# Mylar bags and food storage



## Prepper345 (Feb 3, 2020)

Hi I am new to the forum and would love for ppl to tell me what brand of mylar bags, oxygen absorbers ect they use for long term food prep. I'm days into my journey but want to learn fast to have a food storage set up


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## paulag1955 (Dec 15, 2019)

I searched for "mylar bags" and this thread turned up. I feel bad that no one responded to the original question, but I'll not be deterred from my purpose of asking a question.

Can anyone give me an estimate on how many pounds of flour can be stored in a 5 gallon mylar bag? How big an oxygen absorber would be needed?


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## Back Pack Hack (Sep 15, 2016)

Here ya go:

https://www.usaemergencysupply.com/...-storage/oxygen-absorbers-recommended-amounts


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## paulag1955 (Dec 15, 2019)

Thanks!


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## paraquack (Mar 1, 2013)

One tid bit of a suggestion. If you decide to store large quantities of ddry goods in Mylar bags, 
I suggest you spend a few extra peenies for bags with zip lock closures. When you have to 
open the bag, the ziplock feature keep the food in the bags, and bugs and such outside the bag. 
It also helps during the heat sealing operation by prevent the food from contaminating the area 
to be sealed. Nothing worse than goin thru the steps only to find out the seal wasn't good due 
to food dust preventing a good seal.


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## Kauboy (May 12, 2014)

I can't help you with brand names, but can give you some things to look for.
You want Mylar that is intended for this purpose. It will have an inner layer of polyethylene that allows for the thermo-sealing we are looking for.
I don't recall, but I don't think emergency blankets made from Mylar have this layer, so they would not work as an improvised source. I could be wrong on this.

For O2 absorbers, you will want various sizes due to variance in the amount of air you'll have to deal with depending on the food you are storing. For example, there is more air between dry beans than between grains of rice. You might fill up the same size bucket for both, but one will have more air than the other. Keep these O2 absorbers sealed until ready to use, or they will be be used up and ineffective within hours.
You can also use hand warmers for this function, since they are basically the same thing. You should still note the size differences though.
More is better than less. It might be wasteful, but it's better to be safe than sorry. If I'm unsure about the amount needed, I toss in another pack or two. You can find charts and calculations all over the internet for how many O2 packs to use for the air volume you expect.

For the process, use clean buckets that you know have never been used to store chemicals, like oil or fuel, as these will leech into the plastic, and then potentially back into your food.
It is claimed that you can get away with non-food grade buckets if you are using Mylar bags. Just be sure you know what they held before you acquired them if they aren't new. I stick with new food grade for added assurance.
Open a Mylar bag and place it into your bucket. Slowly fill the bucket, stopping to shift and settle it as you go, until you are almost to the bucket's rim. You will need to ensure you have enough Mylar left at the top to seal with.
You can use various methods for sealing. I've used an old hand iron and a small board placed across the mouth of the bucket. You can fold the mylar over the board and get a good press with the iron this way. Lately however, I've taken to using an old hair straightener my wife no longer uses. I set it to 350 and can control the seam with precision.
Best practice is to seal the opening 3/4 or more of they way, get your O2 absorbers ready (out of their sealed container) and primed (I shake them for a few seconds to break up any clumps) and toss them in the small opening that's left. Then compress the bag down to force out all the air you can, keeping the small opening easily accessible. Once everything is pushed out, seal it up with a final swipe. Double check your seam for any wrinkles or bubbles, and give them another pass or two. At this point, the rush is over. The bags should be sealed, and the O2 absorbers have already started their work. No need to seal the buckets yet, and I don't recommend it at this point.

You want to keep an eye on the bag. Over the next hour or two, you should notice a reduction in the air pocket that is at the top. If you did a really good job of squeezing out the excess air, you may even start to see the Mylar suck up against the food inside and get really tight. This is a good sign that your O2 absorbers are good and your seal is working. That's why we leave the bucket lid off. With this confirmation, we can be confident in our storing process, and we can proceed with sealing up the bucket.
However, if we do not see this happening, it means one of two things. Either our O2 absorbers are bad or we didn't add enough, or our seal is not airtight. One way to eliminate the first possibility is to wait for the O2 absorbers to heat up a bit before you put them in the bag. This is part of what I call "priming". They should start to get warm within 30-60 seconds if they are still good. They get hot because of the exothermic reaction between the iron in the packets and the O2 in the air.
If you checked this, and your bags did not shrink up at all, you have a leak in your seal or you didn't add enough O2 packets for the volume of air that was left in the bag.
Your only option is to recheck your seal or reopen the bag and try to fix the issue. Depending on how much extra bag you have, you may or may not be able to remedy the problem with a small cut, adding a good O2 packet or two, and resealing the cut.
If you don't have extra loose bag to work with, you're looking at needing to transfer into another bag and try it all over again. Or, pouring out enough to get some excess bag to reseal with.

For lids, if you are using Mylar, the bucket itself doesn't need to be airtight. However, there is another benefit to using a gasket sealing lid over a simple snapping lid. Weight capacity goes up by over 50% when using a stronger gasket lid versus a simple snapping lid. I found an article that said a bucket can hold ~550lbs of stacked weight if using a gasket lid, and only ~308lbs if using a snapping lid. So you can stack them higher if needed. Then you have that monster of a lid, the "Gamma Seal" lid, and that can likely hold even more. (I only recommend this lid for buckets you will be getting in and out of, for things like salt or sugar)

That was long. I hope it helped.
Feel free to ask any questions. Lots of folks on here do this, and somebody should be able to answer.


