I got this tip from my mother, she says it helps bring calcium into the stock and break down the bones so the marrow can come out.

It seems like it would change the taste but I'm not sure how. Also it seems like the best way to get the marrow into the stock is to break the bones. I've had to use pliers and a cleaver to make that happen though, especially with turkey thigh bones.

3 Answers 3


One study found that:

  • "The stocks with and without vinegar did not differ in calcium content and all were poor sources of calcium, providing from 6 to 11 mg of calcium per cup"


  • "In contrast to the soup stock, one quart (four cups) of skim milk provides 1,184 mg calcium".

While another concluded that:

  • "prolonged cooking of a bone in soup increases the calcium content of the soup when cooked at an acidic, but not at a neutral pH"

In summary:

The cooking of bones in an acidic soup can (relative to a neutral soup) increase the calcium content provided that the cooking is for an extended period, however the calcium increase is minor/negligible, therefore vinegar-based soup stock should not be relied upon as an important source of dietary calcium.


  • Calcified Tissue International 1994 Jun; 54(6):486-8


  • Journal of the American Dietetic Association, Volume 89, Issue 12, December 1989


  • References, love it
    – jcollum
    Mar 8, 2022 at 18:16

These folks suggest that a couple of tablespoons of vinegar will help break down cartilage, and aid the development of a more gelatinous stock. I looked at a couple of chicken stock recipes. Many add a tablespoon or two, to 6 - 8 quarts water. I don't think you would taste the vinegar in this ratio. I'm not sure it is about marrow, but the intention is to extract collagen. Sounds reasonable, but whether or not it is happening when you make stock is less than clear. I have not found any studies that closely examined this.

  • A couple tablespoons of vinegar in 6-8 quarts of water seems negligible to me.
    – GdD
    Mar 5, 2022 at 15:07
  • 1
    @GdD...yup...and much more would probably impact flavor, that's is why I am suspicious of any real benefit.
    – moscafj
    Mar 5, 2022 at 17:14
  • also it seems like a very minor change to the acidity -- but maybe enough to matter without changing the flavor
    – jcollum
    Mar 7, 2022 at 17:35
  • @GdD 5-8% acetic acid in vinegar (presumably w/v) in general, so in 2 tbsp (30 ml) = 1.5 g = 0.025 mol in 5678 ml (6 qt) = 0.000004403 mol/l = 4.403 micromol/l. This isn't enough to extract much in the way of calcium. pH 5.444, so mildly acidic. I think collagen more affected than bone in this instance.
    – bob1
    Mar 8, 2022 at 7:20
  • 1
    @NeilMeyer you'll need to have a source for that to convince me
    – jcollum
    Mar 8, 2022 at 18:15

From personal experiments, while adding a small quantity of vinegar to the broth doesn't give a strong flavor necessarily, it's a flavor/aroma that still seems readily identifiable. Obviously, plenty of people are perfectly happy with adding vinegar, so YMMV.

If you intend to experiment, I'd consider using any acid you'd happily add to a soup over vinegar. Lemon juice, tomato paste, some sauerkraut brine, or a splash of wine would all add some acidity without the potential for an off-putting vinegary taste or smell.

That said... It sounds like you're chopping the bones..? If so, have you considered using a hammer to simply crack the bones instead? If I were so committed (which I admittedly am not), I'd be inclined to put a dish cloth over the bones and just beat on them. With a long simmer, a few solid cracks should be enough. But that's also point where YMMV.

  • I have better luck with pliers for making a crack in the bone then using a cleaver to open it up all the way. Hammer and a dish towel seems helpful but you'd get bone chips embedded in your dish towels, no?
    – jcollum
    Mar 9, 2022 at 19:22
  • @jcollum I get all kinds of things embedded in my dish towels lol (one reason I buy the cheap ones), but usually they shake out easily enough. You might use tea towels if you're worried about any Terry cloth/textured fabric that's more likely to snag.
    – kitukwfyer
    Mar 9, 2022 at 22:11
  • ooooh I have silicon sous vide bags, those things are pretty much indestructible, I use them for pounding down chicken breasts all the time
    – jcollum
    Mar 10, 2022 at 0:50

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