What Should I Do?

Grain in Buckets

Food Storage Packing: Facts and Myths

Friday, February 3, 2012, 12:39 AM
Know the facts about do-it-yourself packing

The purpose of this article is to present specific details and recommendations for packing your own shelf-stable foods for food storage. We will cover what works and what doesn’t in creating an oxygen-free atmosphere for long term food storage, and common misconceptions about how to do your own packing. While there are many different types of dried foods that can be stored for extended periods of time, most folks are interested in how best to store grain and bean products.

While I could write a book on every specific detail of every packing option and all of the technical specifications of all available packing containers, that is not the purpose of this article.  I will cover important highlights, facts, insights, and information gained from over 37 years in the preparedness and outdoor recreation industry.  It is important to keep in mind that I have not only been a retailer of preparedness and outdoor foods, I have also been a manufacturer, developer of hundreds of recipes, packaging and product  innovator, and researcher of shelf-stable foods.

Some of the material presented here will contradict and challenge information available on the Web or in some do-it-yourself circles.  Many people assume preparedness information to be accurate without careful consideration of the source's expertise or the validity of the facts.  I encourage you to research on your own any of the information presented in this article – or in any article, for that matter – and to use basic critical thinking skills to evaluate the evidence and data you are offered.  A little common sense goes a long way in assessing many of the claims being made about shelf life and do-it-yourself issues. 

Basics

Before you start packing your foods, be clear about what it is you want to store and for how long.  Are the foods appropriate for your plans?  Do you know how to prepare them?  Do you have an adequate quantity?  Do you have all the equipment necessary to prepare your foods?  What is the nutritional quality?

This article deals with dry food products with a low to very low moisture content – depending upon the item, this is usually between 2 and about 10%.  Products can include grains, beans, seeds, dehydrated or freeze-dried fruits and vegetables, seasonings, and powders and flours.

Grains and beans can be whole or processed into numerous forms.  Keep in mind that when a whole grain or bean is processed, it can compromise the integrity of a natural barrier, expose any oils, and begin a process of oxidation or rancidity leading to a shortened shelf life.  Some processed bean products, such as TVP (Textured Vegetable Protein), have been de-fatted to insure a longer shelf life, and some grains have naturally lower oil content.  Because of the position of the germ in rice, brown rice is not appropriate for long term storage (it has about a 6 month shelf life).  Also, because white flour has no wheat germ, it will last significantly longer than whole-wheat flour.  Research the products you are storing to determine both the moisture and oil content.

What are the goals and expectations for your food preparedness planning?  What are you hoping to accomplish, and for whom, and how many?  How realistic are your plans?  How long do you want your stored foods to be palatable – edible – nutritious – agreeable?  Be honest and make thoughtful decisions about your food preparedness goals. 

Why oxygen-free?

At the end of this article I have included information on the six critical conditions for storing food.  In this section we explore the need for an oxygen-free atmosphere when storing food for long periods.  Basically, there are two reasons for wanting to store food in an oxygen-free environment – to eliminate the possibility for infestation from insects and microorganisms, and to control oxidation, which leads to the rancidity of fats and oils, foul taste, off color, and nutritional deterioration.  The lower the oxygen levels, the more effective in preserving the integrity of the foods stored. 

Some foods are more susceptible to oxidation deterioration than others.  It is important to know how susceptible the foods you are storing are to oxidation, because as you will see, the type of container you store your foods in may at some point no longer be an adequate oxygen barrier.  Research by Mitsubishi Gas Chemical Company, the inventors of oxygen absorbers and manufacturer of the Ageless® brand absorber, indicates that in an oxygen-free atmosphere (their absorbers can reduce the residual oxygen level in the proper container to 0.1% or less), all adults, larvae, pupae, and eggs of the most prevalent dry food insects are killed within 14 days.

If oxidation and elimination of all stages in an insect’s development by eliminating available oxygen is not an issue, there are other methods that can be utilized with varying effectiveness in controlling insect infestation.  Options include:

  • Exposure to freezing temperatures for an adequate length of time (this may kill adults and larvae but not all eggs)
  • Using bay leaves and other aromatic herbs to inhibit insect reproduction
  • Using food-grade diatomaceous earth to kill adults.  (The microscopic, very sharp texture of the particles pierces the bodies of the insects and they dehydrate and die).  In this case, the live adult must come into contact with the diatomaceous earth.  Some folks put the material on the bottom of a container, hoping the insects will go there, while others coat all the contents of a container with a fine layer of material and wash it off when it is time to consume the food.
Methods of reducing residual oxygen levels when you pack your own
Utilize an oxygen absorber properly

(Also see the very informative article Using and About Oxygen Absorbers.)

