Warning Regarding Mylar Bag Storage

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beezer

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Jul 12, 2013
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Greetings Folks,

I wanted to pass along a horror story I experienced last week dealing with the long term storage of sealed tins in mylar bags.

Years ago I made what I thought was the brilliant move of sealing tins in mylar bags. Anything that I was either intentionally aging or knew I wouldn't get to for 5-10 years got sealed up for safe keeping. Well last week on a whim I opened up a mylar bag that held a pair of tins of Samuel Gawith (S.G.) FVF that I purchased back in 2013 and they had a good amount of rust on them. Panicked I opened up the rest of my FVF stash and encountered the same: rust around the edges of the lid and specks of rust on the sides and bottoms. Thinking maybe it was a S.G. thing I opened up all my St. James Perique, Squadron Leader w/ Perique, and any other S.G. blends that were sealed and same story...rust! Some tins had a lot of it...some tins just a little.

At this point I opened every mylar bag that held a tin in my cellar. At least 600 tins across all blends, all brands, and all sealed in mylar bags for the last ~5 years or so...here's what I discovered:

  • Samuel Gawith tins were the worst. Out of 40x tins across various blends 90% had rust ranging from moderate to severe.
  • Balkan Sobranie tins were a close second. Out of 20x tins about 75% had rusted as bad as the S.G.
  • MacBaren HH Mature Virginia (a dozen 3.5 oz tins) and HH Latakia Flake (same volume) got hit hard. I wonder if the vinegar in the blends contributed.
  • MacBaren Navy Flake - 3x 3.5 oz tins popped their lids, but no rust.
  • Esoterica tins of Dorchester and Dunbar were all hit with specks of rust all over.
  • Dan Limerick Virginia Flake had rusting along the rim of the lids.
  • A few other blends had the beginnings of rust spotting on them, but weren't overly concerning.

Thankfully I found some widemouth jars at Target and bought them up to transfer the tobacco into jars. In every case the seal on the tins were fine and the tobacco in great condition, but rust is rust and I don't want any pinholes down the road.

At any rate...I know there are other mylar maniacs on the board like me, so take this as a bit of a warning. Out of at least 600 tins I'd say rust was present on 12-15% of them. By comparison, naked tins of the same blends with the same age that were in sealed storage containers were in perfect shape as if I purchased them yesterday.
 

cosmicfolklore

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Aug 9, 2013
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Helena, Alabama
Yet, I have most of those blends still in the tins in my cellar without being in bags, and no rust, no loss of seal, all doing just fine.

This is all a great heads up. My spider senses tell me that some are going to tell you to open all of the tins and put them in jars. Some are going to say that they have tins in bags with no problems. Some are going to say that all of this is just being paranoid, and no one will be right, and no one will be wrong. puffy
 

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BarrelProof

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beezer

Preferred Member
Jul 12, 2013
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An excess humidity? It looks like his tobacco is in a cave. Do you live in a very cold area?

I live in Central Virginia where we experience all four seasons and my cellar is kept in a temperature/humidity controlled environment.

One theory I had on the tins in the mylar bags was that the moisture that escaped from the tins (since all tins do leak at varying rates) had nowhere to go and created excess humidity inside the bag that led to the rusting. The S.G. blends come moist and the rectangle tins are notorious leakers....I might be wrong, but it's a theory.

The MacBaren blends contain some vinegar I believe and I wonder if much like the older ODF square tins the component caused the corrosion while inside the bag without room to breathe, etc. Another theory I may be wrong on...but tossing it out there.

Toss one of these in with every bag and make sure to vacuum seal, not just seal. No oxygen = no rust.

This may have been my fatal short cut. I didn't vacuum seal any of the bags...everything was done by hand. And the oxygen absorbers were repurposed for my storage containers full of tins when in hindsight I should have inserted them in the mylar with the tins.
 

BROBS

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Nov 13, 2019
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I live in Central Virginia where we experience all four seasons and my cellar is kept in a temperature/humidity controlled environment.

One theory I had on the tins in the mylar bags was that the moisture that escaped from the tins (since all tins do leak at varying rates) had nowhere to go and created excess humidity inside the bag that led to the rusting. The S.G. blends come particularly moist and the rectangle tins are notorious leakers....I might be wrong, but it's a theory.

The MacBaren blends contain some vinegar I believe and I wonder if much like the older ODF square tins the component caused the corrosion while inside the bag without room to breathe, etc. Another theory I may be wrong on...but tossing it out there.



This may have been my fatal short cut. I didn't vacuum seal any of the bags...everything was done by hand. And the oxygen absorbers were repurposed for my storage containers full of tins when in hindsight I should have inserted them in the mylar with the tins.
Absolutely the problem is moisture coming out of the tin. They “breathe”

So a desiccant would most likely dry out your tins IMo
 

cosmicfolklore

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Aug 9, 2013
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Toss one of these in with every bag and make sure to vacuum seal, not just seal. No oxygen = no rust.

