Sunday, August 18, 2013

Long Term Food Storage: Mylar Bags

I plan on doing a couple of posts on long term food storage.  Since I have been playing with mylar recently, I figured I should start with that.

The purpose of mylar bags for the prepper is to store dry goods for long term.  Mylar is impermeable to light and can be sealed air tight with a simple application of heat (vacuum food sealer machine, hair straightener, clothes iron) across the open end of the bag. At the most basic description, mylar bags are layers of plastic and foil laminated together to make it impervious to light, air, and moisture; these being three of the four things we try to protect dried food from to extend storage life. The fourth thing being heat.

Since you want to keep out light (the easy part), moisture and air (specifically the oxygen part), a mylar bag is frequently paired with an O2 absorber and occasionally a desiccant (moisture absorber).  If your storage food is sufficiently dry, only an O2 absorber is needed.

The most common sizes are the 1 gallon and 5 gallon bags.  The 5 gallon bags have the convenience of a one bag 5 gallon bucket.  The drawbacks are... 5 gallons of beans is a lot to open and use all at once.  The 1 gallon bags are convenient sizes for use, but are less convenient for storage as you really can't get 5 bags in a 5 gallon bucket.  You have to decide what will work better for you when the time comes to use the food.  If you have or plan on a large prepper group, 5 gallon bags in buckets probably have no real drawbacks for you.  My personal choice is the 1 gallon size.  An open bag has less of one type of food that needs to be used up quickly and allows for a variety to be stored in a 5 gallon bucket with spaces between the bags for other supplies (condiments, spices, plastic utensils, etc).

Food items suitable for storage in mylar bags are beans, rice, flour, sugar, oats, pasta... see the trend?  Small grains and legumes that are generally stored dry.  Some preppers have had trouble storing grains that are sharp (popcorn, some pastas) as they will puncture the mylar.  If you want to store these items, you can leave them in their original bags (or a zip top type bag) so the bag is padded from the sharp ends of the food being stored.  Just be sure that your O2 absorber can draw the air from around the pasta or corn by puncturing its original plastic bag in a couple places or by not sealing the zip top bag completely.

The basic instructions for use:
-fill the bag (not completely, leave some room for sealing), drop in an O2 absorber, then seal the mylar.  That's it.  After sealing, be sure the bag is in a secure, safe place and let it go.  Keep it in a stable, cool, environment for maximum storage life of the food items.

The details:
-fill the bag:
Put in the food (in this case white rice) and an oxygen absorber.  Leave enough room to be able to seal the top and have a little extra (I'll explain why in a moment)

 -seal the bag:
I have tried a couple of methods for this and settled on one.  First the not-so-best-choice ones:

the food sealer:

Notice the thin line of seal below a lot of wasted space?  I didn't like the wasted space, nor did I like the thin seal line on this one.

the thicker seal with space above:

This has a thick seal space with a small amount unsealed on top.  There is no reason for the unsealed top since you can't pull the bag open.

the one I settled on:

This one shows the seal I settled on along with some technique used.  This is a top seal that is about 1 1/2 inches deep. 

The sealing process:

These bags fall over very easily making a mess.  I put the bags in a box that is just the right height for them.  This way I can fill several, drop in the oxygen absorbers, then seal them all quickly.  When I have 4 full one gallon bags (what fits in my box), I put my wood stick on the edge of the box, bend the top over and use a regular clothes iron on high to close most of the bag up.  I then insert a straw, suck out as much air as I can, hold the top closed while pulling out the straw out and applying the iron to the last couple inches.  You don't have to pull all the air out, the O2 absorber will finish the necessary parts for you.

Once they are sealed, label (food and amount) and date them (I know I won't be remembering what and when next week, let alone in 10-20 years) and set them aside.  After a short time (say... a day...) the oxygen will be absorbed from the inside of the bag and you should see a good seal:

Here are a couple things I have learned from reading various blog posts and forum threads, then from doing:

- don't fill the bag completely.  Leave some space below the seal, so, if for some reason you need to, you can cut the sealed top off (the only way to open this), then reseal the bag without wasting it.  You could mess up the seal, forget the O2 absorber (ahem... no... I've never done that...), or need to open it to use just a part of the product.  If you leave a bit of room, you will be able to reseal the bag.  If you fill it to the top, or seal it to the top of the food, you won't be able to just reseal it without removing some of the product.

-oxygen absorbers work as soon as they are exposed to air.  To keep them fresh and functioning, keep them out of the air (simple enough).  My method: put my spare ones in a small glass jar.  I drop them in, fill the rest of the jar with beans (less air left to waste their functioning power), the snug down the top.  It looks like this:

In review: have your product, bags, O2 absorbers, hot iron and sharpie ready to go.  If you are opening a new bag of absorbers, have a plan on what you are doing with the extras that aren't needed for this session.  Bag the product, drop the absorber in, seal the bag, label the bag, then record the item somewhere so you know what you have in storage without having to check and count bags.

Friends, this is simple, cheap, and easy.  I suggest doing it now while food is cheap.  So now... WWYD?

What have you sealed up?  How do you store it?  Have you run into any problems or learned a technique that others can benefit from?  I would love to discuss it with you in the comments.

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