For those who want to become rabbis, they will have to learn the laws for koshering meat! One can find these laws – known as the laws of melichah in the second section of the Shulchan Aruch – Yoreh Deah in chapters 69-78. There’s really a lot of material to go through, especially when one learns (as one should) with the nosei keilim (the main commentaries i.e. the Shach, Taz and other authorities).
What exactly goes into the kashering process? The short of it is that it is forbidden to eat the blood of an animal (see Leviticus 19:26 and Deuteronomy 12:23). The Torah tells us that the soul of the animal is inside its blood. When one consumes the blood, one brings into oneself even stronger forces of the animal soul than one already has. As a result, this causes actual changes for the way we think. We are what we eat – the saying goes! Eating the blood of the animal brings into us further animal-like qualities – especially those of the animal we are eating! Of course, irrespective of the changes this has for us as people, there is a mitzvah (commandment) not to eat the blood of an animal. Whether we can apply logic to it or not, is completely unnecessary. We fulfill the mitzvah – because it is a mitzvah and the will of God.
In order to remove the blood, we must salt the meat. However, salting itself will not succeed in our intended purpose, if we do not first clean the meat – washing it with a good wash for around half an hour. After applying the salt in accordance with halachah (after that wash), we are required to wash off the salt which has now become salt with absorbed blood. Thereafter, the meat is fitting to be eating.
There are of course hundreds of laws that one must master in order to understand all the situations that can occur, and mistakes that can happen – with us wondering if we have indeed kashered the meat as is fitting! This is the main subject of the law of melichah, and in it, one will learn all the laws for salting all the parts of the meat of an animal.
Below is a short video showing some of the practicality of kashering in general with a short interview from someone actually working in this area. Enjoy!