If exposed to oxygen, even non perishables like beans and rice will eventually start to go bad. If you want to store food long-term, you’ll have to protect it from oxygen. Luckily, there’s a cheap and easy solution: oxygen absorber packets.
What Are Oxygen Absorbers?
Oxygen absorbers are little packages containing iron. When you put the oxygen absorber (OA) into an airtight container, the oxygen molecules “stick” to the iron. OAs can reduce the amount of oxygen in a container to less than 0.01%. (1)
Keep in mind that air is about 78% nitrogen, 21% oxygen, and about 1% other gases. Oxygen absorbers only remove the oxygen. However, nitrogen does not cause food to spoil.
Benefits to Using Oxygen Absorbers:
- Keeps food from degrading due to oxidation
- Prevent mold and bacteria from growing on the food (mold and most bacteria* require oxygen to grow)
- Preserve flavor
- Prevent vitamins from being destroyed by oxidation
- Kill pests (tiny pest eggs which are invisible to the eye may be on your food; without oxygen they cannot hatch)
*See the section on botulism in the FAQs
How to Store Food with Oxygen Absorbers
To store food with oxygen absorbers, you will need to put the food and oxygen absorbers in an air-tight container. If the container leaks air, then it is pointless to use oxygen absorbers. There are four main containers which can be used for long-term food storage with oxygen absorbers.
1. Mylar Bags
Mylar is a metallic-looking material which doesn’t allow air or humidity through. Mylar bags are very cheap and durable, which makes it one of the best long-term storage packages for dry food.
To store food in it, you will fill up the Mylar bags with dry foods, add oxygen absorbers, and then seal the bags. You can then put the Mylar bags in buckets with lids. This will keep food safe against virtually any disaster. Some people even do “Mylar bag parties” with friends so they can seal a lot of food in one go.
- Protects against light
- Virtually indestructible when bags are put into buckets
- Cheapest long-term storage option
- Bags come in many sizes
- Slight learning curve
- Cannot see food inside bag
For detailed instructions, see our post on mylar bags for food storage.
2. Canning Jars
For storing smaller amounts of food long-term, you can put the food in canning jars or Mason jars (jars with a two-part lid). Just add the right amount of oxygen absorber to the jar and then screw on the lid. You’ll know the oxygen absorbers are doing their job because the jar lid will get sucked down.
Other jars can also be used with oxygen absorbers. However, the lids on these jars are much more likely to leak. To play it safe, it’s best to stick to canning jars.
- Very easy
- Easy to rotate food
- Jars are breakable
- Only hold small amounts of food
- Don’t protect against light
The simplest way to use oxygen absorbers with large amounts of food is to put them into food-grade buckets. You fill up the bucket with dry foods, add the right amount of oxygen absorbers, and then close the lid.
The downside is that most buckets will leak air inside. This includes the cheap HDPE 5 gallon food-grade buckets. They slowly leak air, so you could still use them with oxygen absorbers – just not for long-term storage. You are much better off with a gamma-seal lid bucket. These buckets cost more but actually do create a tight seal.
Also note once you open the bucket, you will expose the food to air. If you want to reseal the bucket, you’ll have to add more oxygen absorbers.
So, this method isn’t good if you plan on rotating through your food stockpile. Personally, I’d only recommend using buckets as a short-term solution until you are able to get enough food stockpiled to have a “Mylar bag party.”
- Can easily store large amounts of food
- Buckets are durable
- Most buckets leak air through lid
- Will expose food to oxygen each time you open the bucket
- Gamma lids are a bit pricey
4. #10 Cans
A lot of emergency foods – like butter powder from Augason Farms or Mountain House’s scrambled eggs – are packaged in #10 cans (pronounced ten pound cans). If you get a can sealer, it’s possible to store your own food in these cans at home too.
Using #10 cans for food storage is actually pretty simple. You just put your dry food in the cans, add oxygen absorbers, and seal the can. The seal is completely air-tight and the cans are tough enough to withstand almost any disaster.
The downside is that the cans and the sealer are pretty expensive. If you are lucky enough to know someone who already has a can sealer which you can borrow, then you only have to worry about the costs of the cans.
- Disaster-proof packaging
- Protects against light and physical damage
- Smaller quantities of food per can make use and rotating easier
- Cans and sealer are expensive
- Only can store small amounts of food per can
How Many Oxygen Absorbers To Use?
Oxygen is in the food container in two places:
- In the space between the food
- Inside the actual food
If you want to keep the food safe for long-term storage, you’ll need to remove virtually ALL of this oxygen. This means making sure you use enough OAs.