Pro:

  • Very effective in reducing residual oxygen levels – in my opinion, it is the most effective technology available today

  • Relatively inexpensive and easy to use if done properly

  • Harmless components – iron oxide

  • Easily obtainable

Con:

  • This product was developed for use by professional food companies that understand how to properly use and store it.  There are important guidelines which must be followed for the absorber to work properly and not lose its effectiveness.  The do-it-yourself person will defeat the purpose of using this technology if the guidelines and instructions are not properly followed.  It is imperative that the absorber user obtain all necessary information from a qualified supplier on its correct use. (Using and About Oxygen Absorbers)

  • The absorber user needs to do their homework and make sure the correct-sized absorber is being utilized for both the size of the container and food product packed.
Insert a wand into a pouch, can, bucket, or jar and attempt to replace the atmosphere by squirting it with nitrogen (the most commonly used inert gas)

Pro:

  • Fairly easy to do
  • Relatively inexpensive

Con:

  • Without the proper testing equipment, there is no way for the pack-your-own person to know the residual oxygen levels of their containers.  If the levels are too high, you have defeated the purpose.  How much nitrogen to use and the length of time to insert it into the container are both speculation and assumption.  Do you want to rely on guesswork?
  • When removing the wand and sealing the container, some amount of oxygen will be introduced into the container, which will affect the atmosphere in the container.
  • To achieve the desired effect of a very low residual oxygen level, this method has many weaknesses. 

    (NOTE: Before the days of the oxygen absorber, companies such as mine used elaborate equipment designed to draw a vacuum and nitrogen flush in a chamber.  The goal was a residual oxygen level of 2% or lower, because this was the military specification for long term storage of foods in a #10 size metal can.  Even with the proper equipment, reaching these residual levels required experience, testing, and effective methodology.  Can “wanding” by hand achieve these levels?)

The dry ice method

There was a time (and there may still be) when folks would put dry ice at the bottom or top of a container, leave the lid slightly ajar, wait for the ice to evaporate, and then seal the lid.  This method has so many problems that I won’t bother to give it pros and cons.  It is not recommended.

Use a home model vacuum sealer with either a plastic pouch or available attachment to put over a jar

Pro:

  • Equipment is easily accessible
  • Can be effective for short term storage
  • Easy to use

Con:

  • Equipment and extra pouches can be costly
  • The vacuum pulled (measured in inches of mercury) may be helpful for short term use; however, is neither strong enough nor effective for a long term storage requirement.  The plastic pouches and jar seams are not designed to hold a vacuum for extended periods (longer than 1-2 years).
Go to a cannery

You can do your own canning of your own product in #10 metal cans.  Some canneries will sell you cans and bulk foods. Read the WSID article from Adam about his experience at an LDS Cannery.

Pro:

  • Very effective method for long term food storage – metal cans are the best containers
  • Depending on the cannery, costs can be low for using the equipment
  • You can easily insert an oxygen absorber into the cans for maximum shelf life

Con:

  • While metal cans are the most effective containers, they can be costly and very difficult to obtain in smaller quantities
  • Canneries are not readily available to most folks – most are sponsored by members of the Mormon Church, check on usage and membership requirements, hours of operation, and costs at each cannery
  • You’ll need the proper vehicle to transport bulk foods and cans
Use a manually operated or electric, smaller model open-top can-seam sealer

Pro:

  • Very effective method for long term food storage – metal cans are the best containers
  • You have significant flexibility as to when to use the sealer, and with whom it is to be shared
  • You can easily insert an oxygen absorber into the cans for maximum shelf life
  • They are easy to use once you get the hang of it

Con:

  • They can be expensive
  • You must do your homework to determine the best manufacturer and model
  • You must make sure you are operating them correctly and that the seams are being sealed properly
  • You need access to a supply of cans
Containers

Of all the issues relating to packing your own shelf stable foods, the most effective container to use can be the most confusing and misrepresented.  As stated in the beginning of this article be clear about what you are storing, how much, and for how long.

