Problems will most definitely arise if the eggs are cooked at a temperature that is too high, if the eggs are not very fresh or if there is not enough water in the saucepan.
Use a saucepan or a deep frying pan, which allows you to fill it with about 3 inches of water. The eggs should be covered with water during cooking and the 3 inch depth of water ensures that the eggs will not stick to the pan.
Poached eggs must be cooked in water that is very gently bubbling or simmering. The water is first brought to the boil and then by turning the heat down on the cooker, is allowed to gently simmer. The eggs are carefully added to the pan at this point. If the water is boiling too fiercely, the eggs will be forced to move around too much, causing them to break up and lose their shape. A gentle simmer allows the egg to sit in one place throughout cooking and cook nicely.
By using the freshest eggs possible, eggs that are less than four days old, you are more likely to achieve a perfectly poached egg that keep its shape. With a fresh egg, the white will stay close to the yolk and should not spread out thinly.
Vinegar should be added to the water as it begins to boil, as this will help the egg white to coagulate more quickly and form a neat and compact shape. Without the vinegar, disaster may occur. Use about 1 tablespoon of vinegar for each pint of water. Bear in mind that the vinegar may slightly flavour the eggs, so do not use too much or a vinegar that is too strong if you are not so keen on a vinegary tasting eggs.
Poached eggs, as with fried eggs and soft-boiled eggs, should be cooked so that the white is set yet the yolk is still runny. For this, the eggs should be cooked for between 2½ - 3½ minutes depending on the size of the egg. If you want to check to see whether the poached eggs are done during cooking, carefully lift the egg out of the water with a slotted spoon and press the white with your finger. A firm and set white at the thickest part of the egg means that the egg is ready.
Once the eggs have been cooked they should be drained on kitchen towel to remove any excess water before serving, although if you are not going to use them immediately, they may be kept in the fridge in water for up to 24 hours.
If you are not going to use the poached eggs straightaway, undercook the eggs slightly and then store them covered in cold water in the fridge. To heat them up, cook them in simmering water for 1 -2 minutes when you are ready to serve and eat them.
Below is a simple method on how to poach eggs. Remember that if you are not successful on your first attempt of cooking poached eggs, do not give up, as when you do prepare a perfectly poached egg, it will definitely have been worth the effort and the wait.