Below is a general guideline of how many oxygen absorbers you will need. However, the amount can vary depending on things like whether your batch of beans is uniform in size (lots of air space between the beans) or varying in size (less space between the beans).
If you really want to know exactly how many OAs you need, you’ll need to do some math. I’ve included the math in the dropdown for those who are interested.
|Food Type||1 quart||1 gallon||5 gallon|
|Beans, lentils, split peas||125-150cc||500-600cc||2500-3000cc|
|Instant mixes and powders||100cc||400cc||2000cc|
|Whole grains (barley, corn, wheat, oats)||125cc||625cc||2500cc|
It is always best to play it safe – use more oxygen absorbers than you think you need! Using extra oxygen absorbers won’t impact the food. OAs are cheap, better to spend an extra 25 cents on an additional oxygen absorber than throw away 5 gallons of food when it’s needed most.
What Foods Can Be Stored with Oxygen Absorbers?
Just about any dry and low fat food can be stored with oxygen absorbers. This includes foods like:
- Whole grains
- Dried beans
- Powdered milk
- Freeze-dried food
Note: Not all foods are oxygen sensitive. For example, whole grains, peas, and beans aren’t too sensitive to oxygen. If you plan on using the foods within 5 years, there won’t be too much difference in freshness regardless of whether you use an OA or not.
However, oxygen absorbers do protect against pests and have other benefits like preserving nutrition. Since OAs are pretty cheap, I recommend using them with all dry foods you want to store for 12+ months.
Dehydrated Food with Oxygen Absorbers
Most home dehydrated fruits and veggies usually aren’t suitable for long-term storage. They simply contain too much moisture. If the moisture level is too high, you could even risk botulism poisoning (more on that below).
To safely store dehydrated food with OAs, the food must be so dry that it snaps when bent. Or, for round foods like corn or peas, it should shatter when pressed with a spoon.
Nuts and Seeds with Oxygen Absorbers
Storing nuts and seeds with oxygen absorbers will extend their shelf life. However, because they contain so much oil, they will eventually start to go rancid.
Most people put the shelf life of nuts/seeds with OAs at about 2 years. However, nuts and seeds can last longer than this even when exposed to oxygen. The key is keeping the temperature and humidity low.
*Granola also has a lot of oil in it and won’t store long-term.
Foods which Should NOT Be Stored with Oxygen Absorbers
- Salt: Will become rock hard if stored with an OA
- Sugar: Also will become rock hard; brown sugar also contains too much moisture for storage with OAs. Read how to store sugar for the long term.
- Wet foods: Foods with moisture of 35% or more can grow botulism in airless environments. To play it safe, it is recommended that foods stored with OAs have 10% or less moisture.
- Baking soda, baking powder, pancake mixes, and yeast: There’s some debate about whether OA can be used with these foods. Some claim that a chemical reaction could occur and result in the leavening products then become useless.
Botulism is usually only talked about in regards to home canning. However, because the botulism bacteria grows in no/low oxygen environments, it could also grow in Mylar bags packaged with oxygen absorbers.
Botulism requires moisture of 35% to grow. However, to play it safe, virtually all food preservation guides will say that food must have 10% or less moisture to be packaged in airtight containers with oxygen absorbers. (2)
This shouldn’t scare you away from self-storing foods with oxygen absorbers. Just make sure you aren’t storing any moist foods in sealed containers with oxygen absorbers.
The good news is that botulism toxin (which causes the disease) can be easily destroyed by boiling for 10 minutes. The CDC states, “Despite its extreme potency, botulinum toxin is easily destroyed. Heating to an internal temperature of 85°C for at least 5 minutes will decontaminate affected food or drink.” This page also has good info on deactivating botulism. Many of the foods which get stored for long-term need to be boiled anyway (dry beans, dry grains, etc.), so this in theory would kill any contaminants.
However, that doesn’t mean you should eat any foods which you suspect are contaminated with botulism.
Warning: If the package is bulging (a sign that bacteria or toxins are growing inside), then don’t eat its contents!
Shelf Life of Foods with Oxygen Absorbers
Remember that OAs only protect against oxygen. You’ll also want to protect your food against heat, light, and physical damage.
