Why does bone soup often foam when cooking?
Even though you have thoroughly washed the bones and other ingredients, during the simmering process, the pot of bone soup still has a layer of foam emerging. Why is that?
Many people do not understand why bone soup often foams when boiling, even when they have paid great attention to cleaning the ingredients. Is the rising foam a sign that the bones have chemical residue during the raising or storage process?
The reason why bone soup often foams
Meat has two main components: protein and fat, in addition to water, carbohydrates and other substances. When stewing bones or boiling meat, these substances, along with excess blood and dirt on the surface of the meat, will be released, creating a bubbling phenomenon.
Why does bone soup often foam when cooking? (Photo: Mosaic Lille)
According to Associate Professor, Dr. Nguyen Duy Thinh, former lecturer at Hanoi University of Science and Technology, in fact, the foam that appears when boiling meat or stewing bones is not a sign that the meat or bones are toxic or that pigs are raised with chemicals.
That layer of foam is the amount of protein dissolved in water, then coagulates and floats when the meat and bone broth begins to boil. That foam may contain some of the dirt in the meat and bones. “During the process of slaughtering, transporting, and preserving, meat and bones are contaminated with dust, soil, and sand, but it cannot be confirmed that the meat is contaminated with chemicals ,” Associate Professor Thinh said.
Knowing that the reason why cooked bone soup often foams is not necessarily due to chemicals, so do we need to remove the foam? The answer is yes, because when protein precipitates, remaining impurities in the food are also mixed with it and coagulate. However, you only need to skim the first layer of foam when it shows signs of overflowing, the next layers of foam will not need to be skimmed anymore because by then the dirt has been removed.
The second layer of foam contains a lot of protein and bone fat and is clean so there is no need to skim anymore (Photo: Umami Days)
To remove dirt from bones when you first buy them, it’s best to wash them with diluted salt water, then rinse them thoroughly under clean water before putting them in a pot and adding water.
How to stew bones quickly, the broth is clear
Depending on the number of bones, the type of bones and whether you will reuse the bones or not, we adjust the cooking time. In general, to cook bone broth deliciously and quickly, you should follow these steps:
– Cut the bones into bite-sized pieces, wash them, and soak them in diluted salt water for 30 minutes to remove the fishy smell. Continue rinsing with clean water to remove excess blood and retain important nutrients, making bone soup more delicious and sweet.
– Put the bones in a pot with cold water, heat until boiling, stir once, then take out and wash. If you put bones in boiling water, the bones and dirt will immediately shrink when exposed to heat, causing many dirt in the bone marrow to not secrete and float. They will cloud the pot of bone broth and cause bad odors during the stewing process.
– Start stewing the bones in boiling water over low heat for 1 hour. When the stew is enough, add the fruits and vegetables and then add salt. Adding salt at this time will help make the soup clearer.
Treat cloudy broth
If the broth is unfortunately cloudy, you can handle it by:
– Put one egg white in a bowl, beat it and then pour it into the pot of broth, constantly stirring. A few seconds later, the black foam will blend into the egg white. At this point, you take the egg white out and the water will be clear.
– Put a few shiitake mushrooms or a few slices of raw potato into the pot of broth.
– With chicken bone broth, add new chicken bones and continue to simmer, the broth will be much less cloudy.
