When I first heard someone mention oxygen absorbers in casual conversation, I thought “What are those, again?” But as soon as I saw a picture of them, I knew exactly what they were.
You’ve most likely seen these little packets in packages of food that you purchase at the grocery store. They’re usually white, but can come in other colors as well.
The reason I first became interested in these was because they came up in my research, when I was exploring ways to preserve food that I had dried with my food dehydrator. I wanted my food to last throughout the year and stay crisp.
Once I started reading about them, I knew these were exactly what I was looking for.
Today, I want to share what I’ve learned with you, regarding how they work, and some ways you can start using them in your own kitchen with your home dehydrating pursuits.
The best part is, they’re easy to use (and super inexpensive, too)!
So, What Are They?
These little parcels are filled with iron powder. The iron absorbs 99% of the oxygen that’s present when placed in a sealed environment, like a jar or bag. The remaining atmospheric gases are completely inert and don’t lead to food degradation through the oxidization process.
When the packets are removed from their sealed container, they immediately start absorbing O2, which reacts to with the iron powder, forming iron oxide through a catalyst.
If the packets are placed in a sealed environment such as a canning jar or bag, almost all of the oxygen will be removed (if you’ve used the correct quantity of packets), and the chemical reaction will stop.
The remaining atmospheric gases – mostly nitrogen – is ideal for long-term storage. This keeps food from going rancid, and also keeping bugs and insects out.
The moisture and air are absorbed, but the powder inside the packet is kept secure and separate from edible items. This means you can place the packets directly on your food in the appropriate container, without having to worry about these items becoming contaminated.
When oxygen absorbers are in use, they heat up – if you were to remove one that’s activated from your jar or container of dry goods while it’s doing it’s thing, it would actually be warm to the touch. They work on the same chemical reaction process as disposable hand warmers.
They generally take up to four hours to remove the O2 from a sealed bag or other container.
Why Use Them?
There are a few reasons why you might want to use these.
The main reason is that, if you’re interested in dehydrating your food at home, they will increase the shelf life of these products. Or, if you buy any food that’s already been dried, they can be used to further extend the life of these items as well.
One thing I really like is that they preserve food without using any artificial additives or chemicals to make the food last – which is the route a lot of pre-packaged food companies take.
They also help to keep pathogens from growing in your food. Many unwanted organisms and various types of mold cannot survive in an environment that is all nitrogen.
If you keep the oxygen out, your food will be safe, and it will keep for the long haul. If not, it runs the risk of spoiling.
An important note:
O2 absorbers should never be used to preserve products that contain more than 10 percent moisture, as this type of packaging may increase the risk of botulism poisoning.
Products with a high oil content (like nuts, seeds, and whole grains) will have a shorter shelf life than other products. If you are uncertain as to which specific items may be preserved with these products, I encourage you to do further research.
Now, there’s no denying that these are easy to use. But to make sure they do their job effectively, there are a few things you need to be aware of beforehand:
When using these, many people go wrong by opening them up too soon, and failing to get them into a sealed container quickly enough. The problem involved here is that they start working immediately.
If you open them before your food is ready to store, the packets will start absorbing the air, and won’t have much iron left to preserve your food.
Another problem you might face when preserving your food with these packets is trying to use ones that no longer work.
How can you tell?
A lot of companies will include a little pill in the container. If it’s pink, then they’re still good. If it’s blue or purple, they’re no longer active, and should be tossed.
It’s important to keep in mind that some companies claim the pill will still be pink if only one packet in the entire package is good. In other words, in a package of 100, 99 could be bad if just one is still good, and the pill will still be pink.
That being said, another way to check is to simply hold the packet in your hand. If you can feel the loose powder, that’s a good sign that it’s ready to use. If it’s hard or solid, that usually means the contents have been used up already, and you should dispose of it.
Keeping that in mind, be diligent when storing extra absorbers – the better you are able to preserve them, the less frequently you will have to buy more to replace ones that have expired. This is better for your wallet, and the environment.
Using Oxygen Absorbers
1. Determine exactly how many packets you’ll need to place in with your food.
2. Prepare your food by placing it in the container you wish to store it in.
3. Have a container ready to store the remaining packets in. Once you open the bag, you’ll need to place the leftovers in a container that is properly sealed right away.
You can always reseal the bag you bought them in with a hot iron. However, you won’t be able to do that more than a few times, as it will become hard to open and then reseal if the bag gets too small.
4. Be prepared to seal your container as soon as you place the packet(s) inside.
5. Store in a dark, dry place.
Recommended Containers for Storing Your Food
When it comes to containers, the best for this job are Mylar bags, Mason jars, and large buckets. All three of these seal very well, making them perfect options.
The amount of food you are preserving will help you to figure out what type of bag you’ll want to use. If you are preserving a small amount, a Mason jar should do the trick.
If this is the case, simply place the food in the jar with the packet(s), then use the ring and lid to seal the can.
Gallon Mylar Bags with 500cc Oxygen Absorbers available on Amazon
The absorber will do the sealing part, by removing the air. You will hear a pop when it’s done, and you shouldn’t be able to make the top move when you press down on the lid.
If you’re storing a greater quantity of food, a Mylar bag or a food-safe bucket might make more sense.
Place the food in the bag, leaving some room at the top. Fold the bag closed, and then seal it.
