I get asked this alot and it’s quite simple but sometimes hard to do when you are in a hurry and feeding a family who have commitments and other issues. As meat is cooked the proteins called myoglobin, in the meat heat up and set. The more cooked the meat, the more ‘set’ the proteins have become.
This is why we can judge a piece of meat’s readiness by prodding it with tongs – the firmer the meat, the more ‘done’ it is. When the proteins set they push the meat’s juices towards the centre of the meat.In all of the cooking shows we see them almost squeezing the sides of meat, this is doing the same thing, if it springs back quickly it is cooked rare to medium rare. If it springs back slowly you probably have cooked to a medium colour – where juices will still move out of the steak and provide it to be tender. If it is hard then you have cooked a medium well, if it maintains the pressure points you will have coked a well done steak and there will be no transfer of juice through the meat.
Allowing the meat to stand away from the heat before serving allows the juices, which have been driven to the centre of the meat to redistribute throughout the meat and be reabsorbed. As a result the meat will loose less juice when you cut it and be far more tender and juicy to eat.
Most people mistake the meat juice for blood, as it will come out of the meat after it soaks through, it will appear red in colour and will seep out of a piece of cooked meat. The Myoglobin is a protein that stores oxygen in muscle cells, very similar to its cousin, hemoglobin, that stores oxygen in red blood cells. This is necessary for muscles which need immediate oxygen for energy during frequent, continual usage. Myoglobin is highly pigmented, specifically red; so the more myoglobin, the redder the meat will look and the darker it will get when you cook it.