When I first started seriously looking into food storage back in the day, I had no clue how to use oxygen absorbers. I just knew they were really helpful, especially for someone like me that always has so much food to store.
Before I learned a little about them, I had serious problems with food degradation.
Thankfully, a friend taught me about the oxygen absorbers for food storage that help you maintain your food’s original flavor, color, and nutritional value. They can also prevent oxidation in vitamins and medicines which means a longer shelf-life.
So, as I learned more about storing food, I quickly learned that using oxygen absorbers to package dry foods you buy in bulk is an inexpensive way to begin basic food storage. But, in order to do so safely, you must know how to use oxygen absorbers the right way.
Below are the basics you need to know about using oxygen absorbers.
Everything You Need to Know About Oxygen Absorbers
I have taught classes on food storage for various groups and have realized that there are some misunderstandings regarding how to use oxygen absorbers safely.
So, I want to be certain that those who choose to follow and trust me to have the information they need. The last thing I want is for my readers to use oxygen absorbers in a way that won’t safely preserve their food.
So let’s jump right in!
1. What are oxygen absorbers?
Oxygen absorbers are harmless little packages of iron powder. They are non-toxic and BPA-free.
They are also used to remove oxygen from the air (which is 21% oxygen, with the rest being mostly nitrogen) when packaging dry foods.
So, when you put an oxygen absorber in an airtight container, the oxygen in that container “sticks” to the iron in the oxygen absorber. This leaves only nitrogen in the air (which doesn’t affect your food). Check out our article about food storage comparison to help you decide next time.
2. Why should I use them?
First of all, an important part of knowing how to use oxygen absorbers safely is knowing why they are used at.
So, there are five main reasons to use oxygen absorbers when packaging dry foods:
- To increase shelf life (up to 30 years for most dry foods).
- Secondly, to prevent mold or bacteria growth in your food. Nothing will grow without oxygen to feed on! Especially when your food is dehydrated or freeze-dried.
- To preserve vitamins such as A, C, and E that are depleted when exposed to oxygen.
- To prevent dehydrated or freeze-dried fruits from browning
- So that flavor will be kept.
- Last but not least, to kill pest eggs that may be found (but too small to see) in your food (usually grains). These eggs cannot hatch/multiply without oxygen.
Most dry foods have a decent shelf life (one to five years), all on their own without an oxygen absorber. So if you plan to rotate through your foods regularly, you don’t necessarily have to use an oxygen absorber. However, if you choose to (and they are quite inexpensive), you gain the above benefits.
Tip: You can also kill pest eggs by putting your food in the freezer for 48 hours.
3. Where can I buy it?
There are many places to buy oxygen absorbers online, but I get mine on Amazon. You can sometimes find them at Walmart but I have noticed not all stores carry them.
4. What type of containers can I use?
Oxygen absorbers are most effective when used in airtight containers.
But these other types of containers should work too if you adjust for the issues that they each have.
1. Foil pouches (often called Mylar Bags)
Mylar bags should be at least 5 ml to adequately protect your food from light, oxygen, and moisture. However, even at 5-7 ml, they are easy to puncture and not even close to rodent-proof. Therefore, they should be used inside of a food-grade bucket or in another rodent-proof container. Two good places to get mylar bags are Discount Mylar Bags and Mylar Bags Direct.
2. Mason jars
Mason jars keep food dry and fresh, can’t be punctured, and are rodent-proof. However, they are not very earthquake (or child/pet) proof as they can shatter. They also do not keep light out, so they would need to be stored away from light.
3. Metal cans with seamed lids (typically #10 cans)
A #10 can keep oxygen and moisture out, cannot be punctured, and is rodent, earthquake (as much as possible), child, and pet-proof. In addition, when I open them, I only have 11-12 cups of food to get through before it expires, as opposed to 90+ cups in a 5-gallon bucket.
But, you have to have special equipment to seal them. This equipment is extremely expensive. I used to be able to rent the equipment from LDS Home storage centers, but they are phasing that out.
