Would it be kosher to eat a steak that is cooked medium-rare? I ask because it seems that there is still blood that comes out of the meat when cooked like this. Should steak be "well done"?
The laws of kashrut require the extraction and drainage of all blood from beef or fowl within 72 hours of slaughtering. This is accomplished through a unique soaking and salting process—or, in some instances, through broiling.
The reddish liquid that remains inside the meat after this procedure is not halachically considered blood; it is the meat's "juice," and is 100% kosher.
Today, kosher meat is sold with the blood already removed. Therefore, if dining in a kosher restaurant, or if you bought your meat at a reliable kosher butcher, you can confidently eat your medium-rare steak.
Rabbi Baruch S. Davidson