Oxygen Absorbers Information
Oxygen absorbers are a critical tool in food preservation, particularly for long-term storage. However, their application extends beyond food to pharmaceuticals, electronics, and archival preservation. Discount Mylar Bags has had research labs as such as Los Alamos and Oak Ridge National Laboratory as well as the Department of Defense and dozens of university research labs use our products for non-food storage uses.
Definition and Purpose
Oxygen absorbers are small packets or devices designed to remove oxygen from enclosed environments, preventing oxidation and spoilage. They are especially vital in food storage, where oxygen can lead to rancidity, color changes, and microbial growth, thus extending shelf life. Their use can also protect pharmaceuticals from degradation and preventing corrosion in electronics, as well as preserving artifacts in museums and archives by controlling oxygen levels.
Mechanism of Action
The primary mechanism involves iron powder reacting with oxygen to form iron oxide, described by the chemical equation:
4Fe+3O2→2Fe2O3
This reaction removes oxygen from the container, creating a low-oxygen, nitrogen-rich environment. Some absorbers include sodium chloride to catalyze the reaction, particularly in low-humidity conditions, enhancing their effectiveness. They are typically enclosed in porous sachets, allowing oxygen to permeate while containing the iron powder, and can reduce oxygen levels to below 0.01%, as noted in studies on food packaging.
Types of Oxygen Absorbers
There are several main types for food storage:
- Type B Absorbers: These require moisture from the food to activate, suitable for items like beef jerky or partially dehydrated fruits with inherent moisture.
- Type D Absorbers: These contain their own moisture, ideal for dry-pack canning where food is thoroughly dried, offering versatility for a broader range of products.
- Discount Mylar Bags Slow-Acting Oxygen Absorbers are designed specifically to react slower than normal oxygen absorbers. This allows more time to use and store them. It also decreases the amount of catalytic activity, producing less heat which could potentially cause condensation, particularly in freeze dried foods.
This classification helps users select the appropriate type based on food characteristics, ensuring optimal performance.
Applications
Primary Applications
- Food Storage: Prevents oxidation of fats, discoloration, and aerobic microbial growth, extending shelf life for dry goods like rice, beans, pasta, and nuts.
- Pharmaceuticals: Protects drugs from oxygen-induced degradation, maintaining efficacy.
- Electronics: Prevents corrosion of metal components, ensuring longevity.
- Museums and Archives: Controls oxygen to preserve artifacts and documents, preventing oxidative damage.
Their versatility makes them a staple in various industries, with significant impact on product quality and safety.
Proper Usage in Food Storage
Effective use requires careful preparation:
- Moisture Control: Food should be dried to less than 12% moisture to prevent botulism poisoning, a critical safety consideration (though that generally occurs at much higher moisture levels). Studies highlight that high moisture can create anaerobic conditions favorable for Clostridium botulinum.
- Size Calculation: Determine the absorber size by calculating residual oxygen. For instance, for a 2-quart bag residual air is 1892 cc, and oxygen is approximately 379 cc (20% of 1892 cc). We recommend a 500cc absorber to account for working type and residual permeation of oxygen into a bag over time.
- Handling: Once opened, many absorbers should be used within 15 minutes to prevent capacity loss. (Discount Mylar Bags oxygen absorbers are over-weighted to allow at least an hour of working time, or 4 hours for our Slow Acting oxygen absorbers). Store unused absorbers in airtight containers (Mason jars with ring and seal lids, Mylar Bags, or the original packaging) to maintain effectiveness.
- Sealing: Ensure containers, such as Mylar bags or mason jars, are sealed airtight post-insertion. Store in cool, dry places away from light and heat to maximize shelf life.
Standard recommendations include:
- 1 quart Mylar Bag: 1 x 100cc oxygen absorber
- 2 Quart Mylar Bag: 1 x 300cc oxygen absorber
- 1 gallon Mylar bag: 1 x 500cc oxygen absorber
- 2 gallon Mylar bag: 2 x 500cc oxygen absorbers
- 5 gallon Mylar bag: 4 x 500cc oxygen absorbers
These guidelines account for headspace and potential air trapped within food, often using larger absorbers for safety. This is intended as a general guide; for more detailed information see our comprehensive sizing guide here: Oxygen Absorber Sizing Guide
Benefits
Oxygen absorbers offer several advantages:
- Extended Shelf Life: By removing oxygen, they minimize spoilage from aerobic microorganisms and oxidation, potentially extending shelf life up to 30 years for dry goods under optimal conditions.
- Improved Food Quality: Maintain color, flavor, and nutritional value, preserving vitamins like A, C, and E that degrade with oxygen exposure.
- Cost-Effective: Compared to vacuum sealing or freezing, they are inexpensive and simple to use, reducing food waste and enhancing emergency preparedness.
Limitations
Despite their benefits, there are limitations:
- Moisture Dependency: Type B absorbers require specific moisture levels, limiting their use with very dry foods, while Type D absorbers are more versatile but still dependent on proper sealing. However, please note, Type D absorbers are VERY rare in the standard prepper/survival market. Both brands of Oxygen Absorber Discount Mylar Bags carry are NOT moisture dependent.
- Anaerobic Risks: Removing oxygen can create conditions for anaerobic bacteria, particularly if moisture exceeds 10%, posing botulism risks, a significant concern highlighted in food safety research.
- Single-Use Nature: They cannot be reused once activated, requiring careful planning to avoid waste.
Storage and Shelf Life of Oxygen Absorbers
- Shelf Life: Unopened, they last 6 months to 2 years, depending on storage conditions. Once opened, use within 15 minutes to prevent activation by ambient air.
- Storage: Store in airtight containers, such as mason jars, to maintain effectiveness. Some users vacuum seal unused absorbers to extend usability.
- Freshness Check: Oxygen Indicators, often included, change color in the presence of oxygen (indicating potential compromise) and pink when oxygen is absent. Alternatively, feel for heat generation; if warm, they’re active, but if hard and crumbly, they may be spent.
- Please note that occasionally Oxyfree oxygen indicators can react to both temperature and humidity as well as the presence of oxygen. These false positives do not indicate the absorbers are bad. As long as your oxygen absorbers were purchased recently (within 12 months) and still have their vacuum seal, they are good.
Conclusion
Oxygen absorbers are a vital preservation tool, offering significant benefits for extending shelf life and maintaining quality, particularly in food storage. Understanding their types, proper usage, and limitations ensures safe and effective application, supporting long-term storage needs across various industries.