Mylar and 02 ???

[lildrestl3]

Ok I ordered Some mylar and 02 absorbers... After I Fill The Mylar and drop in The absorber Should I get most of the Air Out before sealing? Any Vids On Useing Mylar on Here I looked for some... Thanks Dave

[MikeK]

Just squeeze out as much air as you can and seal. Avoid the temptation to vacuum seal. O2 absorbers don't work right in a vacuum and mylar isn't designed for it anyway. The O2 absorber will do the rest.

You might try an electric hair straightener for sealing the bags. I found it works smoother, easier, and makes a wider seal than the iron method.

[MR_SLOW]

I vacuum seal my Mylar bags with a Food saver. I use a 2000 cc Oxygen Absorber inside the bag. I don't want the oxygen absorber to work since it is not needed. In a few year I will be opening the bucket. Inside will be a perfectly good oxygen absorber. I might not have the food saver or electric power if I want to reseal the Mylar bag. If the Mylar bag was to leak the oxygen absorber would start to work. The bucket itself would now be the final protection since I use Gamma lids which are air tight.

Oxygen Absorbers don't work under negative pressure or a 29 inch vac.A oxygen Absorber will get hot if its working right. You can use hang warmers instead of using oxygen absorbers.

Mylar bags can hold a vacuum.

[Ladysurvivalist]

I'm on a shoe string budget. Just like MikeK, I squeeze out as much air as I can by hand. The mylar bag is put against my husband's metal level which is supported by 2 buckets underneath. Then I seal it with my hot iron (on "linen" heat) along the lip or top edge of the mylar bag.

I place 2 O2 absorbers in each mylar bag. One at the bottom and one at the top after it's filled with the contents. Within 24 hours after sealing, my mylar bag is brick hard.

[lildrestl3]

Originally Posted by MikeK

Just squeeze out as much air as you can and seal. Avoid the temptation to vacuum seal. O2 absorbers don't work right in a vacuum and mylar isn't designed for it anyway. The O2 absorber will do the rest.

You might try an electric hair straightener for sealing the bags. I found it works smoother, easier, and makes a wider seal than the iron method.

I seen the Dollar Store Has Hair Straightner for 11 bucks... I have 20 of the 1 gallon Bags and 100- 300 cc o2 absorbers on the way... Its a Start... The bags are 10x14 7mm mylar

[stephpd]

Originally Posted by MR_SLOW

I vacuum seal my Mylar bags with a Food saver. I use a 2000 cc Oxygen Absorber inside the bag. I don't want the oxygen absorber to work since it is not needed. In a few year I will be opening the bucket. Inside will be a perfectly good oxygen absorber. I might not have the food saver or electric power if I want to reseal the Mylar bag. If the Mylar bag was to leak the oxygen absorber would start to work. The bucket itself would now be the final protection since I use Gamma lids which are air tight.

Oxygen Absorbers don't work under negative pressure or a 29 inch vac.A oxygen Absorber will get hot if its working right. You can use hang warmers instead of using oxygen absorbers.

Mylar bags can hold a vacuum.

Again we see poor advice being given about vacuum sealing, O2 absorbers and Mylar.

First Mylar isn't designed to work with a vacuum. Nothing is gained and much is lost be doing this. If it were a better way manufacturers would be doing it but don't.

As to O2 absorbers I'll repost some simple math that I did for another thread and then you figure which is better.

A vacuum sealer usually only achieves ~20-22" of mercury. Or only removes ~66% of the air.

For some simple math let say the container is 1000 cc's. Applying a vacuum with a vacuum sealer will still leave 333cc of air. 20% (oxygen in air) of that would be 66 cc's.

By comparison an O2 absorber can remove up to 99.99% of the O2 leaving only .1 cc of O2 (typical O2 levels are .01% or less) and at far less of a vacuum of only about 6" of mercury.

Since nature hates a void (greater pressure differential) it tries harder to infiltrate a high vacuum bag then a low vacuum bag. Or it tries 3 to 4 times harder to get into a vacuum sealed bag then one that uses an O2 absorber.

So, would you prefer .1cc of O2 or 66 cc's of O2 around your food? Since O2 absorbers don't work well, if at all, in a vacuum you will still have all that O2 around your food.


Given the choice of an O2 absorber or a vacuum from a home vacuum sealer (foodsaver or such) the O2 absorber does a much better job of removing O2 from the air. Well worth the cost in my opinion since oxidation of food is one of the main causes of spoilage.

