Sealing meat is not essential

Q: At college we have been taught that "sealing" meat to retain the juices before cooking is a basic principle of cookery, but our science and technology lecturer says this is rubbish. Which is right?

Science wins over tradition in this case. The theory behind sealing meat goes back to Victorian times, when the idea that juices were sealed into a piece of meat by applying heat to the surface came from surgeons who believed it was the same principle as cauterisation, where blood-flow can be stopped by applying heat to an open wound. The two are similar, but do not achieve the same result.

There is not that much blood in meat when it arrives in the kitchen. Most of the fluid content is water and there is not enough blood to form a clot. This has been proven in laboratory conditions by comparing weight loss in the same amount of sealed and unsealed meat.

The main value of sealing is in the caramelisation of the meat juices around the outside of the meat, which improves the meat's flavour.