NaCl (salt). Ionic bonds. Proteins. And why a brine makes meat juicier.
It is counter-intuitive. When we put food into a salt solution (i.e. a brine), the brine should draw water out from the food via osmosis, and make the food less juicy. But yet recipes clearly say a “brine adds flavor and keeps the meat tender and juicy” (see video below).
It is ironic, but true. And it all has to do with ionic bonds. In this case, it is the ionic bonds of salt, or sodium chloride (NaCl). The ionic compound NaCl is formed when Na atoms each give up an electron to Cl atoms.
The former become Na+ ions while the latter become Cl- ions. Each Na+ ion is surrounded by 6 Cl- ions, and each Cl- ion is surrounded by 6 Na+ ions (hence “ionic bonds”). Together they form a crystal lattice, giving us the chemical compound we call “salt”.
When we make a brine, we add salt to water. Water is a polar molecule: the hydrogen atoms are partially positively charged (∂+) while the oxygen atoms are partially negatively charged (∂-). The positive parts will envelope the Cl- ions while the negative parts will do the same with the Na+ ions. This will pull NaCl apart into Na+ and Cl- ions, thus dissolving the salt.
When we place meat like chicken or turkey into the brine, the water in the meat does indeed flow out via osmosis. But the Na+ and Cl- ions will also flow in (through diffusion) into the meat.
The meat proteins, which have a mix of positive and negative charges, will…
“…readjust their shape to accommodate the [Na+ and Cl- ions]. This re-arrangement of the protein molecules creates gaps that fill up with water.” (Source: Cook’s Illustrated – The Science of Good Cooking)
At the same time, the brine dissolves…
“… some of the muscle proteins (mainly myosin). The muscle fibers loosen up, allowing them to absorb more moisture.” (Source: Serious Eats)
The combined effect? Thanks to brining, there is more water in the meat and the meat is juicier. Even when we cook the meat and some of the water evaporates, the extra water ensures the meat will not dry out.
Besides the ions, you will also have noticed that diffusion and osmosis play a big part. Read more about their science and how they make meat crispy and juicy (another irony?) in the 1-Minute NomNom “The wizard of osmosis (and diffusion)“!
Like this? Like NaCl, we can make your life juicier with knowledge, so like me to discover more. All you need is a minute a day to explore the world’s marvels through the phenomenon of food!
photos: in order – depositphotos/lenyvavsha; kastarisentra; logos2012; rob3000; popov26