Silica Gel vs Oxygen Absorber

Silica gel and oxygen absorbers are both packaging solutions that protect and preserve products. However, they each work in unique ways and are, therefore, used for different purposes. Because they look similar, the differences between the two often require clarification.

It’s important to understand that silica gel functions mainly through adsorption, where water molecules adhere to the surface of its particles. Its high surface area and porous structure enable it to effectively attract and retain moisture from the air. In contrast, oxygen absorbers work through absorption, involving a chemical reaction that absorbs and removes oxygen from the environment. These absorbers usually contain iron powder, which reacts with the oxygen in the air to create iron oxide (rust), thereby lowering the oxygen levels within the packaging.

To ensure safe and effective use, it’s crucial to select the correct product and follow the guidelines. This article will explain the difference between silica gel and oxygen absorbers to help you make informed choices.

Silica Gel: A Popular Desiccant

Silica gel is a porous form of silicon dioxide that is a type of desiccant. It typically comes in small packets and can adsorb the moisture of up to 40% of its weight at 100% humidity. Silica gel packets can be placed in packaging or sealed containers to prevent condensation and keep products dry in damp and humid conditions.

Silica gel’s ability to combat moisture prevents mould from growing. Together with moisture barrier bags, silica gel packets are often used to package vitamins, shoes, and electronics. As a desiccant, silica gel can also be used to package dried food to help retain the product’s crispness and hardness.

Applications and Uses

Other products and items often packaged with silica gel include:

• Dried flowers
• Seed packets
• Camera and video equipment
• Photos
• Shoes
• Luggage
• Toolboxes
• Important documents
• Non-prescription and prescription medicines
• Gun cases and ammunition cans

Unlike oxygen absorbers, silica gel desiccant is reusable. The desiccant can be regenerated by spreading the desiccant or packets on a baking sheet and placing it in a preheated oven at 250°F (120°C) for about 1-2 hours. Monitor the silica gel during this time to prevent overheating or burning.

The heat from the oven removes moisture from the desiccant, reactivating the silica gel. After the reactivation, place the desiccant or packets in a zip-lock bag and store it in an airtight container to keep moisture at bay, and they will be ready for use when needed. The desiccant can also be repackaged in sealed paper or breathable mesh moisture absorbing bags.

Advantages of Silica Gel

Silica gel is used across many industries and has a number of benefits and uses, including:

• Preserve Product Quality: Silica gel preserves the freshness, texture, and appearance of products.
• Non-Toxic and Non-flammable: While it shouldn’t be ingested, silica gel is chemically inert and non-toxic, making it safe for use in food packaging, pharmaceuticals, and other sensitive industries.
• Moisture Adsorption: Able to adsorb up to 40% of humidity or oxygen of its weight in moisture, protecting products from humidity, mould, and corrosion.
• Reusable: Silica gel can be regenerated by heating, allowing it to be reused multiple times, making it a cost-effective solution.
• Wide Range of Applications: Suitable for various applications, including food packaging, pharmaceuticals, electronics, leather goods, textiles, and logistics.

Find out more about silica gel and how much desiccant bags are needed to protect products within a packaging.

Disadvantages of Silica Gel

Silica gel is generally safe for most people to handle and come into contact with. It is a non-toxic, non-flammable, and non-reactive desiccant that absorbs moisture and keeps products dry. However, there are a few dangers to be aware of when handling silica gel, including:

• Dust: Inhalation of dust from silica gel beads may cause lung irritation and redness when contact with the skin and eyes occurs.
• Risk of Ingestion: Silica gel beads can be a hazard for children and pets if mistakenly consumed, as it quickly adsorbs saliva and may get lodged in the throat or create intestinal blockages.
• Potential for Contamination: If silica gel packets are not handled or stored properly, they can become contaminated with impurities or bacteria. This can compromise their effectiveness and affect the product’s quality.
• Color Indicator Concerns: Silica gel packets that come coated with cobalt chloride beads are toxic and it shouldn’t be used to package food or pharmaceuticals. Ingesting this type of silica can also cause nausea and vomiting.

