Resource Stability of SN and N

[Endisclose]

I ordered SN recently but I don't plan to use it now (stupid decision, I know). It'll be in a plastic bottle thingy. If I unseal it for testing will I be able to use it in june 2026?

I am not sure that's a good idea. SN oxidises in an accelerated manner when exposed to air. The vaccum seal on the bottle keeps the air and moisture out and it can stay fresh and potent for a long time if stored properly in a dry, non humid environment.

Breaking the seal would let air and moisture ingress into the bottle converting the SN to sodium nitrate rendering it unsuitable for said purpose. I think it's generally a good idea to test just before CTB at least that's what I am planning to do.

Or test on an extra spare that one may have ordered. Once the seal is broken it might be good enough for just 3 months and probably not advisable to be relied on after that period.

 

[Endisclose]

My SN is 5 years old in its original unopened airtight box. Is it still good you reckon?

I think it should be, as per the research I've done. Could you test it and let us know the results on this thread when you open it? It would be very useful to a lot of people on this forum am sure.

I am keenly interested as my SN would be about 4 years old by the time I am planning to use it. Mine is in a hdpe container with a factory made vacuum seal. I've placed it in an airtight lock n lock container for further protection. If yours is similar, there is a high chance it could still be good.

The expiry date on my SN is 5 years from the date of manufacture. That means the contents are guaranteed to be within assay specifications (mine is 98.4% pure) within that period by the manufacturer. That doesn't mean that the assay will drop overnight beyond that period.

As per my research if stored well, SN could last twice the shelf life, or maybe even much longer than that - possibly even 15 to 20 years if stored properly of course..as mentioned in the discussion in the link below.

Sciencemadness Discussion Board - Nitrite shelf life - Powered by XMB 1.9.11

 

[Hiro Uchiha]

I think it should be, as per the research I've done. Could you test it and let us know the results on this thread when you open it? It would be very useful to a lot of people on this forum am sure.

I am keenly interested as my SN would be about 4 years old by the time I am planning to use it. Mine is in a hdpe container with a factory made vacuum seal. I've placed it in an airtight lock n lock container for further protection. If yours is similar, there is a high chance it could still be good.

The expiry date on my SN is 5 years from the date of manufacture. That means the contents are guaranteed to be within assay specifications (mine is 98.4% pure) within that period by the manufacturer. That doesn't mean that the assay will drop overnight beyond that period.

As per my research if stored well, SN could last twice the shelf life, or maybe even much longer than that - possibly even 15 to 20 years if stored properly of course.

Sciencemadness Discussion Board - Nitrite shelf life - Powered by XMB 1.9.11

Correct. Proper containment is the determining factor. Deterioration of sn is usually associated with prolonged exposure to vapor+warmer temp. If it's within airtight container, the salt will remain it's purity and viability for years.

 

[Steve Vermont]

I just received SN in a sealed plastic bag. It's not even vacuum sealed: there's air in it.

I am thinking of taking it out, putting it into gel capsules, then tossing those into a plastic vaccum-sealable bag with some gel dessicant packets and then sealing that. Do you think this will work to keep it storeable, long term?

 

[Hiro Uchiha]

I just received SN in a sealed plastic bag. It's not even vacuum sealed: there's air in it.

I am thinking of taking it out, putting it into gel capsules, then tossing those into a plastic vaccum-sealable bag with some gel dessicant packets and then sealing that. Do you think this will work to keep it storeable, long term?

I think it could work especially if your salt is very dry beforehand. However, I'm not exactly sure about the gel capsules. Depending on what kind, they can degrade rather faster than the SN you put in them.

 

[Steve Vermont]

Perhaps. However, since it's all going to be vaccum-sealed, at least the SN should remain potent, right?

 

[Hiro Uchiha]

Perhaps. However, since it's all going to be vaccum-sealed, at least the SN should remain potent, right?

Yes, in theory, that set up should keep your SN viable for a long time.

