An oxygen absorber or oxygen scavenger is a porous sachet that removes the oxygen from the atmosphere. The absence of oxygen prolongs the shelf life of food products. They are commonly used in food packaging to:

• help retain the original flavour, colour, smell and texture,
• inhibit oils in foods from becoming rancid, and
• prevent the growth of oxygen-loving microorganisms such as bacteria, mould and fungi which leads to food spoiling.

Oxygen absorbers use the available moisture in the food and air to cause the iron particles in the sachet to "rust", thereby removing the available oxygen in the air. The food packaging is then left with a higher concentration of nitrogen, which are better conditions for a longer shelf life.  Trapping the oxygen usually generates a small amount of heat.

When would I typically use oxygen absorbers?

• Pasta and noodles
• Rice, grain, pasta, seeds & nuts
• Dried fruits & vegetables
• Spices, seasonings & herbs
• Coffee, tea, cocoa & confectionary
• Processed, smoked & cured meats
• Bakery goods such as flat breads, cakes, pastries
• Pharmaceuticals, vitamins & herbal medicines
• Diagnostic kits devices
• Pet foods & Birdseed
• Stationery and artwork preservation

How do I know if my oxygen absorber is working?

A new oxygen absorber will have a loose powdered feel when pinched. It should feel free of clumps and may feel warm (a by-product of the absorber working in a moist environment).  Spent (or expired) absorbers can feel hard or clumpy to touch.

Oxygen absorbers once exposed to the atmosphere begin to get to work immediately. That is why, we suggest that unused oxygen absorbers should be resealed within 15 minutes to ensure the integrity of the product is maintained.

I don't need to use them all, how can I store my oxygen absorbers, so they last?

Store oxygen absorbers at room temperature (5C to 30C), away from direct sunlight. They should be stored in their sealed package or a glass jar with a gasketed lid. Select the smallest glass jar possible to minimise the oxygen the absorbers will remove from the jar. Oxygen absorbers in a well-sealed container will cause the lid to pop down.

How quickly oxygen absorbers remove oxygen from the atmosphere will depend on the conditions. In dryer climates, it may take up to a week for absorbers to fully activate.  Warmer, humid climates however accelerate the process and may take only 48 hours for the same result.

Oxygen Absorbers trap oxygen. Given that air comprises 20% oxygen and 80% nitrogen, the absorber will only be removing the 20% of the atmosphere that is oxygen. The volume of nitrogen remaining will mean your bag will not deflate to the extent of the bag becoming hard or rigid.

If I use vacuum packaging or nitrogen flushing to package my goods, do I still need to use oxygen absorbers? 

Both these methods are used to remove the oxygen content from a package. Vacuum packaging achieves this by sucking out all air and then sealing the package. Nitrogen flushing forces the heavier nitrogen gas into packaging pushing out the oxygen content.  In both instances, some oxygen remains. It is estimated that when these methods are used there can be 2 – 3% of oxygen remaining. Oxygen Absorbers can then be used to capture the residual oxygen present.

The factors to consider when calculating how many oxygen absorbers you require are:

• The volume of the sealed package
• The volume occupied by the food product.

For those who like the numbers, the formula is: