Doneness is a gauge of how thoroughly cooked a cut of meat is based on the colour, juiciness and internal temperature when cooked.
Blue rare: at this point the beef has been seared on both sides over high heat, with the interior remaining mostly raw and intensely red. The core temperature ranges from 46°C to 52°C. It’s chosen particularly by European and North Americans.
Rare: slightly more cooked than blue rare, this point is characterized by having about 75 percent of the meat remaining raw. The core temperature ranges between 52°C and 55°C.
Medium rare: this is the preferred degree of doneness as the cut retains its juices. Seared, the 50 percent of the meat remaining red. The core temperature ranges from 55°C to 60°C.
Medium: At this point the meat loses some juiciness and flavor. Only about 25 percent has pink color. The core temperature ranges form 60°C to 65°C.
Medium well: here, the steak is almost totally cooked except for a sliver of pink at the center. The core temperature ranges from 65°C to 71°C.
Well done: at this point the meat is completely cooked, the outside is grayish, as it’s cooked over a low heat for a longer time, while the interior is brown. The cut losses about 70 percent of juiciness and can even become tough. The core temperature exceeds 71°C.