I read up on those oxygen absorbers. They work by the iron dust corroding quickly, using up about half as much oxygen as the filling shavings in mass. Since there's only a pinch of that iron dust in there, they only absorb a tiny bit. And, do you want to add something that accelerates rust as a means of only removing a tiny bit of oxygen. It sounds like you may be enhancing the rust problem... and in the very least not solving much of the oxygen problem in the first place. Just a thought.
 

BarrelProof

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I read up on those oxygen absorbers. They work by the iron dust corroding quickly, using up about half as much oxygen as the filling shavings in mass. Since there's only a pinch of that iron dust in there, they only absorb a tiny bit. And, do you want to add something that accelerates rust as a means of only removing a tiny bit of oxygen. It sounds like you may be enhancing the rust problem... and in the very least not solving much of the oxygen problem in the first place. Just a thought.

I’ve used Mylar bags big enough for more than one desiccant package.

I think, as I mentioned, when used with a quality vacuum packer, they’re an added, unnecessary level of protection. If you create an environment inside the bag where the majority of the oxygen has already been removed, I can’t see how they wouldn’t be at least viable.

I can crack a mylar bag and see...
 

BarrelProof

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This is the conclusion I've reached. The only thing that will get the mylar treatment from this point forward are the boxes of MacBaren that I occasionally stock up on.

When vacuum sealed, it’s also viable for bulk. I know jars reign supreme, but I still use mylar for blends of which I have entire shelves worth of jars. I can stuff them as tightly as possible into jars, but I can’t compete with the chamber vacuum. That thing turns bulk tobacco into little mylar bricks.



Edited to add - I’m still new to all of this, so I could be screwing the pooch, likewise. At least you figured out your issue before it got out of hand!
 
Last edited:

Casual

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Here’s a business idea. Please tell me why it sucks.

Since people are worried about sales being heavily taxed or prohibited in the future, but home cellaring has risks, what if the big online vendors added a cellar service.

You send them $10 to buy a tin, and rent a locker in their controlled storage facility for an annual fee. They have professionals that check things periodically and the annual storage fee includes an insurance rider that means they’ll replace tins that go bad. And if sales are prohibited later, that’s fine, you’re not buying anything when you deduct tins from your cellar. It’s like an old timey bank under the gold standard, but for tobacco.

Maybe they even post a bond that allows the return of all tobacco to the owner in the event of a bankruptcy.

 

germinal

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Mar 18, 2021
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Interesting, thank you kindly for sharing. I've been storing unsealed (paint can style) tins and pouches in mylar and have been meaning to put square tins in mylar too but this certainly gives pause.

Or, I guess it could be said, that if the tins rust while sealed in a bag, then so what? They're sealed in a bag, right? If the seal breaks down on a tin that is otherwise cut off from air, then the worst thing that can happen would be... what exactly?

Haha I got the image of a pile of rust mixed with a pile of tobacco in an unsmokable mess. But that is true, the tin will work just like a oxygen absorber so the rusting will probably be self limiting at some point. It will probably affect the second hand value though if that is of consequence.

Toss one of these in with every bag and make sure to vacuum seal, not just seal. No oxygen = no rust.

The oxygen absorbers linked will if my calculations are correct absorb about 0.026 us gallons 🤓 so pulling a vacuum is probably good with those. And as cosmic mentions they will probably rust in lock-step with the tin.

Anyone tried a basic foodsaver vacuum with mylar?
 

BarrelProof

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Interesting, thank you kindly for sharing. I've been storing unsealed (paint can style) tins and pouches in mylar and have been meaning to put square tins in mylar too but this certainly gives pause.



Haha I got the image of a pile of rust mixed with a pile of tobacco in an unsmokable mess. But that is true, the tin will work just like a oxygen absorber so the rusting will probably be self limiting at some point. It will probably affect the second hand value though if that is of consequence.



The oxygen absorbers linked will if my calculations are correct absorb about 0.026 us gallons 🤓 so pulling a vacuum is probably good with those. And as cosmic mentions they will probably rust in lock-step with the tin.

Anyone tried a basic foodsaver vacuum with mylar?


No clue. But if your math is correct, that’s over 3 ounces that it’s capable of absorbing. I think you’d have bigger issues if you’re trying to store a tin with more than 3 ounces of liquid in it.
 

germinal

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Mar 18, 2021
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No clue. But if your math is correct, that’s over 3 ounces that it’s capable of absorbing. I think you’d have bigger issues if you’re trying to store a tin with more than 3 ounces of liquid in it.

My mylar bags are ca 8 inches by 12 inches and should be, briefly comparing to similar products, about 0.5 gallons. So if blown up like a balloon with no tobacco you would need a few of those. But in practice there will probably be no issues.
 

BarrelProof

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My mylar bags are ca 8 inches by 12 inches and should be, briefly comparing to similar products, about 0.5 gallons. So if blown up like a balloon with no tobacco you would need a few of those. But in practice there will probably be no issues.

Definitely. And to my point, I’m suggesting they’re used after vacuum sealing, which should make them at least somewhat viable.
 

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