 

[Steve Vermont]

I was planning on doing this with my OLD SN, but given that this stuff came in a bag with air inside it. Take a look at these and see what y'all think is the most secure. To me, it's the one on the left. It's two years old. The black one is about four years old. The new stuff is on the right. It came in a sealed thick plastic bag and I triple-bagged it to be safe.

It's the stuff on the right that I think it's best to put in capsules and vacuum-store.

(Shit, I have enough SN here to kill an elephant. It's cheap and I think that soon they're going to make it unavailable to casual buyers, so I keep buying a new supply every other year or so.)

 

[Hiro Uchiha]

I was planning on doing this with my OLD SN, but given that this stuff came in a bag with air inside it. Take a look at these and see what y'all think is the most secure. To me, it's the one on the left. It's two years old. The black one is about four years old. The new stuff is on the right. It came in a sealed thick plastic bag and I triple-bagged it to be safe.

It's the stuff on the right that I think it's best to put in capsules and vacuum-store.

(Shit, I have enough SN here to kill an elephant. It's cheap and I think that soon they're going to make it unavailable to casual buyers, so I keep buying a new supply every other year or so.)

View attachment 182452

You got enough sodium nitrite to cure beef from around 75 cattles
Yes, I'd trust the bottled SN more compared to the one that came in a plastic bag in terms of security. Better use the bagged SN for capsule storage (if you really want to).

 

[Steve Vermont]

You got enough sodium nitrite to cure beef from around 75 cattles
Yes, I'd trust the bottled SN more compared to the one that came in a plastic bag in terms of security. Better use the bagged SN for capsule storage (if you really want to).

Well, what else am I going to do with it? :D

I think it might help ease me a little. Like cutting. Taking steps which won't be fatal but which COULD be, maybe.

 

[wishingonstars]

If I received SN in a doypack that had a bit of air in it would it be better for storage to leave sealed or to open press the air out and close it back up with the resealable zipper thing?

 

[Steve Vermont]

I dunno. I mean, I repacked mine and vaccum-sealed the result twice. But I have no idea how much exposure to air might have affected it.

 

[CPY]

The only SN source in my country sells it in a non-sealed plastic envelope.Last time I checked it was almost hardened whilst when I first bought it was mostly soft, is it still reliable? Should I buy another one and put it in some kind of container what type of container do you recommend to keep it reliable for at least 5 years?

 

[Macedonian1987]

My SN came in a similar bottle like the one shown on the photo (The 100g one). On the bottle it has a retest date: June 2029. As a precaution I put it in 2 vacuum sealed plastic bags and I put it in a dark place. When I shake it, it feels like most of the SN is clumped into a one big chunk. I hope this is normal, and that my SN hasn't gone bad. I never opened the bottle. It's still sealed.

 

[Steve Vermont]

My sealed SN is similar. After taking the stuff out of the baggie and messing around with it, it seems to me that it would clump easily, even without moisture. It's got a kind of… hard to describe it… greasy texture to it? Not actually greasy, but moist-looking without being moist, if you catch my drift. It seems that it would clump easily.

I repackaged my bagged SN into loose SN in vaccuum sealed packs and gel capsules, likewise in vaccuum sealed packs. So we'll see what happens to it, long term.

I can already say that repackaging it in gel capsules is a no starter: the SN has gone distinctly yellow. At first I thought it might be due to leakage, but then I realized that gel capsules have a large water content and SN is very hydrophilic. My hypothesis is that the SN sucked the moisture out of the gel capsules and thus became contaminated. I will wait to around Christmans to unpack them and see what happened. If my hypothesis is correct, the capsules should be dry and incredibly brittle by that time.

I'll post the results here.

In the meantime, if you're going to encapsulate your SN for easier ingestion, do it right before taking it. Even two weeks after I encapsulated mine, the SN has become visibly contaminated.

 

[IwantHappiness]

Hi,
I need some help with a question about the long-term stability of sodium nitrite.