4. Food-grade plastic buckets (typically 5-6 gallons) with mylar bags
Plastic buckets are tough to puncture, and rodents, earthquake (as much as possible), child, and pet-proof. However, plastic buckets do not keep oxygen and moisture out as well as the rest of the options do.
As a result, you will want to use them in combination with mylar bags.
In addition, since you will likely need to get into/out of your bucket many times (once opened) to get through all that food, I suggest using them with a gamma lid. Gamma lids seal out oxygen but can be screwed on and off.
Each time you open your bucket, simply check your oxygen absorber to see if it is hard. If it is, it will not absorb any more oxygen. When it is hard, remove the oxygen absorber and throw a new one in before screwing the lid back on.
Note: You can find some airtight plastic PETE containers, but most commonly used HDPE 5-gallon buckets are not completely airtight and will continue to let oxygen through (though in small amounts).
5. Containers not to use
Do not use zip-seal plastic bags or non-PETE plastic containers without a mylar bag.
What types of food can I store with it?
When learning how to use oxygen absorbers, I believe this is the most important thing to consider.
First of all, you can only use oxygen absorbers on DRY foods (10% moisture or less). If you package moist foods using an oxygen absorber, you run the risk of botulism. You should also avoid oily foods.
Dry foods that the LDS church recommends NOT be stored with an oxygen absorber are:
- Brown Rice
- Pearled Barley
- Dried eggs
- Milled grains (other than rolled oats)
- Brown sugar
- Any dehydrated fruit or vegetable not dry enough to snap when bent
Now, you will find varying opinions on this. Some websites recommend storing many of the above ingredients with an oxygen absorber.
Also, there are many “preppers” who will tell you that they’ve stored the above items with no issues – and I don’t doubt that they have.
When I say that you run a risk of botulism, I don’t mean that you will get botulism. In fact, it would be rare. But for me personally, I tend to be very cautious when it comes to my family’s health and the food I spend my money on.
So, I just don’t want to waste that food by packaging it incorrectly as a result, it will kill your food. You wouldn’t want that to happen.
Also, I trust the LDS church as a solid reference when it comes to food storage. They have been recommending food storage to their members for a long, long time, and I trust their research is accurate.
In addition, other foods should not be packaged with oxygen absorbers:
- Leavening agents (baking soda/baking powder) as cans may explode
- Salt/Sugar (they have a forever shelf life without the oxygen absorber and turn very hard with an oxygen absorber)
How Many Oxygen Absorbers Do I Need?
It is very hard to know exactly how large or how many oxygen absorbers you will need. It will vary depending on the container size, how much open space you leave at the top of a container, as well as the density of the food you are packaging.
While you don’t want to waste money using too many oxygen absorbers, it is better to use too many (or one that is a little too large) than too little.
A little extra won’t hurt your food. But, if you use too few or one that is too small, there will still be oxygen packaged with your food. So, you may not kill all pest eggs and/or bacteria, and you may lose more flavor and vitamins.
As a general rule for usage (erring on the side of too much instead of too little):
- For quart containers or smaller, a 100cc oxygen absorber should work.
- Secondly, for containers larger than a quart and up to 1 gallon, a 400 cc absorber should work.
- For containers larger than a gallon and up to 5 gallons, 400 cc’s per gallon should work.
- For 5-6 gallon buckets, a 3000 cc should work.
You can also download the following oxygen absorbers chart, which will tell you how many products will fit in various containers and how many oxygen absorbers to use.
What are the actual steps for using these products?
Step 1: Prepare your containers
Make sure the containers you plan to use are clean and completely dry. Also, make sure the lid is nearby so you can quickly seal the container once you add the food and oxygen absorber.
Step 2: Prepare your food
Make sure your food is free of any debris (common with beans). Then add it to the containers you’ve decided to store it in, but do not put the lid on yet.
Step 3: Set aside a mason jar with lid
This is an optional step, but I find it helpful!
