Starting at around 10 to 15 minutes, the brine formed by the salt dissolving in the meat's juices will begin to break down the muscle structure of the beef, causing it to become much more absorptive. The brine begins to slowly work its way back into the meat.
By the end of 40 minutes, most of the liquid has been reabsorbed into the meat. A small degree of evaporation has also occurred, causing the meat to be ever so slightly more concentrated in flavor.