In April 2025 I purchased SN online. The product was manufactured by a reputable company that produces many other chemical powders, so I consider the source highly reliable and the quality of the SN good. The SN arrived in an opaque white plastic container with a tamper-evident safety seal — the kind that shows clearly whether someone has opened the container before.

Because the manufacturer is serious and well-known, I assumed that keeping the SN in its original container would be an adequate storing method. I also assumed that the safety seal implied the container was airtight. Now I'm starting to question that assumption.

In the thread I will attach a photo of the container, so you can see exactly what type of packaging my SN is stored in.

I have noticed that several users here store their sodium nitrite containers inside additional zip-lock plastic bags, or even place the whole container inside a larger airtight box. I never did this, because I always thought: what would be the point? If the manufacturer sells SN in this container, it should logically be suitable for preventing degradation into nitrate. Otherwise, the company would lose credibility, and customers would complain.

But now I'm starting to doubt. Why should I put plastic bags around the SN container, or place it inside an airtight container? This product was sold by a serious chemical supplier — not by someone inexperienced. Why would they choose packaging that cannot prevent the SN from degrading into nitrate? The container itself even states that the product has a 3-year shelf life from the production date.

I'd really appreciate your insights on this. I need to understand whether my storage method is sufficient or if I should improve it.

Thanks in advance

 

[Endisclose]

Hi,
I need some help with a question about the long-term stability of sodium nitrite.

In April 2025 I purchased SN online. The product was manufactured by a reputable company that produces many other chemical powders, so I consider the source highly reliable and the quality of the SN good. The SN arrived in an opaque white plastic container with a tamper-evident safety seal — the kind that shows clearly whether someone has opened the container before.

Because the manufacturer is serious and well-known, I assumed that keeping the SN in its original container would be an adequate storing method. I also assumed that the safety seal implied the container was airtight. Now I'm starting to question that assumption.

In the thread I will attach a photo of the container, so you can see exactly what type of packaging my SN is stored in.

I have noticed that several users here store their sodium nitrite containers inside additional zip-lock plastic bags, or even place the whole container inside a larger airtight box. I never did this, because I always thought: what would be the point? If the manufacturer sells SN in this container, it should logically be suitable for preventing degradation into nitrate. Otherwise, the company would lose credibility, and customers would complain.

But now I'm starting to doubt. Why should I put plastic bags around the SN container, or place it inside an airtight container? This product was sold by a serious chemical supplier — not by someone inexperienced. Why would they choose packaging that cannot prevent the SN from degrading into nitrate? The container itself even states that the product has a 3-year shelf life from the production date.

I'd really appreciate your insights on this. I need to understand whether my storage method is sufficient or if I should improve it.

Thanks in advance

View attachment 186934

The images shared here seems like it's a vaccum sealed container with a plastic seal. If that is the case, then the packaging is good enough as it is and doesn't need any extra containers. Most people just go the extra mile from being extra cautious. Like putting it in an airtight container with silica gel packets can give people a greater sense of security, but its not really required if the packaging is vaccum sealed and has an unbroken plastic seal.

I presume there will be a further induction heat sealed aluminium foil inside which should help keep the contents fresh for a long time. The vaccum sealing keeps the moisture and air out from getting in. This would be the best protection for the contents inside.

The only case where I'll worry is if it's not a vaccum sealed container and maybe has a screw type lid - those sorts of boxes are less efficient in keeping the moisture out. I have one like that and the contents inside seem to have clumped up into one solid block although I haven't opened the box at all.

Also just because the contents have clumped up doesn't mean it's turned to nitrate. It probably means the SN doesn't have adequate amounts of caking agent and is actually purer, but because of the clumping, that's an indication that some moisture has got in either before it was packed or afterwards and hence the shelf life will be limited.