Plastic buckets (HDPE – high density polyethylene)

5 and 6 gallon round and square sizes with handles are very popular for packing grains, beans, and other commodities in bulk

Pro:

  • A convenient container to store larger quantities of dry foods – stores and stacks well, is compact, and can be carried easily
  • Inexpensive new and can be obtained used from a number of sources
  • A thick walled (90 mil) container with the proper gasket can be used effectively to control the atmosphere within for up to 1 to 3 years
  • Can be used in conjunction with foil pouches for convenience of storage
  • You can use multiple foil pouches stored in the bucket for convenience of use
  • Insects don’t easily penetrate the thick walls
  • Can withstand some rough handling
  • Because insects at all stages are destroyed within about 14 days, the short-term effectiveness of using an oxygen absorber to create an oxygen-free environment is useful

Con:

  • HDPE is a permeable (porous – albeit microscopic) material and gas transmission rates (the length of time gases such as oxygen will travel through a given material) indicate that it will take 1 to 3 years for the atmosphere within the bucket to match the atmosphere outside (our normal atmosphere is normally about 21% oxygen and 79% nitrogen, with a very small amount of other gases, such as carbon dioxide).  This means that if you started with an oxygen-free or low level to begin with, over time the oxygen level in the bucket will continue to increase until it reaches parity or equality with the normal atmosphere.
  • If you want the atmosphere to remain constant inside your container or be oxygen-free for extended periods of time, HDPE plastic buckets are not appropriate – check with the manufacturers (as I have done) and find out their specifications and recommendations for your needs and the specific container you want to use.
  • The ability to maintain whatever atmosphere you desire within the container will depend not only on the quality of the HDPE walls, but also the integrity of the gasket seal.
  • HDPE will absorb odors and they will eventually permeate into the contents of the bucket.  Direct packed foods will also absorb the odor.  Do not store plastic buckets in areas that have a strong smell. (NOTE: Foil pouches within a bucket will prolong the odor absorption)
  • Rodents and other animals can easily break into plastic buckets.
  • Not recommended for long term storage (3+ years) of directly packed foods.
Pouches

There are literally thousands of possible combinations of materials and sizes available to create a pouch that will contain food.  Normally a food manufacturer or packer goes to a company that specializes in manufacturing pouches and gives the company their specifications and requirements for the specific foods to be packed.

(IMPORTANT NOTE:  It is common these days among those who sell empty pouches for food storage, or food already in pouches, to use the term “Mylar pouch.”  This is very misleading.  By itself, the term can mean anything and it tells you nothing of importance so that you can make the appropriate decisions on what pouch to use.  The “Mylar” brand is the registered trademark name of a PET polyester film manufactured by DuPont Teijin Films.  They produce hundreds of variations of this polyester resin material.  It is a component used in the production of many variations of packaging material.  It can be clear or opaque, such as in wrappers for food bars or Mylar balloons that look “metalized” yet contain no foil.  Mylar by itself is not an appropriate material for long-term pouched food.  Ask your supplier what they mean when they say “Mylar.”)

For those reading this article, the requirements needed are to pack dry foods for the long term.  If you buy stock pouches from a distributor, you need to tell them what you plan to put in it and what your expectations are for the long term.  You should insist on knowing the specifications (especially the gas and vapor transmission rates) of the pouch and whether they suit your needs.

If you want a pouch that gives you the longest possible shelf life for your foods, you will need a laminated pouch consisting of multiple components and layers.  As far as pouches are concerned, one of those layers must be foil (NOTE: All plastics are gas and vapor permeable – some rates are very high – meaning that gases transmit through them very quickly – and some plastics both individually and in combination have slower rates).  Only quality foil is a non-permeable gas and moisture barrier – that is foil without microscopic holes)

Ask the distributor the specifications of the pouch; the different components used, not only for barrier properties but also for durability; the transmission rates, if not foil; if foil, its thickness; and the reliability and reputation of the manufacturer.

Pro:

  • The variety of available sizes offers flexibility in choices of quantities to store.
  • Costs are reasonable.
  • Can be effective as a short term oxygen free container
  • Small pouches of food can be very useful for bartering and distributing among those in need during in an emergency.

