The heat generated by oxygen absorbers during the oxidation reaction is typically too small to cause any damage to food. While they generate heat as they work, the temperature rise is generally slight and dissipates naturally within the packaging.
Oxygen absorbers remove oxygen from the air and release heat during the process.
However, the heat generated is minimal and typically not sufficient to cause any damage to the food inside a sealed package. That said, there are a few situations in which concerns about heat affecting food quality might arise. Let’s explore how the reaction works, how much heat is generated, and whether it poses any risks to the food.
Understanding the Chemical Reaction in Oxygen Absorbers
Oxygen absorbers function by using iron powder that reacts with oxygen (O₂) in the air, converting it into iron oxide (rust). This chemical reaction is exothermic, meaning it releases heat as a byproduct. The amount of heat released is relatively small because the reaction happens at a slow rate over time. Typically, the temperature rise is moderate, and most well-designed oxygen absorbers are engineered to guarantee that the heat generated dissipates without affecting the contents of the package.
How Much Heat Is Generated?
The heat produced by oxygen absorbers is generally quite low, especially in small units used in food packaging. For example, oxygen absorbers commonly used in home food storage (such as 100cc to 500cc units) do not generate enough heat to cause noticeable changes in the temperature inside the package.
- The chemical reaction is: 4Fe(s)+3O2(g)→2Fe2O3(s)+heat
- Water (moisture) catalyzes the reaction
- Water is not generated
Typical Temperature Increase: The temperature inside the package may increase by a few degrees during the oxidation process. In most cases, this slight rise in temperature has no significant effect on the food being preserved.
- Dissipation: Because the process happens slowly, the heat is distributed evenly and dissipated through the packaging materials, making it unlikely for hot spots to form.
Could the Heat Damage Food?
Under normal circumstances, the heat generated by oxygen absorbers is not enough to damage food. However, certain conditions could potentially raise concerns:
a. Large Absorbers in Small Packages
If a large oxygen absorber (such as a 2000cc absorber designed for bulk storage) is used in a small package, it may release more heat than necessary for that small volume of air. In this case, the heat may accumulate, potentially leading to a higher temperature inside the package than would normally occur with a properly sized absorber.
- Risk: In a very small, enclosed package, heat from an oversized absorber could potentially cause delicate foods to become slightly warm, possibly altering their texture (e.g., causing chocolate to soften or affect the crispness of freeze-dried items).
- Solution: Always use oxygen absorbers that are appropriately sized for the package to avoid unnecessary heat buildup.
b. Highly Temperature-Sensitive Foods
Certain foods, such as chocolate, candies, or gelatin-based products, are more sensitive to temperature changes and may soften or become sticky when exposed to even slight increases in temperature. These foods could be affected if the heat from the oxygen absorber is not dissipated quickly enough.
- Risk: If the food is highly temperature-sensitive and there is not enough airflow or space in the packaging to allow heat dissipation, the food might be more vulnerable to textural changes.
- Solution: Ensure proper air circulation around the package or store temperature-sensitive foods in cooler environments when using oxygen absorbers.
c. Bulk Storage in Confined Spaces
In bulk storage environments, where large quantities of oxygen absorbers are used in confined spaces, there could be more noticeable heat generation, especially if many absorbers are active simultaneously.
- Risk: In bulk storage with a large number of absorbers working at once, there might be a slight risk of localized heat buildup, especially in tightly packed or insulated storage areas. This could, in theory, lead to heat-sensitive items being affected.
- Solution: Allow for adequate ventilation and spacing in large-scale storage settings to help dissipate any minor heat generated by the absorbers.
How Heat Could Affect Different Types of Food
Freeze-Dried Foods
Freeze-dried foods are generally resilient and unaffected by small temperature changes. However, their texture (particularly crispiness) could be impacted if exposed to too much moisture or heat, causing them to lose their crunchy quality.
- Effect: Minor heat generation from oxygen absorbers is unlikely to damage freeze-dried foods. However, if improperly stored in a warm or poorly ventilated area, there could be a slight impact on texture.
Chocolate, Candies, and Sensitive Confectionaries
As mentioned earlier, chocolate and candies are more sensitive to temperature fluctuations. Chocolate, in particular, can soften and lose its structure if exposed to heat, even at relatively low temperatures.
- Effect: These products could soften or change consistency if the heat from an oxygen absorber builds up in a small package, especially if not stored in a cool, dry place.
Powdered Goods (Flour, Coffee, etc.)
Powdered foods, such as flour, powdered milk, or instant coffee, are more stable and less likely to be impacted by slight temperature increases. However, moisture is a much bigger threat to powdered products than heat.
- Effect: Small amounts of heat will not typically affect powdered products, but ensuring the package remains dry is essential for preserving quality.
Precautions to Take to Avoid Any Issues
To ensure that the heat generated by oxygen absorbers does not affect your food, follow these best practices:
a. Use the Correct Size of Oxygen Absorber
Choose an oxygen absorber that is appropriately sized for the package. Overusing large oxygen absorbers in small packages increases the chance of heat buildup. Oxygen absorbers are typically available in various sizes (e.g., 50cc, 100cc, 300cc, 500cc), so select the right size based on the volume of air in the packaging.
b. Ensure Proper Ventilation
If you are storing multiple packages with oxygen absorbers, particularly in bulk or confined spaces, ensure there is enough airflow around the packages. This helps prevent heat from accumulating in one area.
c. Store in a Cool, Dry Place
Store your packaged food in a cool, dry location. Even though oxygen absorbers don’t release a significant amount of heat, external environmental factors such as room temperature and humidity can affect the food’s overall quality. Proper storage will mitigate the effects of any heat generated by the oxygen absorber.
d. Use Layered Packaging
If the food is highly sensitive to temperature or moisture, consider using layered packaging materials like Mylar bags within a rigid plastic or metal container. This extra layer helps insulate the food and keep heat from building up inside the inner packaging.
Conclusion: Can the Heat from Oxygen Absorbers Damage Food?
In summary, the heat generated by oxygen absorbers during the oxidation reaction is typically too minimal to cause any damage to food. While the reaction is exothermic, the temperature rise is generally slight and dissipates naturally within the packaging. Only in very rare circumstances—such as using oversized oxygen absorbers in very small packages or storing heat-sensitive foods in warm, poorly ventilated areas—could the heat potentially affect the food’s texture.
To avoid any potential issues, it’s best to:
- Use the appropriate size of oxygen absorber for your packaging.
- Ensure that food is stored in cool, dry, and well-ventilated environments.
- Pay special attention to packaging temperature-sensitive items, such as chocolates or freeze-dried foods, to ensure their quality is maintained.
By following these guidelines, you can safely use oxygen absorbers without concern about heat damaging your preserved foods.