[Cumulunimbus]

Originally Posted by stephpd

Again we see poor advice being given about vacuum sealing, O2 absorbers and Mylar.
First Mylar isn't designed to work with a vacuum. Nothing is gained and much is lost be doing this. If it were a better way manufacturers would be doing it but don't.
As to O2 absorbers I'll repost some simple math that I did for another thread and then you figure which is better.
….
So, would you prefer .1cc of O2 or 66 cc's of O2 around your food? Since O2 absorbers don't work well, if at all, in a vacuum you will still have all that O2 around your food.
…...

I am not so sure that MR_SLOW is the one giving poor advice on the matter of use of O2 absorbers in conjunction with partially vacuum sealing of mylar bags.

I guess Sorbent Systems would be a judge we all could agree to be a decent one in this dispute?

Well, what do they have to say?

http://sorbentsystems.com/longtermfoodstorage.html

Vacuum Sealers
You can seal bag up to 10 inch wide, and the vacuum in fact removes enough air to allow the use of a smaller oxygen absorbers. To guarantee a three years minimum shelf life, we still recommend a 300 cc Oxygen Absorbing Packet.

(The “10 inch” remark relates to the use of one of their heat sealers.)

[stephpd]

I use that page as a reference numerous times. What some folks seem to be confusing is two different techniques and bags. Nowhere on that page do they show using a vacuum sealer and Mylar bags. They have several pictures on how to pack with Mylar, O2 absorbers and buckets, follow those instructions and you'll be fine.

The short paragraph on vacuum sealers is talking about a different thing entirely. Follow that link and you'll see the clear bags that everyone uses for vacuum packing. The O2 absorbers isn't for what's in the bag under vacuum but what will permeate over a few years, since all clear plastic bags, without the aluminum foil found in Mylar bags, will permeate air. The O2 absorber only extends the shelf life of clear bags from 2 ( all the bags are good for) to 3 years. That's not really long term but a much shorter term then the 10 or more you get from Mylar or the 30 or more you can get from metal cans or mason jars.

[Cumulunimbus]

Have you considered that your information might be partially outdated?

http://www.sorbentsystems.com/specs/pakdry7500.html

PAKDRY 7500 Back to Main Page

________________________________________
PAKDRY7500 is a 7.5 mil thick (minimum) high moisture and gas (oxygen, carbon dioxide et al) barrier film with a dual layer of both 48 gauge polyester and 60 gauge biaxially oriented nylon providing very high tensile strength and resistance to puncture, making this product suitable for vacuum packaging applications and for very large bags including cargo container liners. As an FDA approved substrate for food contact the 6.0 mil MINIMUM metallocene P.E. sealant layer has made this the product of choice for bulk food, fine pharmaceutical powders and medical device engineering specifications.

NOTE: Our PAKDRY7500 structure is 7.5 mils minimum with an FDA approved sealant layer.

[Lowdown3]

YouTube - Long term food storage part 1

Good luck!

[stephpd]

Nope, it's that most folks will be purchasing the thinner, 3.5 or 4.5 mil bags.Those can be subjected to pin holing if using a vacuum, causing leaks.

I've packed over 50 buckets (Nothing substantial, I know. But what most places selling superpails (or 5 gallon buckets) use is just what you see on that page. 4.5 mil bags, O2 absorbers and buckets and no vacuum), mostly with the 5-6 gallon bags like they show in the photos. I've also done a few with the thinner 3.5 mil 1 gallon bags. I've yet to even buy one of the 7.5mil bags for anything.

And I'd bet most here are the same way.

Go to the vacuum sealing page and all you'll see is the clear vacuum bags like the ones for a foodsaver machine.

I've yet to find a page, except for folks here and some youtube videos using a vacuum with Mylar bags. But not from the pros. Even some links for stuff not food, like museum storage, use the technique of Mylar and O2 absorbers without a vacuum.

[chuck s]

I personally do not feel that an O2 absorber is affected by a partial vacuum. There is still plenty of O2 left after applying a vacuum, so why would it not absorb that? However, I agree that there is no need to apply a vacuum before sealing a mylar bag when an O2 absorber is used, and indeed, the higher vacuum force may contribute to a bag failure. When sealed correctly, the o2 absorber will cause a mild vacuum in the bag as the decrease in O2 will lower the partial pressure inside the bag, creating the ideal environment for long term food storage.