Con:

  • Not recommended for very long-term packaging of products for an oxygen free environment.  Shelf life of pouched foods is recommended for 3 to 10 years, depending on type of food product, storage conditions, handling, and composition of packaging materials.
  • Excessive or rough handling, loss of seal integrity, and pressure of sharp edges on the pouch from the products within can create “pin holes” (microscopic holes in the pouch material) that eventually will cause gases to be transmitted through the pouch. (NOTE: I am concerned when I see and hear some folks instructing people to cram and squeeze foil pouches into plastic buckets).
  • Rodents and other creatures can easily penetrate pouch material.
Metal cans

For food storage purposes, #10 size (about 7/8 gal) and #2½ size (about 7/8 qt) are the most popular and must be used with the proper can sealers.  It is possible, if you keep searching, to find 5 gallon square metal cans with a large pressure lid on the top side.  These are ideal for bulk food storage, although they may be hard to find (NOTE: I sold these cans packed with foods at AlpineAire Foods about 20 years ago).  You also may want to consider clean or new metal garbage cans as a means to store smaller-size foil-pouched foods.

Pro:

  • Ideal for long term food storage.  The atmosphere within the cans, with the proper sealing, can remain oxygen-free indefinitely.
  • Metal is non-permeable for gas and vapor – a zero transmission rate.
  • Difficult for rodents or animals to penetrate
  • Can withstand some rough handling

Con:

  • Costs can be higher than other materials.
  • Extra attention must be given to proper sealing.
  • Some metal containers may be difficult to obtain.
  • Some cans may rust if exposed to moisture.
Glass jars

Pro:

  • Excellent for long-term food storage.  The atmosphere within the jars, with the proper sealing, can remain oxygen-free indefinitely.
  • Glass is non-permeable for gas and vapor – a zero transmission rate.
  • Difficult for rodents or animals to penetrate.
  • Easily obtainable and relatively inexpensive.

Con:

  • Very fragile – must be stored and handled with care.
  • Practical only in smaller size containers.
Personal Recommendations and Tips for Long-Term, Pack-Your-Own Food Storage

First choice

  • If possible, store foods in metal cans with the proper size oxygen absorber.

Second choice

  • Pack foods in a heavy-duty foil laminate pouch with the proper size oxygen absorber.  I prefer using a variety of smaller size pouches, rather than one large pouch.
  • If you seal the pouch with an iron – as opposed to a commercial impulse sealer – make sure you know the proper method to use.  If your seal isn’t adequate, you are wasting your time and money using an absorber.
  • Place the foil pouches carefully, to avoid “pin holes” and seam damage, into another larger plastic or metal container (NOTE: Sturdy cardboard boxes will do if infestation from insects, rodents, and other animals is of no concern).  This will facilitate handing and storage.
  • When you use the proper size oxygen absorber in a foil pouch, it will create a slight vacuum and the pouch will tighten up somewhat (Remember, you are not creating a complete vacuum that would produce a brick-hard pack; you are only removing about 21% of the air volume.  It will be absorbed by the iron oxide in the oxygen-absorbing sachet).
  • Periodically – especially in the first two weeks – check on the pouch to make sure it still looks tightened up.  If at some point it looks looser, then the integrity of the pouch has been compromised and the atmosphere in the pouch has equalized with the outside atmosphere.

I see no point in putting additional oxygen absorbers into the plastic bucket or container in which the foil pouch is placed.

Third Choice

  • If you have a smaller quantity of dry goods to store and you can protect or store foods safely, use glass jars.  Use either half-gallon size Ball canning jars or one gallon size jars; both need lids with a small rubber seal on the lid to create an air tight container.
  • Drop an appropriate-size oxygen absorber in the jar, then seal it tight.
  • Store away from light.
Additional Tips:
  • I do not recommend using the nitrogen “wand” method of atmosphere replacement in pouches, plastic, or metal containers if you want to create a truly oxygen free environment.
  • The oxygen absorber, properly used, is the best method for creating an oxygen free environment.
  • Certain foods packed for long-term storage may not need an oxygen-free atmosphere.  I have covered the reasons for creating this type of environment earlier, and your specific needs may focus only on containers and storage conditions.
  • I do not recommend storing commodities in their original paper or cloth sacks or boxes for the long term, unless you possess a very secure and unique storage facility.  The important issues here are infestation and environmental influences such as heat, moisture, and other airborne contaminants.
  • Periodically inspect your food reserves for any sign of infestation or contamination.
Storage Conditions

There are six conditions to be aware of when storing food for emergency preparedness food storage or outdoor recreation.  The foods being referred to in this post are shelf-stable, freeze-dried, dehydrated, dried commodities.  Optimal storage conditions can also be applied to wet-pack:  retort, MRE’s, canned goods, and other specialty longer term wet-pack foods.