To minimize the disadvantages of silica gel, it’s important to:

• Handle silica gel carefully: Wear gloves and avoid inhaling dust.
• Store silica gel properly: Keep it in a clean, dry place, away from moisture sources.
• Dispose of silica gel responsibly: Follow local recycling or disposal guidelines
• Consider alternative desiccants: If you are concerned about silica gel’s limitations, explore other desiccant options, such as activated alumina or calcium chloride.

Oxygen Absorbers: A Favoured Absorber

Oxygen absorbers, also known as oxygen scavengers, are small sachets typically filled with iron powder that effectively remove oxygen from packaging environments.

Once exposed to air, the iron powder reacts with the oxygen, oxidising to form rust and simultaneously absorbing the oxygen. This chemical reaction creates an oxygen-free atmosphere within the sealed packaging, which helps to extend product shelf life by preventing oxidation and the growth of aerobic bacteria.

By reducing the oxygen level to 0.01% or less, they help maintain the product’s flavour, colour, and texture while also protecting it from mould, spoilage, and rancidity. Moreover, oxygen absorbers provide an eco-friendly packaging solution, as they can reduce the need for chemical preservatives, offering a safer alternative for consumers.

Some things to know when using oxygen absorbers:

• Avoid Exposure to Air Before Use: Once exposed to air, oxygen absorbers begin to work immediately; frequent exposure will reduce their lifespan.
• Use with Proper Packaging: Once the packaging is opened, take out what is required and store the rest in airtight or vacuum-sealed packaging to prevent additional oxygen from entering and re-oxidising the product.
• Store Unused Oxygen Absorbers Properly: Store the oxygen absorbers in a cool, dry place away from moisture and direct sunlight to maintain their effectiveness.
• Choose the Correct Quantity: Use the appropriate amount of oxygen absorbers for the specific product and packaging. Different products require differing amounts based on their oxygen content and the packaging volume.
• Monitor the Condition of Absorbers: Oxygen absorbers should feel soft and powdery when unused. If they become hard, it means they’ve absorbed sufficient oxygen and are no longer functional.

Applications and Types

Oxygen absorbers are typically available in different sizes to suit various packaging needs, typically from 20 cc to 500 cc. For a 5–6-gallon storage bucket of dried food, two 500 cc oxygen absorber agents should be sufficient. Oxygen absorbers protect foods such as:

• Nuts and seeds: Almonds, walnuts, sunflower seeds, flaxseeds, chia seeds
• Pastries and snacks: Crackers, chips, cookies, granola, mooncakes
• Jerky and Dried Meats: Processed, smoked, cured meats
• Dairy Products:  Butter and Cheese
• Spices and Seasoning: Dried herbs like basil, oregano, thyme; spices like chili powder, turmeric, cinnamon
• Powdered Foods: Flour, powdered milk, baking mixes, pancake mix, protein powder
• Fresh and precooked noodles: Pasta, ramen noodles, rice noodles, instant noodles
• Pet food: homemade pet food, dry pet food, treats
• Candies and confectioneries: Chocolate, hard candies, gummies, marshmallows, lollipops
• Coffee and Tea: Ground coffee, whole beans, tea leaves, tea bags
• Dried fruits and vegetables: Raisins, apricots, apples, mushrooms, spinach, tomatoes

Common Mistakes When Using Oxygen Absorbers

Oxygen absorbers should not be used with certain types of foods. For example, sugar and salt do not require oxygen removal and may harden if stored with oxygen absorbers. Additionally, moist or high-fat foods, such as fresh fruits, vegetables, and high-oil content items, are unsuitable for oxygen absorbers. These foods can spoil due to moisture or fat, even in the absence of oxygen, making oxygen absorbers ineffective in preventing spoilage.

Another mistake associated with oxygen absorbers is opening the packet too soon and failing to place the absorbers in a sealed container quickly. This is a problem, as oxygen absorbers start to work as soon as they are exposed to air, quickly saturating the packet and triggering the need to be replaced with a fresh oxygen absorber.

