Silica Gel vs Oxygen Absorber
Published On:August 30, 2019 Revised On:March 22, 2023

Silica Gel vs Oxygen Absorber

These two packaging solutions often need clarification from each other as they look similar but are very different. To understand the characteristics of oxygen absorbers and silica gel, let us first understand what makes them different.

In this post, we will explain the difference between Silica Gel and Oxygen Absorbers.

Silica Gel

Silica Gel is a porous form of silicon dioxide and can absorb up to 40% of its weight. The moisture absorber prevents condensation and keeps products dry in damp and humid conditions.

This chemical’s ability to combat moisture prevents mould from growing.  Silica gel is often used with moisture barrier bags, vitamins, shoes and electronics. As a desiccant type, the moisture absorber can be used in dried food packaging to help retain the product’s crispness and hardness. Find out more about silica gel here and how many desiccant bags to use in packaging.

Some of the other items where Silica Gel can come in handy for packaging are:

  • Camera and video equipment
  • Drying flowers
  • Photos
  • Gun cases and ammunition cans
  • Non-prescription and prescription medicines
  • Toolboxes
  • Seed packets
  • Important documents
  • Reduce mould on shoes
  • Luggage, etc

Unlike oxygen scavengers, silica gel desiccant is reusable. To reactivate the used silica gel, spread the beads thinly on a baking sheet and bake for 15 minutes at 79.4°C in a preheated oven.

The heat from the oven absorbs moisture from the desiccant, which reactivates the silica gel. Place the desiccant bag in a zip lock bag to keep moisture at bay, and it will be ready for use when needed.

Some interesting ways to reuse silica gel are to prevent rust on razor blades, prevent car windscreens from steaming, and stop seeds from sprouting.

Advantages of Silica Gel

Silica gel is widely used across many industries. This prevalence is based on several factors, including that it is:

  • Not flammable, non-toxic and chemically unreactive
  • Reusable
  • Suitable for conventional packing
  • Able to absorb approximately 40% of humidity or oxygen of its weight
  • Available in various sizes for different applications
  • Of indefinite shelf life when stored in the right conditions
  • Eliminate odour

Disadvantages of Silica Gel

There are some cons to using silica gel. Be aware of these disadvantages:

  • Dust from silica gel beads may cause irritation and redness when in contact with the skin and eyes
  • Inhalation may cause lung irritation
  • Beads can be a choking hazard for children if mistakenly consumed

Oxygen Absorbers

Oxygen absorber vs Silica gel

Oxygen Absorbers, also known as oxygen scavengers, are mini sachets that contain iron fillings, clay, and salt. The clay produces moisture, which combines with salt to activate the iron fillings and absorb oxygen. This process begins as soon as the oxygen absorber packet is exposed to the air. Immediately upon exposure, the iron fillings oxidise, forming rust and releasing nitrogen.

Nitrogen helps to keep food fresher for a more extended period, and the lack of oxygen in the packaging helps to keep weevils and other insects from infesting the food item.

Some other things to know about Oxygen Absorbers are:

  • Avoid exposing oxygen absorbers to the air; frequent exposure will reduce the lifespan
  • Once the packaging is opened, take out what is required and store the rest in an airtight jar
  • For oxygen scavengers to be effective, the right amount must be used for the food packaging
  • Salt and sugar do not need oxygen for long-term storage

Oxygen absorbers come in various sizes, typically from 20 cc to 500 cc. For a 5-6 gallon storage bucket, two 500 cc oxygen absorber agents should be sufficient.

Oxygen absorbers are commonly used for foods that spoil quickly, such as nuts and snacks, whole-fat dry foods, processed, smoked and cured meats, dairy products, mooncakes, spices and seasoning, and flour products. They are also used for other types of food, such as fresh and precooked noodles, pet food, pastries, candies and confectioneries, coffee, tea, dried fruits and vegetables.

Common Mistakes When Using Oxygen Absorbers

Oxygen absorbers begin to work as soon as they are exposed to air. A common mistake is to open the packet too soon and fail to place the absorbers in a sealed container quickly. This is a problem as the packets will absorb too much oxygen and need more iron to preserve the food.

Another mistake is using depleted absorbers, which can be checked by observing the indicator’s colour. Most oxygen scavengers’ packaging contains a little pink indicator that turns blue if the oxygen scavenger has expired or is no longer useful.

Another method of checking is to shake the packet. If one can hear and feel the loose powder, it’s good to use. If it’s hard or solid instead, the packet is saturated and should be discarded.

Always store extra absorbers carefully. Good storage practices reduce wastage and are also environmentally friendly.

Advantages of Oxygen Absorbers

Oxygen absorbers are popular for several reasons. Here are some of the most important:

  • Non-toxic, safe to use, and FDA approved
  • Prevent colour change and infestation in food packages
  • Maintain food quality, e.g., delaying discolouration and darkening in fruits and vegetables
  • Maintain the quality of polyunsaturated fats and oils and prevent them from going rancid
  • Extend the shelf-life of pharmaceutical products and minimise the need for some preservatives

Oxygen absorbers can effectively reduce the aerobic environment to 0.01 per cent oxygen by absorbing most of the oxygen in the packaging. This inhibits the growth of microorganisms or fungi in dairy, pastries, nuts, and fish products.

Disadvantages of Oxygen Absorbers

While oxygen absorbers are very effective, they do have certain shortcomings:

  • Foods with low oil content
  • May cause botulism poisoning if used incorrectly
  • Able to absorb a limited amount of oxygen
  • Single, one-time use

Using Silica Gel and Oxygen Absorber Together

It is not recommended to use silica gel and oxygen absorber together. Oxygen absorbers require moisture to work, while silica gel absorbs moisture. When placed in the same space, silica gel will render the oxygen absorbers useless, halting the activation process through a lack of oxygen.


Remember, oxygen scavengers only absorb oxygen, not moisture or air, while silica gel absorbs moisture. To limit the oxygen exposure level, use an oxygen scavenger and extend the freshness of food products with the proper packaging. On the other hand, enhance the life span of food products with silica gel to reduce the humidity level in the food or other packaging, prolonging shelf life.

Watch the video below to learn more about the differences between Oxygen Absorbers VS Silica Gel!