  • Temperature – This is the primary factor affecting the storage life of foods.  The cooler the better. 40 degrees to 50 degrees F would be great. Room temperature (65 degrees to 72 degrees F) or below is generally fine.  Avoid above 90 degrees F for extended periods of time. The longer food is exposed to very high temperatures, the shorter the edible life and the faster the degeneration of nutritional value.  (NOTE:  There are some “foods” available for emergency preparedness that are known as “emergency food or ration bars.”  These products are generally referred to as “life raft bars” because they were originally designed for life rafts and can withstand high heat for extended periods of time.  They primarily consist of white sugar and white flour, and were not meant to be the sole source of nutrition for a long period of time.)
     
  • Moisture – The lower the better.  Moisture can deteriorate food value rapidly and create conditions that promote the growth of harmful organisms.  The moisture level contained in foods varies depending on the type of product.  Have foods in moisture-barrier containers (metal, glass) in high humidity areas. (NOTE:  Mylar bags or plastic buckets are not a long-term (over 3 years) moisture or oxygen barrier. The moisture and gas transmission rates through these materials vary depending upon the specifications of the manufacturers.  Plastic absorbs gases, moisture, and odors.  Also, be careful where you store dry foods in cans.  Very cold flooring or any condition where there is a dramatic temperature differential may cause a buildup of condensation inside the container.)
     
  • Oxygen – A high-oxygen environment causes oxidation, which leads to discoloration, flavor loss, odors, rancidity, and the breakdown of nutritional value in foods. It also allows insects to feed on dried food reserves. Without oxygen, insects cannot live, nor can aerobic (oxygen dependent) organisms. Whole grain and beans have natural oxygen barriers and can be stored for long periods of time in low humidity if free from infestation. All other processed grains, vegetables, fruits, etc. must be in a very reduced (2% or less) oxygen environment for long term storage.  (NOTE:  Mylar bags or plastic buckets are not a long term (over 3 years) moisture or oxygen barrier. The moisture and gas transmission rates through these materials vary depending upon the specifications of the manufacturers.  Plastic absorbs gases, moisture, and odors.  The best long-term storage containers are glass and metal.)
     
  • Infestation – Examples include rodents, insects in all stages of growth, mold, microorganisms, and any other creatures that get hungry – large or small.  The proper packaging and storage conditions are required to control infestation and not allow critters to get into the food, or prevent the necessary environment for them to flourish if they are sealed into a container, such as in the form of eggs or spores.
     
  • Handling – Rough handling can not only damage the food itself, but it can also adversely affect and compromise the integrity of the container in which the food is stored.  Glass, of course, can break; any pouched item can develop pin holes, tears, or cracks.  The seams on buckets and cans can be tweaked, twisted, or damaged to allow oxygen to enter the container.
     
  • Light – Food should not be stored in direct sunlight, both for the potential of high temperature and its affect on food value.  Sunlight directly on stored foods can destroy nutritional value and hasten the degeneration of food quality, taste, and appearance.  Foods packed in light barrier containers do not pose a problem with the affects of light.

This What Should I Do? blog series is intended to surface knowledge and perspective useful to preparing for a future defined by Peak Oil.  The content is written by PeakProsperity.com readers and is based in their own experiences in putting into practice many of the ideas exchanged on this site.  If there are topics you'd like to see featured here, or if you have interest in contributing a post in a relevant area of your expertise, please indicate so in our What Should I Do? series feedback forum.

If you have not yet seen the other articles in this series, you can find them here:

This series is a companion to this site's free What Should I Do? Guide, which provides guidance from Chris and the PeakProsperity.com staff on specific strategies, products, and services that individuals should consider in their preparations.

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10 Comments

maceves's picture
maceves
Status: Gold Member (Offline)
Joined: Aug 23 2010
Posts: 279
absorbers

Great article!