[MikeK]

Originally Posted by MR_SLOW

I vacuum seal my Mylar bags with a Food saver. I use a 2000 cc Oxygen Absorber inside the bag. I don't want the oxygen absorber to work since it is not needed. In a few year I will be opening the bucket. Inside will be a perfectly good oxygen absorber. I might not have the food saver or electric power if I want to reseal the Mylar bag. If the Mylar bag was to leak the oxygen absorber would start to work. The bucket itself would now be the final protection since I use Gamma lids which are air tight.

A vacuum doesn't remove as much O2 as an O2 absorber would. So just using the O2 absorber in mylar would better protect the food. Secondly, O2 absorbers apparently have their own shelf life. 6-8 months if I remember right. They also contain a small amount of moisture to get the reaction started. Everything wants to reach equilibrium, so the dry food is going to act like a dessicant, removing the moisture from the O2 absorber over time. So you really aren't achieving anything this way.

The best advice is to just package foods like the food storage companies are doing it. They know what they're doing already. Trying to second guess the process leaves room for too many errors.

[MikeK]

Originally Posted by chuck s

I personally do not feel that an O2 absorber is affected by a partial vacuum. There is still plenty of O2 left after applying a vacuum, so why would it not absorb that? However, I agree that there is no need to apply a vacuum before sealing a mylar bag when an O2 absorber is used, and indeed, the higher vacuum force may contribute to a bag failure. When sealed correctly, the o2 absorber will cause a mild vacuum in the bag as the decrease in O2 will lower the partial pressure inside the bag, creating the ideal environment for long term food storage.

A partial vacuum perhaps. But where do we draw the line at "partial"? The O2 absorbers require the headspace gas to work correctly. Since there's no benefit to the vacuum, as the O2 absorber does a better job on it's own anyway, why trust it?

If it was a better method, the food storage companies would use it. We already know for a fact that what they are doing works. Do we know for a fact that what you suggest does? Why complicated things when there is no improvement to be gained? The combination of vacuum, partial or not, and O2 absorbers does not lower the O2 level more than the O2 absorber itself would have done. I see no benefit to the risk.

[tedennis]

Originally Posted by MikeK

The best advice is to just package foods like the food storage companies are doing it. They know what they're doing already. Trying to second guess the process leaves room for too many errors.

i agree. have only done 50 bags but still holding strong.

why fix what isnt broken?

[germantrader10]

I vacuum seal my Mylar bags using a food saver. It has been modified to seal Mylar. I also throw in a oxygen absorber packet. Holds fine and i think it will do the job.

[MikeK]

Originally Posted by germantrader10

I vacuum seal my Mylar bags using a food saver. It has been modified to seal Mylar. I also throw in a oxygen absorber packet. Holds fine and i think it will do the job.

So you're happy having more O2 in with your food, than you would have just using the O2 absorber alone? I guess I just don't see the logic. Apparently neither do the long term food storage companies.

[lildrestl3]

Originally Posted by Lowdown3

YouTube - Long term food storage part 1

Good luck!

Thanks for the Vids. Very Helpful so I guess 400cc per gallon of mylar? 2000cc for a 5 gallon bucket?

[chuck s]

Originally Posted by MikeK

A partial vacuum perhaps. But where do we draw the line at "partial"? The O2 absorbers require the headspace gas to work correctly. Since there's no benefit to the vacuum, as the O2 absorber does a better job on it's own anyway, why trust it?

If it was a better method, the food storage companies would use it. We already know for a fact that what they are doing works. Do we know for a fact that what you suggest does? Why complicated things when there is no improvement to be gained? The combination of vacuum, partial or not, and O2 absorbers does not lower the O2 level more than the O2 absorber itself would have done. I see no benefit to the risk.

did you read my statement? I do not complicate things. I fill the bag up, get rid of excess air by pressing down on the bag after dropping in an O2 absorber and seal it. The O2 absorber then creates the partial vacuum.
A total vacuum would be impossible to create, so any vacuum created by a food sealer type system can only create a partial vacuum and I can find no scientific evidence that this makes an O2 absorber ineffective, head space only means that the O2 absorber is not surrounded by a vacuum sealed enclosure, so laying on top of the grain negates this situation, but again I agree it is not needed and may be detrimental to the integrity of the bag. As far as food storage companies knowing for a fact that their method is best, I can find no evidence of that either.

[BOBSTOUT]

not to hijack but i got a bunch of handwormers at wallofchinamart 4 for 10 cents can i use them in 5 gal instead of several 02 absorbers that would be great

thanks for info

BOB