The pack of SN with the screw type lid I have has supposedly a shelf life of 4 years until which time I think it will do the job at the recommended amount but will still have to be tested. I also have another hdpe pack with the factory made vaccum seal that claims to have a shelf life of 5 years. The image shared being somewhat similar to what I have, I would have expected the shelf life to be 5 years and hence I am a little surprised that it's just 3 years. Honestly I dunno why manufacturers put these sorts of numbers here as SN is a very stable compound and from the research I've made, if it's stored properly, it should easily be good enough for at least double the claimed shelf life.

I think the reason why they put that sort of number is because that's the time frame they feel they can guarantee the contents to be at the assay level mentioned in the packaging. So if a packaging can hold the contents at an assay level of 98% or 99% for 3 to 5 years, one can imagine how much longer it can hold it until the assay level reaches 95% which is the generally recommended assay level. IMO at the recommended amount of SN mentioned in the PPeH, even an assay level of 90% should be adequate. Hence one can see that if the packaging is solid, there's no reason why the contents inside shouldn't be good enough for a long time.

 

[IwantHappiness]

The images shared here seems like it's a vaccum sealed container with a plastic seal. If that is the case, then the packaging is good enough as it is and doesn't need any extra containers. Most people just go the extra mile from being extra cautious. Like putting it in an airtight container with silica gel packets can give people a greater sense of security, but its not really required if the packaging is vaccum sealed and has an unbroken plastic seal.

I presume there will be a further induction heat sealed aluminium foil inside which should help keep the contents fresh for a long time. The vaccum sealing keeps the moisture and air out from getting in. This would be the best protection for the contents inside.

The only case where I'll worry is if it's not a vaccum sealed container and maybe has a screw type lid - those sorts of boxes are less efficient in keeping the moisture out. I have one like that and the contents inside seem to have clumped up into one solid block although I haven't opened the box at all.

Also just because the contents have clumped up doesn't mean it's turned to nitrate. It probably means the SN doesn't have adequate amounts of caking agent and is actually purer, but because of the clumping, that's an indication that some moisture has got in either before it was packed or afterwards and hence the shelf life will be limited.

The pack of SN with the screw type lid I have has supposedly a shelf life of 4 years until which time I think it will do the job at the recommended amount but will still have to be tested. I also have another hdpe pack with the factory made vaccum seal that claims to have a shelf life of 5 years. The image shared being somewhat similar to what I have, I would have expected the shelf life to be 5 years and hence I am a little surprised that it's just 3 years. Honestly I dunno why manufacturers put these sorts of numbers here as SN is a very stable compound and from the research I've made, if it's stored properly, it should easily be good enough for at least double the claimed shelf life.

I think the reason why they put that sort of number is because that's the time frame they feel they can guarantee the contents to be at the assay level mentioned in the packaging. So if a packaging can hold the contents at an assay level of 98% or 99% for 3 to 5 years, one can imagine how much longer it can hold it until the assay level reaches 95% which is the generally recommended assay level. IMO at the recommended amount of SN mentioned in the PPeH, even an assay level of 90% should be adequate. Hence one can see that if the packaging is solid, there's no reason why the contents inside shouldn't be good enough for a long time.

Hi, Thank you very much for your detailed reply, I really appreciate it.

I just want to clarify my situation: I did not buy the SN directly from the manufacturer, but through a seller. I am not sure if the seller handled the container carefully, and I also don't know if there were any possible damages during handling or shipping, so I am a bit concerned.

Despite the cap not being fully screwed on, my SN container has never been opened, and the seal is intact. I stored it in a cool, dark place, and it is almost certainly not airtight because it very likely does not have a foil seal.

The manufacturer guarantees a shelf life of three years, but this would apply if the manufacturer had given it directly into my hands… unfortunately there is a seller in between.

Given the possibility of micro-damages during handling or shipping, if the seller handled the container roughly(it is not airtight probably) or if there were any issues during shipping, which could have created microcracks, do you have any idea how much the purity could have decreased in about ten months (the SN was produced ten months ago)?

Thank u in advance.

 

[Endisclose]

Despite the cap not being fully screwed on, my SN container has never been opened, and the seal is intact.

