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Mar 19, 2012 08:42 AM

Prague powder and all purpose cure

I came across some cures buried in the bottom of one of my fridges. Question is, does anyone know if they expire? Iknow they are basically salt with nitries or nitrates. Just curious.

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  1. So the question is do preservatives preserve themselves? I'd vote "yes."

    1 Reply
    1. re: ferret

      ferret, thanks for your response, and yes it makes sense. Maybe I should have asked if nitrates and nitrites become more or less volatile over time. Dry curing can be risky business. Also, am I overthinking the issue?

    2. Sodium nitrite slowly (over a period of years) oxidizes in air to sodium nitrate.

      5 Replies
      1. re: drongo

        drongo, thanks for your response. I understand the transformation of nitrite to nitrate, but I didn't realize it was exposure to atmosphere. I was under the impression the change had to do with the reaction between proteins and moisture. Either way, I just was wondering if my stored curing salts were still usable. I have a whole bunch and if it is still valid, why buy more? Of course, if I contact the source, I'm sure they'll tell me to throw it away and buy all new....... from them. Hoping there is someone who can speak to the issue of if nitrites and nitrates expire.

        1. re: teflontom

          I'm a scientist in my "day job"... and we have sodium nitrite in the lab with a shelf life of 2 years at room temperature (and in practice it would last much longer). If your curing salts are dry, I think they'll be fine.

          If you're comfortable doing serial dilutions, you could test them for both nitrite and nitrate content using aquarium test strips (though maybe the test strips would cost you more than replacing the curing salts, lol).

          1. re: drongo

            dr, thanks for the info. I've decided to toss the old (they were from '06) and I ordered fresh stuff. I am curoius though, what exactly is the reaction of the slow cure for dry aging vs. the "cooked or smoked cure " other than the fact that the # 1 contains only nitrites and the # 2 contains both nitrites and nitrates in very disparate proportions. My understanding was that when # 1 was smoked or slow cooked that the nitrates became nirites. If you clarify for me I would be very appreciative. I'm no scientist, but I did work as a metallurgist in labs for 25 years. Hope I didn't get off point.

            1. re: teflontom

              You are basically correct, although it's a question of cooking temperature, not cooking time or whether or not you use smoke. Cure #2 is for uncooked, dried sausages such as salami and sausages that are cold smoked and then dry aged. The nitrate is gradually converted to nitrite as the sausage ages.

              1. re: teflontom

                For a nice review of curing chemistry, see (the site asks for a password but if you just click Cancel it lets you download the file anyway).

                The sequence of reactions during curing is Nitrate --> Nitrite --> Nitrous acid --> Nitric oxide and the Nitric oxide reacts with myoglobin to generate the pink color.