![Meat thermometer](https://upload.wikimedia.org/wikipedia/commons/6/6c/Meat_thermometer.jpg)
Doneness is a gauge of how thoroughly cooked a cut of meat is based on its color, juiciness, and internal temperature. The gradations are most often used in reference to
beef
Beef is the culinary name for meat from cattle (''Bos taurus'').
In prehistoric times, humankind hunted aurochs and later domesticated them. Since that time, numerous breeds of cattle have been bred specifically for the quality or quantity ...
(especially
steak
A steak is a thick cut of meat generally sliced across the muscle fibers, sometimes including a bone. It is normally grilled or fried. Steak can be diced, cooked in sauce, such as in steak and kidney pie, or minced and formed into patties, ...
s and roasts) but are also applicable to other types of meat.
Gradations, their descriptions, and their associated temperatures vary regionally, with different cuisines using different cooking procedures and terminology. For steaks, common gradations include ''rare'', ''medium rare'', ''medium'', ''medium well'', and ''well done''.
Temperature
The table below is from an American reference book
and pertains to beef and lamb.
The interior of a cut of meat will still increase in temperature by after it is removed from an oven or other heat source as the hot exterior continues to warm the comparatively cooler interior. The exception is if the meat has been prepared in a
sous-vide
Sous vide (; French for 'under vacuum'), also known as low-temperature, long-time (LTLT) cooking, is a method of cooking in which food is placed in a plastic pouch or a glass jar and cooked in a water bath for longer than usual cooking times (usu ...
process, as it will already be at temperature equilibrium. The temperatures indicated above are the peak temperatures in the cooking process, so the meat should be removed from the heat source when it is a few degrees cooler.
The meat should be allowed to "rest" for a suitable amount of time (depending on the size of the cut) before being served. This makes it easier to carve and makes its structure firmer and more resistant to deformation. Its water-holding capacity also increases and less liquid is lost from the meat during carving.
Color
![Prime Rib cooked rare](https://upload.wikimedia.org/wikipedia/commons/9/98/Prime_Rib_cooked_rare.jpg)
As meat is cooked, it turns from red to pink to gray to brown to black (if burnt), and the amount of
myoglobin
Myoglobin (symbol Mb or MB) is an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue of vertebrates in general and in almost all mammals. Myoglobin is distantly related to hemoglobin. Compared to hemoglobin, myoglobi ...
and other juices decreases. The color change is due to changes in the oxidation of the
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
atom of the
heme
Heme, or haem (pronounced / hi:m/ ), is a precursor to hemoglobin, which is necessary to bind oxygen in the bloodstream. Heme is biosynthesized in both the bone marrow and the liver.
In biochemical terms, heme is a coordination complex "consisti ...
group in the myoglobin protein. Raw meat is red due to the myoglobin protein in the muscles, not
hemoglobin
Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...
from blood (which also contains a heme group, hence the color). Before cooking, the iron atom is in a +2 oxidation state and bound to a
dioxygen
There are several known allotropes of oxygen. The most familiar is molecular oxygen (O2), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (O3). Others are:
*A ...
molecule (), giving raw meat its red color. As meat cooks, the iron atom loses an electron, moving to a +3 oxidation state and coordinating with a water molecule (), which causes the meat to turn brown.
Searing
Searing (or pan searing) is a technique used in grilling, baking, braising, roasting, sautéing, etc., in which the surface of the food (usually meat such as beef, poultry, pork, seafood) is cooked at high temperature until a browned crust fo ...
raises the meat's surface temperature to , yielding
browning via the
caramelization
Caramelization is a process of browning of sugar used extensively in cooking for the resulting sweet nutty flavor and brown color. The brown colors are produced by three groups of polymers: caramelans (C24H36O18), caramelens (C36H50O25), and c ...
of sugars and the
Maillard reaction
The Maillard reaction ( ; ) is a chemical reaction between amino acids and reducing sugars that gives browned food its distinctive flavor. Seared steaks, fried dumplings, cookies and other kinds of biscuits, breads, toasted marshmallows, and man ...
of amino acids. If raised to a high enough temperature, meat blackens from
burning
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combusti ...
.
Drying
Well done cuts, in addition to being brown, are drier than other cuts and contain few or no juices. Note that
searing
Searing (or pan searing) is a technique used in grilling, baking, braising, roasting, sautéing, etc., in which the surface of the food (usually meat such as beef, poultry, pork, seafood) is cooked at high temperature until a browned crust fo ...
(cooking the exterior at a high temperature) in no way "
seals in the juices", since water evaporates at the same or higher rates as it does in unseared meat. However, searing does play an important role in browning, which is a crucial contributor to flavor and texture.
Safety
The
United States Department of Agriculture
The United States Department of Agriculture (USDA) is the United States federal executive departments, federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, ...
has stated that rare steaks are unsafe to eat. It recommends an internal temperature of at least for cuts of beef, veal, and lamb in order to prevent
foodborne illness
Foodborne illness (also foodborne disease and food poisoning) is any illness resulting from the spoilage of contaminated food by pathogenic bacteria, viruses, or parasites that contaminate food,
as well as prions (the agents of mad cow disease) ...
, and warns that color and texture indicators are not reliable.
The same meats should be thoroughly cooked to when ground or tenderized by cutting, since these processes distribute bacteria throughout the meat.
Usually, most bacteria do not enter the inside of uncooked meat and remains on the surface. However,
proteolytic
Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called proteases, ...
bacteria are able to dissolve or break down the connective tissue and fibers of the meat and enter the inside. Non-proteolytic bacteria such as
''Escherichia coli'' do not enter inside the meat.
See also
*
Pittsburgh rare
A Pittsburgh rare steak is one that has been heated to a very high temperature very quickly, so it is charred on the outside but still rare or raw on the inside. The degree of rareness and the amount of charring on the outside may vary accordin ...
References
Further reading
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Cooking
Meat