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Author: Subject: commercial grade sodium nirrate for curing meat
Mixell
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[*] posted on 20-6-2013 at 08:55
commercial grade sodium nirrate for curing meat


Hello,
I want to make some home made bacon, but I'm in short supply of curing salt/prague powder. I do have some sodium nirate, which in turn can be turned into sodium nitrite, the problem is that it is commercial grade, not food grade.

Any ideas on what contaminants it can contain? I'm especially worried about things like heavy metals. The occasion potassium or chloride ion should pose no problem...
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Bot0nist
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[*] posted on 20-6-2013 at 10:25


Some info found at www.nakka-rocketry.net/knpurify.html

More geared for pyro, but it claims common impurities are clay, sand, KOH and NaOH, potassium carbonate, and ammonium nitrate. He recomends PH checks and multiply recrystalizations. Sorry, I couldnt find anything about consumpion related impurities.

Good luck, and let us know how the reduction to nitrite works out.




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Mixell
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[*] posted on 20-6-2013 at 11:13


I'm inclined to degrade it by heat, and ideas on that?
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violet sin
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[*] posted on 20-6-2013 at 12:21


I'll look for the reference later, but I thought the only reason they started using the nitrite/nitrate salts was it improved color of the meat after curing. ie. a lill more pink and savory looking. if you aren't planning on selling the cured product, ya might wanna use something else.

wiki-
"In the European Union it may be used only as a mixture with salt containing at most 0.6% sodium nitrite."

http://meatsci.osu.edu/borca2.htm
"The current routine use of ascorbates (ascorbic acid, sodium ascorbate, erythorbic acid and sodium erythorbate) by the meat processing industry is important not only because it accelerates and improves the curing process but also the use of ascorbates inhibits nitrosation reactions which might result in formation of carcinogenic nitrosamines (Mirvish et al, 1995)."

"One possible chemical hazard involved in producing processed meats would be an error in the use of sodium nitrite.� If too much is added there is a risk of illness, even death, to the consumer."


prob not the best citing available, but a quick search. I will still look for the other respectable paper I had saved this evening.

[Edited on 20-6-2013 by violet sin]
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[*] posted on 20-6-2013 at 12:37


Nitrite is added to food, even today, to inhibit the toxin production of Clostridium botulinum, the reaction with hemoglogin to form nitricoxide­ myoglobin was just an added bonus in the old days, today nitrite and nitrate is added for both reasons.

Homemade bacon will do just fine with seasalt and smoking, more than enough to kill off most germs.

IIRC Clostridium botulinum only produces it's toxin if it is growing anaerobic, e.g. canned etc. and not if it is left in open air, but don't quote me on that...




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[*] posted on 20-6-2013 at 12:40


Making sodium nitrite from the nitrate is not trivial. It is not a matter of simply heating the nitrate. You need very strong heating and in practice this does not work for making pure nitrite. You need a suitable reductor to reduce sodium nitrate to the nitrite and then you need to purify the product. There is a thread on making nitrites from nitrates on sciencemadness. Another option is simply buying it. It is quite cheap and available on eBay. I think that sodium nitrite is one of those chemicals, not worth making yourself. if you want curing salt, then you can even buy it pre-mixed, NaCl with 0.6% NaNO2 mixed in. Also available on eBay.



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[*] posted on 20-6-2013 at 12:59


Prague Powder aka Pink Salt, which is a mix of salt and sodium nitrite and nitrate is widely available on eBay, Amazon and elsewhere.
The specifications are here;
http://en.wikipedia.org/wiki/Prague_powder
Buy the commercial product and use it in accordance with the instuctions.
If you know someone that is experienced in curing meat then get their advice and help. Do a few runs with them.
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Mixell
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[*] posted on 20-6-2013 at 13:05


It is indeed not worth making those type of chemicals at home, but getting it from an over-seas supplier will take me one to two weeks, and I want to make that bacon now =)

I needed only a small amount (~0.5g), so I just took a small amount of nitrate and heated it with a small torch, until no bubbling was visible. Left over nitrate should not pose a problem, as it is often used together with nitrite in curing mixtures.

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[*] posted on 20-6-2013 at 15:54


Did you test to confirm the nitrite? I wonder what ratio to nitrate was obtianed.






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[*] posted on 20-6-2013 at 19:31


I did not, the decomposition takes quite some time, nerves, and effort, not to mention the analysis that needs to be done on that sample.

I've currently put my chemistry hobby on a halt, as I'm going on a long vacation in a couple of weeks, followed by my first year at the university.

I might resume it when I'll get a proper access to the university labs (and hopefully incorporate it somehow into my studies).

I'm not familiar with any simple quantitative test for nitrate/nitrite in a solution containing both, as acid will decompose the nitrite. May be some colorimetric analysis can be helpful here (with nitrite acting as a ligand)?
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[*] posted on 20-6-2013 at 19:42


Add concentrated HCl(aq) to solid and observe brown gas evolution, IIRC.



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[*] posted on 21-6-2013 at 06:06


That will indeed detect the presence of nitrite, but it is not a qualitative analysis (at least not an accurate and simple one).
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[*] posted on 21-6-2013 at 07:30


That is true, it will only confirm the presence of the nitrite. I can not think of a trivial way to separate or determine the amounts of nitrate to nitrite.



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[*] posted on 22-6-2013 at 18:37


Quote: Originally posted by Bot0nist  
That is true, it will only confirm the presence of the nitrite. I can not think of a trivial way to separate or determine the amounts of nitrate to nitrite.


Maybe adding acid like sulfuric or some solid acid then heating and measuring the volume of generated gas?
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[*] posted on 22-6-2013 at 19:15


The problem is that some NO2 can escape and mix with the NO. Oxygen can also interfere and oxidize the NO to NO2...

Anyway, it won't be too easy or accurate in an amateur set-up.
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[*] posted on 22-6-2013 at 19:39


Quote: Originally posted by Mixell  
The problem is that some NO2 can escape and mix with the NO. Oxygen can also interfere and oxidize the NO to NO2...

Anyway, it won't be too easy or accurate in an amateur set-up.


That is true.. I guess we can always estaminate and use excess if it doesn't interfere. Other than that I don't know a good solution to it.
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[*] posted on 20-11-2015 at 13:03


Hi,
colorimetric quantitative test for nitrite & nitrate anions is widely available, cheap and pretty accurate.
You'll find the test solutions in nearly every pet shop selling fish.
The only downside is that you will have make fairly dilute solution.
If dilution is done properly error margin can be very small.

Never researched the process.
When I get home I'll look it up in literature.
That is if I remember - have excellent memory, but unfortunately very short :D

Regards
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