bacteria inside.
Same as it does sitting on the kitchen counter.
It takes a specific high temperature, measured in degrees C,
to kill germs or make the runny egg-white solidify.
The boiling action of water around an egg
is merely an easy accurate way to get a certain temperature
that happens to work pretty well for our cooking.
It only works repeatably because most of us live in 14.7 psi pressure.
It also helps guarantee the temperature won't go higher
and burn the part of the food closer to the burner.
Temperature regulation by boiling goes like this:
- If the water is lower than 100C,
the heat flowing in from the burner
causes the water to heat up towards 100C.
- If the water is 100C,
all the heat flowing in goes to
evaporating some water (as boiling bubbles),
and no increase in temperature occurs.
The bubbles stir the water pretty well too.
- If the temperature has somehow reached 102C,
part of the water erupts into steam
thereby promptly cooling the remaining water
right back down to 100C.
The eruption is of course quite dangerous
because of the 100C water it throws around.
For altitudes higher than sea-level,
substitute a temperature lower than 100C.
Boiled eggs at sea-level cook normally.
Boiled eggs at 8000 foot altitude cook slower.
Boiled eggs at 100,000 feet probably don't cook at all.
(But I don't think anybody's ever tried exactly that.)
The answer to your question is no.
What cooks an egg is heat, however you provide the heat. You can cook an egg
under the Sun, in a stove, on a grill, etc. You can also cook eggs in a pot
of water at temperatures well below the boiling temperature of about ~ 100 ?C.
It just takes longer to cook. If you cook it with water that is boiling hot,
it cooks faster.
So, it is not boiling that cooks the egg. It is the heat transfered from the
hot water to the egg that cooks it. As you know, there are many liquids that
boil well below the freezing point. So, an egg in such liquids (for example,
liquid nitrogen) actually freezes instead of being cooked.
Ali Khounsary, Ph.D.
Argonne National Laboratory
Cooking is a chemical reaction that happens above a certain temperature.
For example, an egg in the refrigerator will never cook no matter how
long it is left there.
Water boils at a lower temperature as air pressure falls because boiling
occurs when water is hot enough to turn to a gas despite the outside
pressure. That's why some cake mixes have "high altitude" directions;
folks living the mountains cook in pressure cookers and tea or coffee on
airplanes are never really hot.
It goes the other way, too. The higher the air pressure, the hotter the
water must be before it boils. You would have a better chance of
cooking your egg in an undersea habitat (high pressure) in water that
was not actually boiling.
Oklahoma State University - Okmulgee Campus
This is an interesting question! The answer is no, you cannot cook the
egg. When we cook an egg in the open atmosphere, we apply heat and it
is the application of heat that does the cooking, not the fact that it
is boiling. The vapor pressure of the water is related to the boiling
point of water and is also related to the atmospheric pressure. In
Denver, for instance, you have to cook an egg much longer because water
boils at a lower temperature. This is because Denver is 1 mile above sea
level and since the atmosphere is thinner, water will boil at a lower
temperature. Because cooking is performed by applying heat to a
particular food, the amount of heat matters. So if your water boils
at, let's say, half the temperature (50C instead of 100C), then you
would need a much longer cooking time to compensate for the lower
Now if we bring in a vacuum, the vapor pressure is very low and will
approach zero. This makes the water boil even though there is no heat
applied. Eventually the evaporation of the water will chill the water
down enough so that in a vacuum the water will freeze if outside heat
is not applied. So if you cannot cook an egg at room temperature, you
certainly can't cook an egg in ice ;) The main concept here is that it
is heat that cooks, not boiling.
Proteins, like those in eggs, are like carefully coiled up pieces of yarn.
Cooking egg proteins means adding enough heat to them that the yard uncoils
(scientists call this 'denaturing' the proteins). When the egg proteins
uncoil, they tangle up on each other and form the solid matrix that you know
as a cooked egg.
If you lower the pressure around the egg, but do not raise the temperature,
the water will 'boil', but it will not be adding heat to the egg. Therefore,
the proteins will not 'cook'.
Many liquids, as you probably know, will gradually evaporate away if left
out. This is because individual molecules of the liquid leave and become
gas. These gas molecules that come from the liquid exert a measurable air
pressure. If you put a liquid inside a vacuum vessel, then closed off the
vacuum, after some time, you could measure some pressure in the vessel. This
is called "partial pressure". The more volatile the liquid (volatile means
easier to evaporate), the higher its partial pressure. When the partial
pressure of the liquid is the same as the ambient pressure, the liquid
boils. Thus, the partial pressure of water at 100C is 1atm. If you lower the
ambient pressure, say to 0.9atm, then the water will 'boil' at a lower
temperature. If you lower the pressure enough, water will boil at room
Pressure can denature proteins too, but usually it's very high pressures. I
haven't heard of low pressures denaturing proteins. If you cracked the egg
first, I would guess that would not affect the egg proteins too much --
except that they would dry out in the vacuum pretty quickly.
You may know that egg shells are gas-permeable. They won't leak liquid, but
gas molecules can go through. Egg have a little gas-filled sac in them too.
If you change air pressure slowly, the egg can equilibrate (make equal on
both sides) the air pressure. However, if you put an egg in a vacuum very
quickly, I am not sure what would happen. Would the air pocket expand and
crack the egg? I'm not sure. Maybe you can try it. Reply back to let me
Hope this helps,
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Update: June 2012