Boiling an Egg

When I was at university I had an organic chemistry tutor whose answer to every difficult question about solvents or reagents was, ‘Nick, don’t worry about it, it’s just cooking.’ How pleased I was then to read an article entitled ‘Chemistry really is just cooking’ (http://bit.ly/l30YF). One particular part of this article caught my eye, and that was how to boil an egg. I love eggs cooked in a variety of ways (for those interested there is a very good guide to poaching eggs here http://bit.ly/Knz5Z), but I had never heard of a way to make a boiled egg easier to peel. So in the name of science I tracked down two eggs, and gave it a go.

The article suggests that boiling eggs in an acidic solution makes them harder to peel than those boiled in an alkaline environment. I decided to make the experiment fair I would boil two eggs for three and a half minutes, one with 2 tablespoons of vinegar in the water, and one with a tablespoon of bicarbonate of soda in the water (bicarb makes the water alkaline – solutions contain the hydroxide ion as well as carbonic acid). I then timed how long it took me to peel the eggs.

In the end the results were much better than I was eggspecting (sorry, couldn’t resist). The picture below is the peeled egg cooked in vinegar. It was a nightmare to get the shell off and I gave up after two minutes with egg yolk all over my fingers.

The egg boiled in bicarb on the other hand was much easier to peel. The shell came away in large chunks in less than a minute, and in the end I had a perfect soft boiled egg. The only downside of this is that the article was correct about the smell – boiling eggs in this way does give off quite a distinct sulphur smell. The alkaline solution reduces the stickiness between the shell and the egg itself making the egg much easier to peel.

Verdict: A great quick experiment to do in the kitchen, and at the end of it you get to have lunch. More eggciting experiments to follow.