Oxygen absorbers work by removing oxygen from the air inside food packaging, which extends shelf life and keeps food fresh. This process creates a small amount of heat, known as an “exothermic reaction.” Although this reaction releases heat, it’s usually not enough to harm the food. However, there are a few scenarios where the heat could potentially impact food quality. Let’s explore how this process works, the amount of heat produced, and whether it’s something to be concerned about.
1. How the Exothermic Reaction Works in Oxygen Absorbers
Oxygen absorbers use iron powder to capture oxygen (O₂) in the air, turning it into iron oxide (or rust). This chemical reaction releases heat as a byproduct. The reaction formula is:
4Fe + 3O₂ → 2Fe₂O₃ + heat
The heat released is minimal because the reaction happens gradually. High-quality oxygen absorbers are designed to spread this heat evenly, so the temperature increase doesn’t impact the food inside the package.
2. How Much Heat is Actually Released?
The heat produced by most oxygen absorbers used in food packaging is quite low, especially for small absorbers (such as 100cc to 500cc units) commonly used for home storage.
- Temperature Increase: During the reaction, the temperature inside the package may go up by a few degrees, but this is usually too small to impact the food.
- Heat Dissipation: Because the reaction is slow, heat is evenly spread out, so it doesn’t form “hot spots” within the package.
3. Could This Heat Harm the Food?
Under normal conditions, the heat from oxygen absorbers shouldn’t damage food. However, certain conditions might lead to slight concerns:
a. Using Large Absorbers in Small Packages
If you use an oversized oxygen absorber (such as a 2000cc absorber) in a small package, it might release more heat than necessary for that small space, causing a slight temperature increase.
- Risk: In a very small, enclosed package, this extra heat could warm up delicate foods, like chocolate, which might soften or lose its crunchiness.
- Solution: Choose an oxygen absorber that fits the package size to avoid excess heat buildup.
b. Temperature-Sensitive Foods
Certain foods, such as chocolate, candy, and gelatin-based treats, are more sensitive to heat changes. If the heat from an oxygen absorber doesn’t escape quickly, these foods could become soft or sticky.
- Risk: Without airflow or enough space in the package, the food might soften or change texture slightly.
- Solution: Allow for air circulation around the package or store temperature-sensitive foods in cool areas.
c. Bulk Storage with Many Oxygen Absorbers
In large storage areas where many oxygen absorbers are used in small spaces, the heat produced could add up.
- Risk: In bulk storage, where many absorbers are used at once, there might be a chance of heat buildup in tightly packed or insulated areas, which could affect heat-sensitive items.
- Solution: Provide enough ventilation and spacing to help release any extra heat in large-scale storage.
4. How Heat Can Affect Different Foods
- Freeze-Dried Foods
Freeze-dried foods are durable and usually aren’t impacted by small temperature changes. However, they could lose some crunch if exposed to too much heat or moisture. - Chocolate, Candies, and Delicate Treats
Chocolate and some candies can soften with slight heat increases. If the package warms up due to an oversized oxygen absorber or high room temperature, they may lose texture. - Powdered Goods (Flour, Coffee, etc.)
Powdered foods, like flour and instant coffee, aren’t usually affected by slight temperature changes, but keeping them dry is crucial to preserve quality.
5. Tips to Prevent Any Heat-Related Issues
To ensure that oxygen absorbers don’t affect your food quality, follow these tips:
- Choose the Right Size
Use an oxygen absorber that matches your package size. Oversized absorbers in small packages can increase the chance of heat buildup. - Allow for Ventilation
If you’re storing multiple packages in a small area, make sure there’s enough airflow to let heat escape, especially in bulk storage. - Store in a Cool, Dry Place
While oxygen absorbers don’t create much heat, environmental factors like room temperature and humidity can affect food quality. Cool, dry storage will help maintain your food. - Use Layered Packaging
For sensitive foods, consider adding layers, like Mylar bags, within a sturdy plastic or metal container. This helps keep heat from affecting the inner packaging.
Conclusion: Is the Heat from Oxygen Absorbers a Problem?
In general, the small amount of heat produced by oxygen absorbers is not enough to damage food. Though this process creates a little warmth, it’s usually so minor that it dissipates quickly within the package. Only in rare cases, like using a large absorber in a tiny package or storing heat-sensitive items in hot spaces, could the heat have an effect.
To ensure safe food storage, remember to:
- Pick the right size oxygen absorber for your package.
- Store food in cool, dry, well-ventilated spaces.
- Use extra protection for temperature-sensitive foods, like chocolate or freeze-dried snacks.
Following these steps will help you safely use oxygen absorbers without worrying about heat impacting your stored foods.