This is confusing. You're saying the cap is not fully screwed on, and then you're saying the seal is intact. I find those two statements to be contradictory to each other.

I just want to clarify my situation: I did not buy the SN directly from the manufacturer, but through a seller. I am not sure if the seller handled the container carefully, and I also don't know if there were any possible damages during handling or shipping, so I am a bit concerned.

I think this is your SI/anxiety at work here. You are not sure if it was handled correctly, you don't know if there were possible damages. By the same token you are not sure if it wasn't handled correctly and you don't know if there are no damages..I think it's often a good dictum to act based on factual evidence and what you know..for sure rather than what might be ( which could be a million things).

Given the possibility of micro-damages during handling or shipping, if the seller handled the container roughly(it is not airtight probably) or if there were any issues during shipping, which could have created microcracks, do you have any idea how much the purity could have decreased in about ten months (the SN was produced ten months ago)?

Look at the container closely, do you see any micro cracks or micro damages? If you can't see anything, I think it should be ok. I don't think there is any danger of there being a crack that can be observed only via a microscope and not with the naked eye. The tragedy and the irony is that the box might well be and most probably is intact and well, but if it opened in order so that the contents may be "checked", it will last probably only 3 months from the time of opening.

The manufacturer guarantees a shelf life of three years, but this would apply if the manufacturer had given it directly into my hands… unfortunately there is a seller in between.

Btw..what makes you think the guarantee of 3 years would stand if the manufacturer had given it directly into your hands. What prevents the possibility of the box developing microcracks or micro damages on the factory line? Maybe it received a couple of blows here and there or fell once but was put back into place. I'd humbly submit that these sound more like imaginary fears and that there's nothing worse to play havoc with your anxiety. My suggestion would be to look at the seal closely. If it's intact and if you don't see any cracks, I think it should be good.

Also if the box is tilted up and down, one should feel the easy flow of the contents inside. On the other hand if it's turned into one solid block or sounds lumpy, that would suggest the presence of moisture inside (which by itself need not be all bad, but only concerning). If that were the case, I don't think it would be advisable to count on it beyond the advertised shelf life period..If it's still free flowing, then IMO the contents inside should still be good enough.

 

[dalemar]

My SN came 1 month ago in a vaccum sealed bag (1kg). It was 100% powder, no clumps.
I opened it, barely, on a corner at the top, and removed 50g, and put those 25/25 in 2 plastic bottles and closed them as well.
I removed as much air as possible from the plastic bag with the remaining 950g, and put that bag in airtight container, with the 2 bottles.
I plan to CTB in 25 days, so the SN would be 2 month old.
Manufactured date was marked as 1 year ago, and expiration date in 2 years from now.
Do you think the 25g in the 2 bottles will be good enough to prepare the drinks? Or should I refill them with new SN from the 950g bag? Everything is stored at a dry place, with good temp and no light. The SN in the 950g bag still quite powdery, only minor clumps have formed. I just checked it twice.

 

[GHome]

On the other hand if it's turned into one solid block or sounds lumpy, that would suggest the presence of moisture inside (which by itself need not be all bad, but only concerning).

I bought SN from Ukraine in May this year. It came packaged in black plastic, I haven't opened it, but it's hard, very hard, so the question is, can it still be used? Can anyone send me a PM with where I can buy SN again? Or a link to a thread on the forum that contains hints about where it can be bought? Also, can I freeze my SN to increase its shelf life?

 

[Endisclose]

I bought SN from Ukraine in May this year. It came packaged in black plastic, I haven't opened it, but it's hard, very hard, so the question is, can it still be used?

If it's hard, it's integrity is questionable. The only way one can know is to test it I guess.

Also, can I freeze my SN to increase its shelf life?

No. This will accelerate the conversion to nitrate IMO. SN is hygroscopic, meaning it absorbs moisture, and when it does, it gets converted to sodium nitrate.