Any tips on keeping those oxygen absorbers themselves fresh?

Full Moon's picture
Full Moon
Status: Diamond Member (Offline)
Joined: Oct 14 2008
Posts: 1258
canning

our schools are opening their kitchens to teach the public how to can . This is a great community Idea .
FM

jrf29's picture
jrf29
Status: Gold Member (Offline)
Joined: Apr 18 2008
Posts: 445
Important additional information about oxygen absorbers

Oxygen absorbers use iron powder and water (contained in a clay-like substance) which react with oxygen to form rust (iron oxide), thus removing oxygen from the air.  Several key things to remember with oxygen absorbers are:

1). Oxygen Absorbers Add Moisture:  Most research on oxygen absorbers obsessively focuses on their ability to achieve extremely low concentrations of oxygen (~0.1%).  While impressive, moisture is the single most important variable in determining the stability of stored foods.  Small increases in moisture dramatically increase the sensitivity of stored foods to temperature and oxygen.  Conversely, storage temperature and oxygen concentration have far less effect on a product with less moisture. Especially at the low end of the moisture spectrum, small increases in moisture (i.e., from 2% to 3%) result in noticeable decreases in quality and storage life.

Oxygen absorber packages always contain more water than is necessary to complete the chemical reaction.  This excess water evaporates and is sufficient to saturate the air of even larger containers.  See Maekawa, et al.  Therefore, be sure to use an oxygen absorber no larger than necessary.  Also, strongly consider using a dessicant package together with the oxygen abosrber.  Use of a dessicant is always a good idea with dehydrated foods stored in non-hermetically sealed containers.

The lesson: Don't use a larger oxygen abosrber than you need, and consider using a dessicant package.

2).  Oxygen Absorbers Do Not Have Magical Properties: Because the water (as noted above) evaporates, oxygen absorber packages only work for a matter of a few weeks.  While oxygen absorbers may continue to absorb oxygen for months at normal humidity, they will cease working within weeks in the (hopefully) dry atmosphere of dehydrated food storage  Once the water has dissipated, the oxygen absorption stops.  Therefore, if your oxygen absorber is in a location where it cannot be expected to achieve contact with all of the oxygen (i.e., a single packet tossed on the top of a 5-gal. plastic bucket full of potato flakes), then it seems likely that a significant amount of oxygen will be left in the middle and bottom of the container.  The oxygen absorption figures often given (0.1%) represent what an oxygen absorber is chemically capable of achieving in a container with good air circulation.  I would be eager to see research supporting the effectiveness of oxygen absorbers in many of the situations where they are often used by amateur, at-home packers (i.e., a single absorber packet in a 5-gal. bucket of tightly packed food).

The lesson: Several smaller absorbers may be superior to a single larger one for some applications.

3). Freeze-Dried Foods: I would not use oxygen absorbers with most types of porous freeze-dried foods (such as freeze-dried fruits, vegetables, entrees, and meats).  Nor would I buy porous freeze-dried foods that had been packed using only oxygen absorbers, for several reasons:

(a) Freeze dried foods (as opposed to dehydrated foods) have millions of microscopic pores.  Although freeze-drying is the superior preservation technology, these millions of micropores create an enormous amount of surface area on the interior of the foods.  Most of the oxygen trapped in these micropores will never come into contact with the oxygen absorbing material in an oxygen absorbing packet.

For freeze-dried foods, there is much to be said for the nitrogen-compensated vacuum canning process (NOT "nitrogen flushing"), whereby the food is placed into a vacuum chamber, which sucks out almost all of the oxygen from inside of the micropore matrix.  Nitrogen gas is then allowed to flood into the vacuum chamber, which is then sucked deep inside the food particles.

The nitrogen-compensated vacuum process is more than "nitrogen flushing," and while it may result in a final interior oxygen concentration of about 2% (as opposed to 0.1% for oxygen absorbers), the process effectively extracts the oxygen from the deep interior of the food particles and replaces it with dry, inert nitrogen gas.  The small amount of oxygen remaining will not contribute materially to food degradation in the absence of moisture.

These comments apply only to freeze-dried foods, and only to those which formerly had a high moisture concentration and are therefore very porous.  I would be comfortable buying relatively non-porous freeze-dried foods (i.e., biscuits, grains, crackers) preserved with oxygen absorbers.

