For something as seemingly simple as cooking a raw egg in
hot water, it never ceases to amaze me that so many people disagree on how best
to do it. The other week when I
was working at a French restaurant I was tasked with poaching a batch of eggs
to be deep-fried later on that day. When I began setting up three different
chefs told me three different and seemingly contradictory methods for egg
poaching. I became so intrigued by this that I tried all three and gave them
marks out of ten. Interestingly all three methods worked ok, but none of them
achieved a flawless result every time. I was also told a story by one of the
chefs about a time he worked in a kitchen in France and was ridiculed for
putting salt in the water. All the chefs at the restaurant claimed that “the
worst possible thing you could do when poaching eggs was to salt the water “but
none of them seemed to have a concrete reason as to why “ You just don’t,
simple as that” would seem to be the reasoning. So this English chef challenged them to cook 10 eggs there
way and he would cook 10 his way. In conclusion they found that both eggs
looked almost identical but both parties noted that the ones cooked in salt
tasted a little bit better.
It’s made me think a lot about egg poaching since. So I
decided to do a bit of research in to how many ways it can be done and how many
of those ways are actually any good.
I got to a point in my research where I now think I could easily do 50
different methods so I decided to stick the goalposts there.
Before I start though we need to look at how and why an egg
poaches and see what it is we are trying to achieve in each method.
The Science bit.
When we poach an egg we are cooking using a method of heat
transfer called convection. The heat in the water is transferred to the egg
whilst the two are in contact with each other. The benefits unlike frying are
that the water envelops the egg so it is far easier to get an even cook, and
because there is no oil involved the end result is a much healthier
alternative. In theory egg poaching can be seen as egg boiling without the
shell.
The difficulties in most egg cooking methods arise from the
fact than the egg is made out of two separate components (the white and the
yolk) and both of those components have different cooking times and
temperatures. Now I could go on here and give you a bunch of equations on
thermal heat transfers but I’m sure it would bore you to tears. What you do
need to bear in mind though is that both the egg white and the egg yolk begin
to cook in the 60-70oC temperature range and the egg white begins to cook
first. So therefore it makes sense to state that when we are cooking anything
egg based we need to at least cook above 60oC.
So why then if we don’t have t cook at the temperature of
boiling water (100oC) do most methods insist that the water is boiling or near
boiling? The reason for this is
because unlike a shell on egg, the poached egg does not begin a solid object, it
begins a liquid and the success of most techniques is based on us being able to
turn the egg in to a solid mass as quickly as possible to avoid us having our
egg spread itself all over the pan. Higher temperatures speed up the cooking
time meaning that the egg has to travel a shorter distance in the water before
it begins to cook.
What we are trying to avoid more that anything is the egg
hitting the bottom of the pan whilst still being a liquid. For this we need to
have one of the following.
- A
high enough temperature to cook the egg quickly.
- A big enough pan so as the egg has longer to travel and in turn more time to cook.
- A
slow speed in the water, which will again give us more time in which to
cook the egg.
Another important factor is the temperature of the egg
before we cook it. It would make good sense to say that the higher the
temperature the egg is before it hits the pan the less time again it needs to
cook. This is something you should bear in mind if you like me keep your eggs
in the fridge. I would recommend you take them out a while in advance.
Here’s an equation we can use (I accept not a very good one)
(T(e) + T(w) + D)/r+s= Xp
Where T(e) is the temperature of the egg before poaching
T(w) is the water temperature, D is the distance the egg can travel
uninterrupted, r is the radius of the egg and s is the speed at which the egg
is travelling in the water. Xp is then a number, which sort of determines the likelyhood of whether or not your egg will poach nicely or not. The higher the
number the more chance you have. Not very scientific but I really like having
equations.
Now we have our faux maths worked out lets get poaching and
look at the first method.
Oh one more thing before we do. My assumptions before this
experiment are that we are looking for:
a)
A firmish white with a runny yolk.
b)
A nice rounded compact shape.
c)
The yolk to be covered by the white and as central as
possible.