 

[diagon24]

What's the general consensus on opening an airtight container of 500g of SN to test and then putting the lid back on and storing in an air tight container? Surely 3 months from opening seems very quick for it to degrade?

 

[dalemar]

My SN came 1 month ago in a vaccum sealed bag (1kg). It was 100% powder, no clumps.
I opened it, barely, on a corner at the top, and removed 50g, and put those 25/25 in 2 plastic bottles and closed them as well.
I removed as much air as possible from the plastic bag with the remaining 950g, and put that bag in airtight container, with the 2 bottles.
I plan to CTB in 25 days, so the SN would be 2 month old.
Manufactured date was marked as 1 year ago, and expiration date in 2 years from now.
Do you think the 25g in the 2 bottles will be good enough to prepare the drinks? Or should I refill them with new SN from the 950g bag? Everything is stored at a dry place, with good temp and no light. The SN in the 950g bag still quite powdery, only minor clumps have formed. I just checked it twice.

Replying to myself.
As an insurance, I bought another kg of SN. Will leave it in the sealed bag. I will probably CTB soon, using the SN from the first order, but just In case, I have 2 kg now, one being fully sealed.

What's the general consensus on opening an airtight container of 500g of SN to test and then putting the lid back on and storing in an air tight container? Surely 3 months from opening seems very quick for it to degrade?

If I had to bet, I would say 3 month is well ok if properly stored.

 

[letmeseethedeath]

I'd like to preface this to hopefully help people not make rash decisions due to the fear that their suicide method will go "bad" and they feel forced to take it before they truly want to. Freedom of choice means everything.

There is a lot of misconception on here about how long both of these chemicals last before they are no longer useable. both SN and N are highly stable compounds in general when stored in a cool, dry, dark environment and unopened the change in potency will diminish very slowly over time. Even when stored in "unstable" conditions, they both will last for a very long time and the loss of potency is negligible. Almost all chemicals are good past their expiration date, an expiration date is not what you may think, " Since a law was passed in 1979, drug manufacturers are required to stamp an expiration date on their products. This is the date at which the manufacturer can still guarantee the full potency and safety of the drug." [1] most drugs will last for decades past expiration, some even for centuries. In the US expired drugs are sold to the military at a discounted price since legally they are no longer acceptable to be sold to the general public.

Stability of Sodium Nitrite

First we will look at SN since it is far more commonly used. "Curing salt has no hard expiration date. If your curing salt is only salt and sodium nitrate or sodium nitrite, it's good forever. Salt itself never goes bad, though yellowing and other discoloration is common. Moisture is a potential problem as it attracts microbes. To prevent such threats, store curing salts in dry, moisture-lock, airtight containers and in a cool dry place, such as your pantry or a dry goods storage closet. Do not refrigerate or freeze curing salt." [2]

Some people are worried that clumping lowers it's efficacy, this is not the case. Here is a picture of pure sodium nitrite [3] and as you can see there is clumping. Small compounds will slowly stick together over time, it is natural and usually has nothing to do with it's efficacy.

View attachment 128403

Another article showing that is it highly stable
click here

This is a picture of an aquarium test strip that was used on SN that has been sitting in a bottle of tap water with a cap on for almost a year. previously it was believed you needed to use distilled water to insure sodium nitrite would breakdown into sodium nitrate at a much slower rate. considering this SN is still useable in very subpar conditions shows this is not the case as well as shows how stable it is as a compound.

View attachment 128405

This shows Sodium Nitrite is much more stable than previously thought, even in unpleasant environments.

Stability of Nembutal (pentobarbital)

Onto Nembutal, although it isn't talked about much anymore I still think it would be a good idea to show some information regarding it. In the past there was a lot of fear that it would go bad past the due date, as well as once it was opened you had to drink it in a certain amount of time. I would like to showcase why this is wrong.

I believe these two articles are the most notable and shows N in both it's stable and unstable environment and how it reacts.