(b)  Oxygen absorbers will add moisture to freeze-dried foods, defeating one of the biggest advantages of the lyophilization process: the extremely low moisture concentrations achieved.

The lesson:  I am skeptical of the ability of oxygen absorbers to match the benefits of the nitrogen-compensated vacuum canning process (NOT "nitrogen flushing") in the case of freeze-dried foods.  Many cut-rate freeze-dried food manufacturers are cropping up that use oxygen absorbers (because the process is cheap and easy compared to the expensive and heavy equipment needed for a vacuum chamber).  I would keep my distance.

Bottom line:  Oxygen absorbers are great when they are in their niche.  But they are not a panacea and in some circumstances, over-reliance on their abilities or failure to consider their drawbacks can result in a lower-quality stored food product.

Tall's picture
Tall
Status: Gold Member (Offline)
Joined: Feb 18 2010
Posts: 289
Nice overview

Thanks for posting.

Chenopodium's picture
Chenopodium
Status: Member (Offline)
Joined: Aug 30 2008
Posts: 2
Candles?

I have been storing grains and have used candles to get rid of oxygen:

I put a candle in a small glass jar, light it, and close the grain bucket  (I make sure the flame doesn't burn the bucket). The candle burns the oxygen and is automatically extinguished as the oxygen is used up.

Of  course this produces water vapor, so I have also included silica gel water absorbers (that turn color from orange to white when saturated, so that I know if I have added enough).

Is there any reason *not* to use candles?

Seems cheap and easy to use to me... (I have used oxygen absorbers too, but have never been quite sure if I did it right... with the candle I can actually see that the oxygen is used :-).

jrf29's picture
jrf29
Status: Gold Member (Offline)
Joined: Apr 18 2008
Posts: 445
Use of candles to remove oxygen

chenopodium wrote:
Is there any reason not to use candles?

There is one reason: they don't remove very much oxygen.

Normal air contains about 21% oxygen.  A burning candle or other fire in a closed container will go out once the oxygen concentration has dropped to about 17% (actually still enough for a human to breathe).  While better than nothing, the candle also adds moisture to the air.

Combustion in a closed container at sea level can theoretically continue until oxygen concentration drops to 16%.  In practice, a candle will leave between 16%-18% oxygen, and 3% carbon dioxide.  Wang, et al., pg. 292.

So, a candle won't make a big difference in terms of oxygen reduction, especially considering that more oxygen will penetrate through the walls of plastic buckets over a period of months.  The advantages are probably counterbalanced by the smoke and water vapor.

In your particular case, your real friend is probably the silica gel that you've been adding.  Silica gel will keep working indefinitely to absorb moisture that seeps into a plastic container (until the silica is saturated).  Lower moisture levels are preservative in themselves, and will also greatly reduce the food's sensitivity to oxygen and heat.

DenisKorn's picture
DenisKorn
Status: Member (Offline)
Joined: Nov 3 2011
Posts: 11
Using Oxygen Absorbers

Hello maceves.  Since I wrote this article and have extensive experience using oxygen absorbers, I highly recommend you read my article on using oxygen absorbers - http://learntoprepare.com/using-about-oxygen-absorbers/ at my blog LearnToPrepare.com.  For your information, I was the person who first utilized oxygen absorbers in the preparedness industry in the early 1990's as a canner of preparedness foods and backpacking meals at AlpineAire Foods - the company that I owned at that time.  Feel free to contact me if I can be of futher help.

maceves's picture
maceves
Status: Gold Member (Offline)
Joined: Aug 23 2010
Posts: 279
thanks

Thank you.

So the extra ones that I put in a jar last summer aren't good any more?

Billy Gamble's picture
Billy Gamble
Status: Member (Offline)
Joined: Jun 6 2013
Posts: 2
Packaging Supplies

Packaging is really important if you want to make a sale 

michaelmaloney's picture
michaelmaloney
Status: Member (Offline)
Joined: Sep 29 2014
Posts: 4
Food storage should be

Food storage should be encouraged even if you do not live in a disaster-prone area or experience seasonal changes like winter. Food storage can be useful for other purposes as well like unexpected chronic illness, disability or even loss of job. When we store food, we can at least prepare ourselves for the least expected situations and still have food for a few months in the running. However, if not done up properly, then the food might go to waste before its expected shelf life.

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