A good way of checking is to observe the indicator’s colour. Most oxygen absorbers’ packaging features a freshness indicator. It’s typically a little pink paper 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, the packet is saturated and should be discarded. Always store extra absorbers carefully. Good storage practices reduce wastage and promote environmental sustainability.

Advantages of Oxygen Absorbers

Oxygen absorbers are popular for several reasons, and here are some benefits:

• Non-Toxic and Safe for Food Storage: Oxygen absorbers are generally safe and non-toxic for food storage, safe to use, and FDA-approved
• Maintains Quality, Freshness and Flavour: Prevents colour change and  retains the original taste, aroma, and texture of foods
• Prevents Rancidity: Maintains the quality of polyunsaturated fats and oils and prevents them from going rancid
• Inhibits Insect Infestations: Removing oxygen makes the environment inhospitable for insects and prevents infestations
• Reduce Microbial Growth: Effectively reduces the aerobic environment to 0.01% oxygen by absorbing most of the oxygen in the packaging. This inhibits the growth of microorganisms and reduces the risk of foodborne illness
• Prolong Shelf-Life: Extends the shelf-life of foods and sensitive products such as pharmaceutical products . This minimises the need for some preservatives or in some instances, refrigeration.

Disadvantages of Oxygen Absorbers

While oxygen absorbers are very effective, there are some potential disadvantages:

• Limited Capacity: Oxygen absorbers are able to absorb a limited amount of oxygen. If too much oxygen is present, multiple absorbers may be required, which can add to the cost and complexity of packaging.
• Does not prevent all bacteria growth: They may not be effective against certain types of bacteria, mainly anaerobic bacteria, which thrive in oxygen-free conditions.
• Not Suitable for All Foods: They shouldn’t be used with foods with high oil content as they may speed up oxidisation.
• Cannot Be Reused: Oxygen absorbers are single, one-time-use items and they are, not reusable.

To minimise the disadvantages of oxygen absorbers, it is important to:

• Choose the right type of oxygen absorber: Select oxygen absorbers appropriate for the specific product and storage conditions.
• Handle and store oxygen absorbers properly: Follow the manufacturer’s instructions for handling and storage to prevent contamination and maintain their effectiveness.
• Dispose of oxygen absorbers responsibly: Recycle or dispose of oxygen absorbers according to local regulations to minimise environmental impact.
• Consider alternative packaging methods: Other packaging methods may be more suitable for highly perishable products or environments with high humidity levels.

Using Silica Gel and Oxygen Absorber Together

Silica gel and oxygen absorbers are commonly used to preserve and protect products from degradation, but they work slightly differently. Silica gel absorbs moisture, while oxygen absorbers remove oxygen from the surrounding environment.

In food packaging, combining silica gel and oxygen absorbers can help to maintain freshness and extend the shelf life of the food. Generally, using both together is safe.

However, using these products correctly and in the appropriate quantities is essential. If too much of either product is used, it can affect the effectiveness of the other. In addition, it is important to follow the guidelines provided with each product to ensure safe and effective use.

Conclusion

Both silica gel and oxygen absorbers or scavengers are effective packaging solutions for preserving and protecting products from moisture and oxygen. It is important to consider each option’s potential disadvantages or limitations, such as the cost or potential impact on the product’s quality.

The choice between silica gel and oxygen scavengers depends on the product’s specific needs, such as the moisture or oxygen content and the desired shelf life:

• Silica gel:  suitable for moisture-sensitive products or high-pressure packaging environments.
• Oxygen absorbers: more appropriate for products susceptible to oxidation or spoilage caused by oxygen exposure. 

Ultimately, choosing between silica gel and oxygen scavengers depends on the specific needs and goals of the product. Both options can effectively extend shelf life and protect the product’s quality when used correctly. Watch the video below to learn more about the differences between oxygen absorbers and silica gel.

At Stream Peak, our silica gel packets are manufactured under ISO 9001 and 14001 certifications, ensuring top quality standards. Rigorous testing is conducted in our in-house lab to maintain product reliability. We also supply oxygen absorbers made with advanced Japanese technology and materials. Engage with our engineering experts for more information.