Article 1: https://pubmed.ncbi.nlm.nih.gov/26234474/

The biggest takeaway from this is, "We determined that the drug degraded at a maximum of 0.5% per year in our preparation (alkaline water/propylene glycol/ethanol) when stored in the dark at room temperature. "

Article 2: https://pubmed.ncbi.nlm.nih.gov/23982045/

The biggest takeaway from this is, "the pentobarbital sodium in injection appears to be very stable, because the loss in potency was only about 6.2% after it was boiled in water for 1.5 hours."

This isn't really related but I thought I'd share this as well. There is an anecdotal report on Erowid about a person who took N recreationally for an extended period of time. The biggest thing to note is they found expired vet N had a worse taste. "some of the bottles were past a use-by date they seemed to be the most foul to drink and provided an inferior experience". An inferior experience in this context refers to the high and possibly that the potency of N was only slightly diminished.

Pentobarbital - Erowid Exp - 'Nice but Zombie Effects Long Term'

An Experience with Pentobarbital. 'Nice but Zombie Effects Long Term' by Whynot

www.erowid.org

As you can see N is also a highly stable compound and will last long past it's shelf life with very little loss in potency. When the liquid turns cloudy it means nothing in terms of efficacy loss and is just an arbitrary rule in determining it is no longer good for sterile use in a medical setting.


I hope this thread has helped to clear up the air that Sodium Nitrite and Nembutal do not go bad quickly. You do not have to make a rushed decision to ctb because of the fear that either compound will not work. both substances are highly lethal decades past expiration. Exercise caution and make sure ctb is the right choice for you.





[1] https://www.health.harvard.edu/staying-healthy/drug-expiration-dates-do-they-mean-anything
[2] https://www.leaf.tv/articles/does-curing-salt-expire/
[3] https://en.wikipedia.org/wiki/Sodium_nitrite

thank you so much i'm seriously considering giving a shot to sodium nitrite i don't have a family anymore i don't have anything
i just wanna die alone as i came to this world and never be found

 

[U. A.]

I know @bed is hardly online these days and likely doesn't watch this thread (hence the tag, just in case), but after initially being calmed by this thread re: my vintage SN, I've noticed some significant issues. Would appreciate a response when possible, from OP or anyone knowledgeable:

Almost all chemicals are good past their expiration date, an expiration date is not what you may think, "Since a law was passed in 1979..."

The quote that follows and the citation for it refer strictly to medication, which SN isn't. It's a chemical. I don't know what the regulations are on chemicals, but in any event, this source only applies to legitimate-market pharmaceuticals, and only in the USA. Additionally, the conditions of whatever "lab" our questionable SN came from can't be verified to be at the level of commercial ones.

First we will look at SN since it is far more commonly used. "Curing salt has no hard expiration date. If your curing salt is only salt and sodium nitrate or sodium nitrite, it's good forever.

Again, apples and oranges—notice it says "If your curing salt is only salt and sodium nitrate or sodium nitrite". Not only do we know curing salt ≠ sodium nitrite, but this source is presumably about the expiration for the purposes of curing meat. In any event, curing salt is around 90% sodium chloride.

Another article showing that is it highly stable

Where? The link that follows is to a topic page on SciendeDirect, not an article. There are many previews of many articles listed on that page.

This is a picture of an aquarium test strip that was used on SN that has been sitting in a bottle of tap water with a cap on for almost a year.

What's the source on this? There is none whatsoever, not even a link to a post here or OP saying it was their own information. And to make matters worse there are five chemical indicator colors on that test strip. With no reference gradients, or even confirmation of which chemicals they even are.

 

[Obliviate]

Replying to myself.
As an insurance, I bought another kg of SN. Will leave it in the sealed bag. I will probably CTB soon, using the SN from the first order, but just In case, I have 2 kg now, one being fully sealed.

If I had to bet, I would say 3 month is well ok if properly stored.

Hey, I'm in the same boat as you. I have old SN can you please DM me for the other source you purchased it at.