Oxygen absorbers will begin to soak up oxygen immediately when removed from the packaging. A tip that can help is to store any absorbers you aren’t currently using in a tightly sealed mason jar.
Step 4: Open your package
Pull out one oxygen absorber and seal the rest in your mason jar. Add one oxygen absorber to your first container.
Tip #1 – Oxygen absorbers should feel like they have something soft and powdery inside. If you have one that feels hard or chunky, it has already absorbed all the oxygen it is going to absorb–chuck it.
Tip #2 – Oxygen absorbers will heat up as they start to absorb oxygen. So if you are handling one that is warm, that is a good sign it is working. Just seal it up asap! If it gets hot, I would toss it.
Step 5: Seal your container
If you are storing your food in a mylar bag, here is a great video of how to seal them well (hoping to make one of my own soon, but for now, Prep Charley does a great job!)
Step 6: Label
Label your food and be sure you include what is in the container, as well as the date you packaged it.
Step 7: Wait, then check
It can take up to a few days (even a week) for the oxygen absorber to remove all the oxygen in the container.
If you are using cans or jars, everything should be fine. But if you are using mylar bags, you will want to check that your seal is good.
Remember that oxygen absorbers use up oxygen, not air. Air is only 21%(ish) oxygen. This means that nearly 80% of the air will still remain. So, your packages may not look like they’ve been vacuum sealed.
But, there should be a slight reduction in the residual amount of air in the bag (and if you forced as much air out as possible before you sealed it, the package might look vacuum-sealed).
Last but not least, if you do not see at least a slight reduction in the amount of air in the bag, open it, add another oxygen absorber and re-seal it.
Step 8: Repeat
Repeat steps 4-5 for each container you are preparing.
Step 9: Re-seal your product
This step is important because if your oxygen absorbers go bad it won’t matter if you know how to use oxygen absorbers or not!
So, make sure to store your leftover oxygen absorbers in an airtight mason jar. They should last six months to one year. Be sure you check them again before you use them (if they are hard or chunky, toss them out).
Are oxygen absorbers and FoodSaver the same thing?
Many people assume that oxygen absorbers and a FoodSaver do the same thing.
It is important to know the difference when learning how to use oxygen absorbers.
Oxygen absorbers remove oxygen. In fact, they remove essentially ALL oxygen (99.99%) that is required for long-term storage of foods (0.01-0.02 % oxygen left is the safe range).
It’s so-called “substitute” removes air (oxygen, nitrogen, and a little of other things) through a vacuum. It does not remove ALL oxygen.
However, this does NOT mean that the FoodSaver is useless. In fact, it has a lot of benefits. For example, remember those items that can’t be stored in an oxygen-free environment (those with high moisture or oil content)? Well, those items CAN be stored using this kind of product!
And while you won’t get a 30+ year shelf life out of them, you will increase the shelf life by about three-five times.
Using oxygen absorbers vs. Using Silica gel/desiccants?
When I first started working on my food storage, even the term “oxygen absorber” was completely new to me. So, I had no idea that there was another similar little package you could add to your food called a Silica Gel Packet or a desiccant.
Now I know that there are two little packets that do very different things. Unfortunately, many people (like me a few years ago) don’t realize this.
Here is the difference:
- Oxygen absorbers remove oxygen.
- Silica Gel packets/desiccants remove moisture.
However, you can’t use a Silica gel packet to remove enough moisture to safely package moist foods (see list above) with an oxygen absorber.
My favorite use for Silica gel packets is in opened #10 cans of freeze-dried food. Freeze-dried food has had nearly all the moisture removed, and as it sits in an opened #10 can, it will start to absorb moisture from the air.
This changes the texture and can shorten the open shelf life. But throw a few 10-gram packages in the can, and you’ll fix the problem. Just make sure you replace them every few weeks (or more often if you live in a very humid environment).
Silica Gel Packs are also often used to keep ammunition and firearms, silver, tools, and important documents dry as well. They can also be used to dry up a wet cell phone!