The following table gives you general guideline of what shelf life you can expect when packaging food with oxygen absorbers.
|Hard Whole Grains |
(Dry corn, buckwheat, soft white wheat, durum wheat, spelt)
|Soft Whole Grains (Oats, quinoa, rye, barley)||8+ years|
|Professionally-Dehydrated Vegetables||10-20 years|
|Professionally-Dehydrated Fruits*||10-15 years|
|Home-Dehydrated Fruits and Veggies*||2-5 years|
|Freeze-Dried Fruits and Vegetables||25 years|
|Legumes (Beans, lentils, chickpeas, split peas)||25+ years|
|White Rice||10-30 years|
|Brown Rice||2-5 years|
|White Flour||10-15 years|
|Whole-Wheat Flour||10 years|
|Corn Meal||5-10 years|
|Potato Flakes||30 years|
|Dry Non-Fat Milk||15 years|
|Cheese Powder||10-15 years|
|Powdered Eggs||5-10 years|
*Dehydrated fruits and vegetables must have less than 10% moisture to be safely stored with OAs. They will snap when bent or (with round food like corn) shatter when pressed with the back of a spoon.
How to Store Unused Oxygen Absorbers
The moment you take oxygen absorbers out of the package, they will start to absorb oxygen. After around 2-4 hours, they’ll have absorbed their maximum capacity of oxygen.
It is important that you have a plan on what to do with any unused oxygen absorbers before you begin working. Ideally, you will reseal oxygen absorbers in the packaging they came in. Then you vacuum seal them.
If this isn’t an option, you can also store unused oxygen absorbers in a mason jar. Fill up any extra space in the jar with marbles (or something similar). The less air that is in the jars, the less air the unused OAs will absorb. Be sure to seal the jar tightly!
How to Tell If Your Oxygen Absorbers Are Still Good
If you buy OAs from a reputable company, they should be good. We like the supplier DiscountMylarBags, they are the cheapest around and provide good quality products. They also sell on Amazon if you prefer to shop there)
They will arrive in a vacuum-sealed package. Most oxygen absorbers have a “margin for error” added into their abilities (DiscountMylarBags use ShieldPro absorbers they absorb 200 to 300% of their rating). So, they will actually absorb more than specified.
This is so you can have a good 10-20 minutes to work with the OAs and not have that air exposure count against you.
Here’s how you can check:
- They arrive in a vacuum-sealed package.
- The oxygen indicator is pink or red and not blue.
- The packets feel soft and not crunchy.
Oxygen Absorbers vs. Desiccants
Oxygen absorbers will absorb oxygen. Desiccants will absorb moisture. OAs actually require a small amount of moisture for them to activate. Thus, it’s generally not recommended to use both OAs and desiccants together.
There are some exceptions to this rule though. Some foods (like home-dehydrated fruits) may contain a lot of moisture. Since moisture is one of the things which makes food spoil, adding a desiccant can help the food last longer.
In this case, it’s best to use silica gel desiccants because they don’t absorb so much moisture that it will interfere with the OA. Some more advanced types of desiccants can reduce the moisture to practically zero, which means they would stop the OAs from doing their job.
*When using both oxygen absorbers and desiccants, put the desiccant on the bottom of the package and the OA on the top.
Oxygen Absorbers vs. Vacuum Sealing
Oxygen absorbers and vacuum sealing both work by removing air from packaging. However, vacuum sealing doesn’t remove all the oxygen like OAs do. Also, the vacuum seal bags are actually not air-tight and will slowly leak air into the package over time. Thus, vacuum sealing is NOT suitable for long-term food storage.
There’s also no reason use oxygen absorbers and vacuum sealing together: OAs do their job well enough without any need to first suck out air. Further, the vacuum sealer will remove nitrogen from the packaging (oxygen absorbers only remove oxygen). If you add an OA to a vacuum-sealed bag, the bag may get so “sucked in” that sharp edges on foods like rice could tear through the bag.
This doesn’t mean that vacuum-sealing isn’t good for food storage. Vacuum-sealing can increase shelf life of foods by 3-5 times. It’s also great for storing foods which aren’t suitable for OAs, such as moist foods. But, when it is long-term storage that you want (5+ years), then sealed containers with oxygen absorbers is the way to go.
Oxygen Absorbers vs. Gas Purging/Nitrogen Flushing
I’ve recently come across many guides and videos about gas purging (aka nitrogen flushing) Mylar bags. The basic idea is that you use a special machine to force nitrogen gas into the package. The nitrogen flushes out any oxygen. Then you seal the package so only nitrogen remains.
Nitrogen flushing is used by some food manufacturers to keep their greasy foods (such as chips) fresh for a long time. That’s why bags of chips are puffy when you get them.
However, unless you have access to professional equipment, nitrogen flushing is very difficult to do! You have to displace all of the oxygen and make sure none gets back into the bag before you seal it.
Packaging with oxygen absorbers is much easier, and leaves just nitrogen in the packaging. Don’t mess with what works – use oxygen absorbers for your home food storage and leave nitrogen flushing to the experts. (3)