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Jan 15, 2011 12:23 PM

Brines: The science behind it doesnt add up!

The process behind what fuels a brine is what's known as osmosis.

Osmosis is the flow of water molecules to and through a semi-permeable membrane from a hypotonic environment (water with less salt) to that which is hypertonic (water with more salt).

Thus following this procedure, would ONLY succeed in draining water molecules OUT of the meat and into the salty briny solution, diluting it just a BIT, NOT as to anything going back INTO the MEAT itself! Nothing in this scientific explanation goes into explaining why or even IF the meat itself takes up any solution at all!

So what a brine SHOULD result in is an even DRIER piece of meat-- that even if it DID take up any brine solution, would be extremely salty at best.

Something isnt adding up here!

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  1. All the explanations I've read (Cook's Illustrated, etc) say that initially the water is drawn out of the food being brined but then the process reverses and the liquid, now including salt and other flavorings, is drawn back into the food. Obviously something of the sort is happening, as flavored brines penetrate throughout the meat (or whatever) that is bathed in them.

    1 Reply
    1. re: greygarious

      Does CI have the science behind why it "reverses"?

      1. re: Jennalynn

        But does the meat dilute the brine enough in order to reach an ionic equilibrium or reversal in order to go back INTO the meat again?

        I doubt that it does.

        Would seem that the dilution wouldnt be enough to reach equilibrium, let alone reverse the salt concentrated environments.

        If this were to work, it assumes that once the first osmosis happens with the molecules traveling from the meat to the solution, that the molecules dilute the brine enough to now make THAT (the brine) more hypotonic (containing less salt) than the inside of the MEAT (which would now become hyPERTONIC). And considering the amount of salt put into the brine to begin with-- the inside of the meat would have to be VERY concentrated in order for this to be true.

        So much so, that we should be able to stick that same piece of meat into plain water, and have it soak it up.

        and I'm not sure I've EVER heard of this happening.

        1. re: achilles007

          If you read jaykayen's link you will find the explanation.

          1. re: achilles007

            If you watched the video, Alton and his expert say it does reach equilibrium.

          1. re: jaykayen

            Hmmm.. very interesting.

            So by that notion... one could put a proportionate amount of salt onto a meat until the protein became denatured in then throw it into whatever sauce, solution of choice and the meat should drink it up?

            I wish the article would go into explaining the reverse-osmosis though.

            It describe the capacity of the cells becoming bigger in being able to hold more water once the proteins unravel, but doesnt describe the reason for why the water would see the need to enter into the meat cells.

            hmmmm... must marinate on this. No pun intended.

            1. re: achilles007

              Nowhere does it say that the cells become bigger, or that water needs to enter the cells. You must get the idea of cells/osmosis out of your head, because it doesn't have to do with osmosis.

              1. re: jaykayen

                "Nowhere does it say that the cells become bigger".

                Well, yes- I guess in an argument of semantics, it literally doesnt, but the "shape of the proteins" unraveling and relaxing from the protein sheaths thus allowing MORE room for water, is basically the same argument.

                1. re: achilles007

                  i figured the water went into interstitial regions, NOT cellular membranes, which remain intact. am I wrong?

          2. More general explanation here (beyond just as it applies to brining).


            2 Replies
            1. re: ipsedixit

              This Steamykitchen link discusses salting beef, not brining. There was a discussion on ATK last week the made a distinction between the two, claiming that salting is appropriate for beef, but brining is not. Beef does not need the added water, where as pork and chicken can benefit from brining.

              1. re: paulj

                I understand that.

                But it's essentially the same principle.

            2. Well, close but no cigar.
              Let's assume that the fibers in the meat contain no salt; only water.
              If we place salt into solution with water, the salt is evenly distributed in the liquid (water)
              When we place the meat into the liquid solution, the water in the meat mixes with the salted water of the brine and the two liquids combine to allow, albeit not as salty a solution as the initial brine itself, (which has now been diluted somewhat by the liquids in the meat) the meat fibers to gain salt molecules which in and of themselves hold (bond with) water. The salt molecules replace some of the water molecules which, in effect, actually holds moisture because fewer of the water molecules are available for direct evaporation during the cooking cycle. Salt reduces the rate of evaporation when in solution with water, thereby making the meat more moist.
              Most of my students don't care why it works; they just know that it does work and the results (if it's done properly) can be quite impressive.

              4 Replies
              1. re: todao

                Okay, I was right with you up until near the end of your fourth sentence.

                WHAT allows the meat fibers to gain the salt molecules?

                1. re: achilles007

                  A few things.

                  The ions in salt (sodium and chloride) could likely diffuse across the muscle cell membrane, thereby entering the cell itself.

                  Like todao said, you would have an equilibrium between the solutes in the brine and in the meat, due to an exchange diffusion. It's more about diffusion than osmosis after a bit, actually.

                  You end up with meat that has less water, and salt embedded within. Why is this good? Due to a few different reasons, maybe. In grilling or roasting, you've already seasoned the inside of the meat, and have less water overall, like dry-aging, and you would thus have a more concentrated flavor.

                  In boiling or braising, perhaps the denaturing of proteins contributes to the cooking process (after all, you're just denaturing proteins and coagulating them as you cook), but without the liquod within the meat escaping as much because of a reduction of cooking time. In hypothetical example, a meat that's 50% already denatured from salt would take less time to cook.

                  Disclaimer: I am not a professional cook/chef by any means.

                  1. re: xIcewind

                    Salts cannot diffuse into cells...they can only cause water to diffuse out of cells. Presumably though, the salty water can diffuse into spaces, such as between skin and meat, and into the pores of skin. I would guess (and I'm talking poultry here) that the salt draws water out of the skin while diffusing into the pores, openings where feathers were pulled, spaces between skin and meat...adding flavor. During roasting, melted fat penetrates the skin more easily because water was removed...and the skin gets a better texture because it lost water. People also air dry poultry to get a good texture in the skin.

                    1. re: EricMM

                      Salts cannot diffuse into living cells with intact lipid membranes. But salts have no problem getting into the cells of dead meat, especially after a bit of membrane damage caused by exposure to a hypertonic solution.