The Gemara on today’s daf (=page) offers testimony about how this was done.
- Shmuel said: Meat cannot be drained of its blood unless it has been salted very well and rinsed very well.
- Rav Huna said: One must salt the meat and then rinse it.
- In a baraita it was taught: One must rinse it, salt it and then rinse it again.
- Rav Dimi of Nehardea used to salt meat with coarse salt and then shake it off.
In practice, the Rema rules (see Shulhan Arukh Yoreh De’ah 69:1) meat is first soaked in water for half and hour, or minimally rinsed well in water. Then the meat must be carefully salted with coarse salt. Finally, the salt must be washed off of the meat.
The Re’ah explains that the purpose of the first washing might be to remove any extant blood that is on the meat after slaughter, since the salt only has the power to draw out blood that is in the meat and is still wet; it does not affect blood that is on the meat that has already dried off. The Ran suggests that its purpose is to soften the meat and to remove dirt or foreign substances from it so that the salt can effectively draw the blood out of the meat. With regard to the final washing, the Ran explains that it is done in order to remove any excess blood that might remain on the meat.
The Rosh quotes two opinions about how to deal with meat that was not washed before salting. One possibility is that the salt would not effectively remove all of the blood, so the blood would be reabsorbed in the meat in a manner that would not allow it to be removed. The other possibility allows for a second salting that would remove all of the blood.