Skip to content


6 min read

Storing Unused Oxygen Absorbers

Oxygen absorbers or oxygen scavengers, as they are also known, remove free oxygen from a seal environment by the process of oxidation.

In the specific case of our oxygen absorbers and Mylar bags, iron powder in the absorber becomes iron oxide, and free oxygen from the air inside the bag is removed.

At Mylar Shop we selling only branded OxyFree oxygen absorbers sourced direct from OxyFree. These are available in 5 sizes; 20cc,50cc,100cc300cc and 2,000cc20cc oxygen absorbers come in standard packs of 400 pieces. 50cc oxygen absorbers come in standard packs of 200 pieces, 100cc absorbers come in standard packs of 100, 300cc absorbers come in standard packs of 20 and 50, and 2,000cc absorbers come in standard packs of 10. All full packs come with an OxyEye oxygen indicator, which changes colour from pink to dark blue/purple when exposed to oxygen.

We understand that customers may want to use fewer oxygen absorbers than the standard pack sizes at a time. For this reason, we repackage and sell our 20cc,50cc,100cc300cc and 2,000cc absorbers in smaller pack sizes. These are repackaged by us from the full packs, and very quickly vaccum sealed to ensure freshness.

There is obviously a price premium on our smaller packs than the full packs, which reflects the extra labour and materials required to repackage them.

Some customers may prefer to buy full packs, and store unused oxygen absorbers to be used at a later date. This is fine, and works well, but it’s important to remember what oxygen absorbers do, and how they work. They will start reacting shortly after being exposed to oxygen, so you must work as quickly as possible. Fill your bags with the stored material, whether food, medicine, clothing, or whatever you are preserving, before opening the oxygen absorbers.

OxyFree oxygen absorbers start reacting within a few minutes of being exposed to oxygen, and the full reaction from iron to iron oxide takes around 24 hours. The chemical reaction of oxidation gives off heat, so if you can feel the absorber becoming warm in your hand, it has started working.

OxyFree recommend applying the absorber within 60 minutes of opening, though obviously the faster you put the absorber in the bag, the more absorption capacity the absorber retains.

Unused oxygen absorbers can be vacuum sealed using a vacuum sealing machine, or they can be sealed inside a Mylar bag, or in an airtight jar or other container.

When storing unused oxygen absorbers it’s vital to have as little air (and thus oxygen) in contact with them as possible. If using a Mylar bag, use as small a bag as you can comfortably fit the unused absorbers in whilst still being able to heat seal it. If using a jar or other airtight container, use as small a container as possible. In both cases, of course, the airtightness of the seal is vitally important, and it must be understood that no bag, jar or other container is entirely airtight, so oxygen absorbers stored in this way will not last indefinitely.

A good tip that we received from a customer (thank you Maureen), is to fill any unused space in the jar or bag with rice, to reduce the amount of free air available.

One question we are often asked is how do you tell the difference between a used oxygen absorber and a fresh one, if there is no oxygen indicator in the package

The answer is that you can feel it. A fresh absorber has the feel in the hand of wet sand, it’s soft and pliable. A used absorber feels like hard grit. Iron oxide is essentially rust, so a used absorber feels like rust inside the sachet.

If you have any questions about the storage of oxygen asborbers, or any other queries, please contact us.

You may also be interested in...

How Many Oxygen Absorbers to Use?

15 November, 2023

How Many Oxygen Absorbers to Use?

How Many Oxygen Absorbers should I use? What are the Recommended Amounts of Oxygen Absorbers? If the chart below doesn’t answer your specific question, get in touch with the Mylar Shop team. Mylar Bag Size Rice/Wheat/Grains/Flour(More Dense/Less Air Inside Mylar Bag) Beans/Pasta(Less Dense/More Air Inside Mylar Bag) MYLAR FOOD STORAGE BAGS: Mylar Pouch – 7.5cmContinue reading "How Many Oxygen Absorbers to Use?"

Learn more...
DogProof Mylar Bags – Are Mylar Bags Used to Store Drugs?DogProof Mylar Bags – Are Mylar Bags Used to Store Drugs

15 November, 2023

DogProof Mylar Bags – Are Mylar Bags Used to Store Drugs?

Mylar as a material has many useful properties, which when combined can offer a unique storage and packaging solution. The barrier protection of metallised plastic bags, such as Mylar, is the main reason why so many different industries use Mylar as a material. This barrier protection, combined with the relative lightness, strength and flexibility thatContinue reading "DogProof Mylar Bags – Are Mylar Bags Used to Store Drugs?"

Learn more...

Please fill in the Contact Form

Your opinion is important to the team at Mylar Shop so please do not hesitate to get in contact with us!