To create a seal, you’ll need to run something hot over it to completely close it – a clothing iron or an electric hair straightener both work well.
From there, if you wish, you can place the bag in a bucket with a lid for extra protection.
Vacuum sealers seem to work okay as well. Personally, I prefer the Mylar bags, but many people swear by these.
Simply add the recommended number of packets, and then use the sealer to close the bag.
How Many Packets Will You Need?
In order to know how many packets are needed, you’ll have to figure out how much oxygen your container holds. To do this, you need to determine the volume.
In addition to the volume of the container, you’ll also need to consider the type of food that’s being packed.
Finally, you will need to figure out the volume of the “void space” (the empty space between the food items) and the “head space” (all of the space in the container that’s not filled).
To help you get started, here’s a general formula to find the oxygen absorption required, in cubic centimeters:
Container Volume – Food Volume = Residual Air Volume
1 gram (g) = 1 cubic centimeter (cc)
It’s hard to estimate void space and head space, so I recommend adding a few extra cubic centimeters. It’s better to be on the conservative side where food safety is concerned.
Usually Sold in the Following Sizes:
Now, if you’re not good with math, here are some popular storage container sizes and the size packet you will need:
- 1 pint up to 1 quart Mason jar = 50cc
- 1 gallon Mylar bag = 300cc
- 5 gallon bucket with low air volume (think rice and flour) = 1000cc
- 5 gallon bucket with high air volume (think pasta) = 2000cc
Depending on what size you choose to purchase, you can always combine packets to reach the total quantity of cubic centimeters of volume that you’re working with.
When it comes to using this product, consider the many dried foods you commonly store and that you don’t want to go bad. These may include staple items such as:
- Seeds (unless you plan to sprout them)
- Dried Fruit
- Dried Vegetables
- Popcorn Kernels
There are just two things you’ll want to completely avoid adding these packets to: sugar and salt.
Neither one needs to be preserved. If you think about it, salt and sugar are often the substances that are actually used to do the food preservation – so extra preservatives aren’t needed!
If you use these packets in a container filled with sugar or salt, you can expect them to turn rock solid, becoming totally useless to you.
Not to Be Confused with Silica Packets
It’s easy to mistake the product that I’m talking about with silica gel, which is made of silicon dioxide.
You’ve most likely seen silica packets in with your new shoes, purses, or electronic products like cameras.
Silica packets are desiccants, meaning they help to remove moisture and keep things from molding.
According to All Things Emergency Prepared, it’s important to be sure that desiccants are properly packaged before using them with food, because they are not edible. If the desiccant accidentally opens and mixes with your food, you must throw it all away.
If you’ll be using oxygen absorbers and dessicants together, it’s best to place the silica packets on the bottom of your chosen storage container, and the oxygen absorbers on top.
Additional Food Storage Tips
Check out the following tips, to help get you started on the road to successful food storage using oxygen absorber packets.
When storing food, it’s important to keep the temperature at or below room temperature. I suggest keeping things at 40-50°F, if you can manage it.
However, typical room temperature is usually much warmer. Storing dry goods at temperatures below 75°F and away from direct sunlight is usually fine.
You’ll want to avoid temps over 90°F entirely, as this kind of heat will speed up the arrival of that expiration date.
Watch for Moisture
If you store your food in a cold or moist environment, condensation is likely. And this will cause your food to spoil at a quicker rate. That being said, you want to store it in as dry of a location as possible.
Foods high in moisture or oil, even if they seem “dry,” are not ideal candidates for preservation with oxygen absorbers. Storing these foods in this type of packaging increases the risk of botulism.
According to Carolyn Washington, FCS agent and associate professor in the food and nutrition department at the Utah State University Cooperative Extension, some foods are not actually sensitive to oxygen, so there is no use in utilizing O2 absorbers to store them.
These include: beans, peas, corn, and wheat.
Look Out for Light
Sunshine is the number one culprit here. This is why I don’t recommend storing your product on a counter, or out in the open.
A cabinet that is dark and dry is going to be your best bet. The basement is fine as long as it’s not too cold, and if you keep your food up off the ground.
300cc oxygen absorbers available on Amazon
If you follow these tips in combination with using the right quantity of active packets, your food should keep very well.
I hope this post has cleared up any questions you may have. Get out there and give this product a try, and use what you’ve learned here to improve your food storing efforts. Let me know how it goes in the comments!
Photos of absorbers in use by Mike Quinn, © Ask the Experts, LLC. ALL RIGHTS RESERVED. Product photos are owned by their respective manufacturers and/or distributors. See our TOS for more details.
Foodal and Ask the Experts, LLC are not liable for any use or misuse of the products described within this article; do your own due diligence to learn the appropriate guidelines for storing food. Observe guidance and best practice recommendations issued by the U.S. Food and Drug Administration (or your country’s equivalent) and state and local organizations (such as university extensions), and take all necessary precautions to safely store your perishables.
About Sarah Hagstrom
Sarah is a health food advocate and loves to spend her time whipping up something healthy and delicious in the kitchen and then sharing either on Foodal or on her own blog "The Seasonal Diet" (www.theseasonaldiet.com). She lives in Sunny San Diego with her husband, where they enjoy running on the beach and weekend adventures.