Puréed stock turns white???

Discussion in 'Food & Cooking' started by chrislehrer, Oct 21, 2017.

  1. chrislehrer

    chrislehrer

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    In another thread (https://cheftalk.com/threads/xanthan-gum-sauce-white.95382/#post-569344) I was struggling with xanthan gum. Now the mystery is deeper and more serious.

    I made stock by roasting and then pressure-cooking a turkey carcass. Strained and chilled, it is medium-brown, mostly clear, and semi-gelatinous: it pours, but is definitely syrupy.

    If I heat this to a simmer, remove from heat, and start puréeing with an immersion blender, it foams up creamy white almost immediately. Once foamy, it doesn't settle out without lots of time and fine straining.

    Any theories?
     
  2. brianshaw

    brianshaw

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    Air. Just like taffy goes white when air is introduced by pulling.

    Does it return to brown after sitting?
     
  3. chrislehrer

    chrislehrer

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    Veeeeeeeery slowly. 10-15 minutes.
     
  4. chrislehrer

    chrislehrer

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    And I've never seen stock do this before.

    NOTE: We moved about 7 months ago, including shifting from town/reservoir water to a well.
     
  5. chrislehrer

    chrislehrer

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    Anyone have experience with hard water and the resultant soap residues? (My current theory...)
     
  6. Pat Pat

    Pat Pat

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    Hard water is not gonna do that to your stock. Air is the culprit like the others say.

    To avoid the whole pot of stock turning white, you can just blend part of the stock with the xanthan gum to disperse it, and then stir that into the rest of the stock.
     
  7. chrislehrer

    chrislehrer

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    Don't know if this will help, but when I puréed a block of the stock that I gelled lightly with agar, it did not foam or whiten.
     
  8. Pat Pat

    Pat Pat

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    Improperly skimmed stock can also turn white easily too. Fat and water will emulsify, trapping in the air better than if no fat is present.
     
    azenjoys and pete like this.
  9. pete

    pete Moderator Staff Member

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    Pat Pat said exactly what I was thinking-too much fat left in the stock.
     
  10. chefbuba

    chefbuba

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    Yep, same thing happens if you boil a stock with lots of fat, it will emulsify.
     
  11. House_Of_Game

    House_Of_Game

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    ???
    Mostly caused by boiling the stock instead of gently simmering..!
     
  12. chrislehrer

    chrislehrer

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    OK, an update. The stock was pretty clean, but the gum was very old. In addition, technique note: don't blend in xanthan gum if the stock is cold, or it will bind to the gelatin. Warm the stock until it's above about 80C and that problem goes away.
     
  13. chrislehrer

    chrislehrer

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    The plot continues to thicken.

    Made a brown turkey stock, mildly gelatinous, very little fat. Then I ice-filtered it: freeze solid, wrap in cheesecloth, allow to drain into a deep bowl very slowly in the refrigerator for 2-3 days. The result is essentially consomme: no noticeable gelatin in the mouthfeel, no fat whatever.

    Heat to a strong simmer, insert immersion blender, and... creamy.

    Yes, it's air. When I pour the stock into a big measuring cup and leave to stand, I can watch the foam slowly separate from the stock. Eventually, I skimmed off the foam and have perfectly clear (slightly xanthan-thickened) stock again.

    But what on earth is making it do this? There's no fat, and very, very little gelatin. I could serve that stock as consomme and I assure you nobody would question that it had been expertly clarified.

    I continue to believe that there is something in the water which is somehow causing this problem. Not that I think it's poisonous or something, but I would really like to know what's going on.
     
  14. cheflayne

    cheflayne

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    The immersion blender is the air culprit.
     
  15. brianshaw

    brianshaw

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    I think you are overthinking this one. It’s the manipulation, not the water.

    Thicken your gravy using a spoon, or gently with a whisk if you must.
     
  16. chrislehrer

    chrislehrer

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    Wait--I thought xanthan gum had to be dispersed ultra-evenly, with a whisk at the very least. Not so? How do I avoid "dumplings"?
     
  17. brianshaw

    brianshaw

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    Xanthan gum is not good for that application, as you are finding out. Thicken with a starch - flour, cornstarch, potato starch or arrowroot.
     
  18. chrislehrer

    chrislehrer

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    I'm lost. If xanthan gum isn't good for thickening liquids, what on Earth is it good for? Every source I've seen points to xanthan gum as an especially stable and easy-to-use thickener for sauces and the like. Now you say that's all wrong?
     
  19. brianshaw

    brianshaw

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    Best for emulsions, like salad dressing. Not bad for sauces like Vierge. But not so much for gravy.

    Others may have differing opinions. I’m mostly trying to help you grapple with your problem of air in your sauce.
     
  20. Pat Pat

    Pat Pat

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    I use xanthan gum to stabilize whipped cream and to thicken gravies.

    Are you using normal tap water? Where do you live? Maybe there's some kind of dissolved minerals in the water that create some chemical reactions?