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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.

              2. Tell you what achilles. You are obviously a scientific guy. Set up an experiment and a blind taste test. Make 2 pork tenderloins or two chicken breasts and treat them exactly alike except one gets brined for an hour and patted dry and the other doesn't. Season them both as you normally would.

                If you can't tell the difference, you get back to us. I think you will find a world of difference in both flavor and moistness. I'm a science kind of guy too and I wasted 20 years before I discovered brining.

                There are what seems to be dozens of articles describing how brining works. One of them has to be technical enough for you. Start googling.

                12 Replies
                1. re: Hank Hanover

                  I've done side-by-side comparisons a few times as I also have a scientific mind. Most recently I brined two bone-in rib chops (3 hours) and did not brine the others. Used the same glaze, cooking techniques, etc. There was a marked difference; my husband and I overwhelmingly preferred the brined chops. We've also done this with poultry, pork loin, etc. on different occasions and have always come to the same conclusion. The flavour is more pronounced and the meat more tender. Just be sure not to brine too long as the meat can become salty. Three to six hours for smaller cuts of meat is sufficient for noticeable difference and six to overnight for larger cuts.

                  My brines often use soy sauce instead of water/salt and a sugar component such as apple cider, maple syrup or brown sugar. Sometimes vanilla beans are included.

                  Totally agree with those who air dry poultry - the skin is much crispier than without air drying.

                  1. re: chefathome

                    I'm wondering....during the summer, I'm sometimes lucky enough to catch weakfish. If I don't release them, I give them to friends or my mother in law. I just can't stand the fish...flavor is great, but the texture is just way too soft. It occurred to me this summer that maybe brining the fillet's might toughen them up a tiny bit. Think that's possible? As it turned out, the heat set in this summer and the weakfish disappeared when the water got to warm, so I never had a chance to try out my theory.

                    1. re: EricMM

                      I can't help on the theory part, but if you like the flavor, why not go with the flow and use the fish for croquettes, quenelles, or seafood sausage (combine with diced shellfish or firm-fleshed fish for textural variety)?

                      1. re: greygarious

                        fish tends to just go to mush when exposed to liquid for extended periods. You could always try it, but I'm thinking that it would just get softer.

                        1. re: sunshine842

                          Yes - just think of ceviche. Lovely for awhile but the texture can change.

                      2. re: EricMM

                        brining sure gives better texture to farmed shrimp. worth a try

                        1. re: scubadoo97

                          That's definitely true. Sometimes I also let my shrimp sit in seasoned buttermilk.

                      3. re: chefathome

                        But OP is talking about the pure science. I don't necessarily understand all of it :) but do find it very interesting. Plus I recently saw a term called "flavor brining." I think as opposed to doing it to tenderize. But that's probably another thread.

                      4. re: Hank Hanover

                        Also being scientifically inclined I propose a small addition to this experiment. Weigh the pieces of meat before and after brining (also weigh the unbrined controls). Provided you have a precise and accurate scale you should be able to detect a small increase in the weight of the brined meat.

                        1. re: kmcarr


                          This link from serious eats has a brining science piece like you are talking about. The chart shows the turkey brine gained almost 5% in weight from the brine

                            1. re: ESNY

                              Thanks for the confirmation ESNY. And that article should go a long way towards answering the OP's questions.

                        2. Below is an explanation geared toward engineers. Give it a read


                          1 Reply
                          1. A brined turkey thigh tastes pretty good. Don't know the science behind it, just know it's kick-ass good. Leftovers remain moist, too. Too salty? No, not even close.

                            1. Okay, to summarize what I think that I have read here:

                              1. Some people argue that brining draws moisture out of the meat because salt attracts moisture. However, after a while, a salt and water combination move back into the meat, due to the scientific principal that equilibrium must be maintained. That is, the ratio of salt to water must be the same inside the turkey (or whatever) as the ratio of salt to water is on the outside of the turkey.

                              2. But wait, say other people. All you have done is replace non-salty water with a salty water (brine) in the cells. So the net result is that the turkey's cells now contain more salt and less water than they did before you started the brining process. This is not a result which should make the turkey moister. After all, less moisture is less moisture.

                              3. Other people say that the reason brined meat seems moister than non-brined meat is because brined meat fibers have been caused to relax, due to one of the mysterious properties of exposure to salt. This relaxation of the meat fibers means that there is more space between the fibers into which brine may travel. (That is, you have actually created more space in the meat by relaxing the fibers.) Once trapped between the relaxed meat fibers, the brine stays there, mostly. Therefore, even though the meat contains more salt now, it also contains far more water. Hence, the meat is moister.

                              4. I am pretty clear about the arguments in paragraphs 1 to 3. However, I don't really follow the reasoning very well for my summary of the argument in paragraph 5 (below), and I am perfectly willing to have someone tell me that I misunderstood the argument in paragraph 5 completely.

                              5. Wait! say other people. You've got it all wrong. The reason the meat is moister is because the salt entered the cells, banged around inside them them, and sort of destroyed the interior surface of the cells. (Imagine a room in which there has been a fight, with all sorts of destroyed furniture, broken crockery, shattered mirrors, etc.) The substances from the interior surface of the cells are molecules which are too big to exit the cells, so they remain there in their destroyed states. Therefore, the meat is tenderized, due to partial cell destruction and the brine has more room (or something) to hang around in the partially destroyed cells.

                              I took my only chemistry course as a freshman in high school in 1965, so I await correction from you more scientific types. I'm just delighted that brining works.

                              1. Found this older thread while trying to use the internet to learn more regarding a brining method I read about in Modernist Cusine vol. 3 - that being "equilibrium brining". Here's their explanation of brining in general:

                                "Chloride ions, from dissolved salt, diffuse into muscle fibers and accumulate along the surface of protein filaments. As these ions increase in number, they generate a negative charge that loosens and pushes neighboring filaments apart -- analogous to the way magnets with the same polarization repel each other. The charged filaments push far enough apart that they cause the muscle fibers to swell -- if water is available to fill the space opened up in the process."

                                Here's a pretty good discussion on the three major brining strategies (but I didn't think the embeded video was worth watching):


                                This link - http://eater.com/archives/2011/02/17/...

                                - is an interview with Nathan Myhrvold, where he says,

                                "We have a completely different way of brining meat than most people use. We've invented a technique we call equilibrium brining. Most brining starts with a really concentrated salt solution and then you soak the food in that for awhile, and that makes the outside way too salty, except the inside isn't salty enough. So then you soak it in water for hours to try to leach salt out. And it's all very inexact. So we came up with a way where you can basically do foolproof brining. Use a much lower salt concentration and you let it sit for a longer period of time."