There is a popular belief that the liquid released by meat when cooking is due to it being of poor quality or having been treated with hormones to increase its volume and weight. This is usually not the case. The reality is that it is a natural process, and if we end up seeing how the steak seems to overcook in the pan while it fills with a light brown liquid, it is because we are not cooking it properly.
That water is part of the musculature of animals, including humans, representing between 60 and 75% of the total. This is because the proteins found in animal musculature are much larger than the water molecules they contain, up to ten times larger. This causes the connections between those molecules to leave gaps large enough for the water to pass through. When subjected to heat, the molecules contract and expel water.
After butchering the meat, water remains in it and drains out whether it is raw or cooked. In fact, if it takes a while to get from the butcher to the house, or if it is purchased packaged in a supermarket, it usually starts to release a reddish liquid that we mistake for blood. It is actually a combination of water and proteins. One of them, myoglobin, is similar to hemoglobin and has the same red tone. It is what gives the appearance of blood by coloring the water that is released, and even its iron-like smell. This is the liquid that provides juiciness to a steak or roast, because the proteins it contains act like a sponge and retain some of the juice, coming from the fats.
More water in homemade frozen foods and meat products
The tone of myoglobin, like that of the meat itself, varies during cooking, which is why rare meat has a reddish juice that becomes clearer and more brownish when well done. However, the most efficient way to know if it is done to perfection is by using a thermometer. Many factors come into play in this process, determining the amount of liquid the meat contains. The species and age of the animal, the amount of retained fat, the upbringing and diet, the cut of the meat, and how it has been handled are some of them.
It is also worth noting that it releases a lot more liquid if it has been frozen at home, because the process is slower than if it is done in industrial refrigerators. The ice crystals that form are larger and break the muscle fibers that retain water, so a greater amount is released. There is also more liquid in prepared meats, such as marinated or roasted chickens, for example, due to the salt or stabilizers and preservatives added to them. On the other hand, the longer it is kept in the refrigerator after slaughter, the less water it will retain and the more tender and flavorful it will be.
Aging meats: Older is better
Hence the trend of consuming what is known as mature or aged meats, with a much more intense flavor, which have been aged for almost two months from the slaughter to the consumption. As the meat ages and is handled and cut, it loses its ability to absorb and retains less liquid.
In any case, the longer the meat is kept in the refrigerator, the more tender and flavorful it will be. For the most common type of meat, it is recommended that it be kept for at least 5 to 7 days before being put up for sale. If it is done earlier, it will be much tougher because it has not yet gone through the rigor mortis following the animal’s death.
The color of the juice that is released depends primarily on the moment when the animal started to be fed. If it starts at a very young age, as it happens with pigs or calves, they have less myoglobin in their muscles compared to when they are fed at a later age. The liquid is then more pink and becomes dark red in older cattle. The juice changes color when cooking the meat because the water evaporates, and that is one of the reasons why a hamburger or a steak shrink once cooked.
The amount of liquid that meat releases depends on the temperature at which it is heated. If it is cooked above 70 degrees Celsius, it can dry out because it becomes overexposed to air, causing the liquid on its surface to evaporate.
Temperature does matter, a lot
Connective tissues, such as tendons and ligaments, contain large amounts of collagen that makes the meat very tough. Collagen starts to denature at around 60 ºC, causing the fibers to compress, release liquid, and shrink. However, starting at 71 ºC, it begins to dissolve and turns into a rich juice that adds flavor and a tender texture. It is a mixture of peptides and proteins that are produced when collagen breaks down. It is water-soluble and forms a kind of gel when cooled, which we know as gelatin.
The denaturation of the collagen molecule is a kinetic process and therefore depends on both temperature and cooking time. If the meat is cooked at low temperatures, it will take much longer to liquefy. Elastin, which is more common in older animals, is a yellow connective tissue that does not break down when cooked. It is mainly found in ligaments and in smaller amounts in tendons. Meat containing elastin is typically considered lower quality.
Do you fry or recook?
The key to prevent water from invading the griddle or the frying pan is to ensure that they are very hot when placing the steak. Cooks know if the griddle is at the right temperature more by listening than by looking, because the meat makes a particular sound, caused by the water molecules coming into contact with the surface. If the steak is added too early, that’s when the phenomenon occurs where the pan fills with a light brown water and it seems like the steak is boiling in it.
Achieving a toasted tone and a crispy texture on the surface of meat is known as searing. By providing it with high heat, a layer is formed that largely prevents juices and fats from the interior from escaping. That dark tone is due to a series of chemical reactions that occur between amino acids and sugars, a sort of caramelization. These reactions take place at over 140 ºC, a temperature only reached through roasting or frying.
If the temperature is lower, water will not evaporate (which happens starting at 100 degrees) before detaching from the meat, and that chemical reaction cannot occur. However, other aspects must be taken into account to make the perfect steak. An expert tip is not to cook them right after taking them out of the refrigerator. It is much better for them to be at room temperature. If they are cold, the outside will toast, but the inside will remain more raw than desirable.
One should never poke the steak with a fork to see if it’s done enough, because all that does is make it lose all its juices, just as pressing it with a spatula does, as that way the fat, which adds richness and flavor, is extracted. Another bad practice is flipping it over and over again. It’s not necessary. Once per side is enough.