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## paulag1955 (Dec 15, 2019)

Kauboy said:


> I can't help you with brand names, but can give you some things to look for.
> You want Mylar that is intended for this purpose. It will have an inner layer of polyethylene that allows for the thermo-sealing we are looking for.
> I don't recall, but I don't think emergency blankets made from Mylar have this layer, so they would not work as an improvised source. I could be wrong on this.
> 
> ...


Wow, that's what I call an exhaustive response!


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## Kauboy (May 12, 2014)

paulag1955 said:


> Wow, that's what I call an exhaustive response!


I just finished doing it for 3 buckets myself, so it was fresh on the mind. :tango_face_smile:


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## paulag1955 (Dec 15, 2019)

Kauboy said:


> I just finished doing it for 3 buckets myself, so it was fresh on the mind. :tango_face_smile:


I'm having 50 pounds of flour delivered in the next couple of weeks, and I want to be ready to get it properly stored. I got a 50-pound capacity dog food vault with a gamma seal that's made from food grade plastic, but I still want to put the flour into mylar bags inside the vault.


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## paraquack (Mar 1, 2013)

paulag 1955, what kind of material is the dog food vault? There are only a couple of plastics 
that don't leak gases. Really curious since everything I have read says "heavy-duty HDPE". 
But HDPE is not gas tight in the long run, only Mylar or PETE.


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## paulag1955 (Dec 15, 2019)

paraquack said:


> paulag 1955, what kind of material is the dog food vault? There are only a couple of plastics
> that don't leak gases. Really curious since everything I have read says "heavy-duty HDPE".
> But HDPE is not gas tight in the long run, only Mylar or PETE.


That's why my plan is to use mylar inside the vault.


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## Mad Trapper (Feb 12, 2014)

Glass is better, but not so compact. They stack well too.


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## paulag1955 (Dec 15, 2019)

Mad Trapper said:


> Glass is better, but not so compact. They stack well too.


I live in earthquake country, so there's that. You could lose a lot of stores due to broken glass.


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## paulag1955 (Dec 15, 2019)

Question. I have 5 gallon zip loc Mylar bags in which I want to store flour. I know the zippers aren't air tight, but I intend to store the Mylar bags in a dog food vault with a gamma seal lid. If I put oxygen absorbers inside the Mylar bags and close the zippers, then put the Mylar bags into the dog vault, then put oxygen absorbers in the food valut and close the gamma seal lid...am I good?


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## paraquack (Mar 1, 2013)

The ziplock will leak, how fast is anybody's guess.  But I bet with in a week or so. 
I had 2 mylar bags with a barely visible pinhole, I found the hole after the bag of 
rice initially deflated at oxygen was consumed but then began to inflate a bit after 
7-8 days. Mylar (BoPET) and PETE are almost completely Gas (oxygen) proof. 
HDPE and PE and other plastics are not as good as Mylar or PETE in preventing 
oxygen to diffuse (move back and forth depending on concentration). If the vault 
is not PETE it will allow oxygen and other gases to move through it.

Check the difusion rates for oxygen in HDPE and PETE
Plastics Comparison Chart | Alpha Packaging

Mylar
https://xamax.com/polyester-films/
https://polymerdatabase.com/Films/PET Films.html

EDIT: A tightly sealed but with oxygen absorbers will collapse as the oxygen is consumed. 
But don't think it won't diffuse oxygen. Plus the bucket could collapse sufficiently to cause
micro cracks in the plastic, so it actually leaks.


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## paulag1955 (Dec 15, 2019)

paraquack said:


> The ziplock will leak, how fast is anybody's guess. But I bet with in a week or so.
> I had 2 mylar bags with a barely visible pinhole, I found the hole after the bag of
> rice initially deflated at oxygen was consumed but then began to inflate a bit after
> 7-8 days. Mylar (BoPET) and PETE are almost completely Gas (oxygen) proof.
> ...


So I think what you're saying is that my best bet is to heat seal the Mylar bags with oxygen absorbers, then store those in the dog food vault, but no oxygen absorbers in the dog food vault?


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## paraquack (Mar 1, 2013)

You got it. I got to the bakery and buy their 3-1/2 to 5 gallon pails with lids for about $0.50 each. 
They are food grade, they smell great, unlike pickle pails. I can stack them 6 high with no problems, 
and with the bail, They are easy to grab and go. I can get between 3-4 1 gallon mylar bags in each, 
3 standing up and sometimes one across the top, laying down in each 5 gallon pail. I try to stay 
away from the 3-1/2 gallon pails, too short except for the small Mylar bags of spices.


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## paulag1955 (Dec 15, 2019)

paraquack said:


> You got it. I got to the bakery and buy their 3-1/2 to 5 gallon pails with lids for about $0.50 each.
> They are food grade, they smell great, unlike pickle pails. I can stack them 6 high with no problems,
> and with the bail, They are easy to grab and go. I can get between 3-4 1 gallon mylar bags in each,
> 3 standing up and sometimes one across the top, laying down in each 5 gallon pail. I try to stay
> away from the 3-1/2 gallon pails, too short except for the small Mylar bags of spices.


Thanks!


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