Oxygen absorbers employ a foundational metal (iron) and a simple chemical reaction (oxidation) to effectively eliminate and trap oxygen within their enclosed packets. Upon opening a packet, you'll notice a dark gray or black substance, which consists of powdered iron. As the absorber is utilized, the material inside gradually becomes slightly rigid and crunchy, eventually taking on a reddish-brown hue.
How do I use oxygen absorbers with mylar bags?
Each oxygen absorber is designated with a rating indicating the volume of oxygen it can absorb, typically measured in cubic centimeters (CC). For instance, a 300cc oxygen absorber has the capacity to remove 300cc (0.3 liters) of oxygen from a sealed environment such as a Mylar bag. However, considering that approximately 80% of air consists of nitrogen, the absorber only needs to eliminate the remaining 20% composed of oxygen. Following the 4:1 or 80:20 ratio, an oxygen absorber can effectively clear an airspace approximately five times its designated rating. Thus, for example, a 300cc oxygen absorber can clear the air from an empty bag or container with a volume of up to 1.5 liters (300cc x 5).
However, in practical use, since our bags are predominantly filled with food rather than air, we can employ a higher ratio of oxygen absorber to bag size. This explains why, for instance, we approximate that a 300cc oxygen absorber can adequately clear the oxygen from a one-gallon Mylar bag.
How many oxygen absorbers should I use?
A commonly recommended guideline is to utilize 300-500cc of oxygen absorber per gallon of stored food. Here's a simplified chart illustrating this principle:
1 Quart Bag: 100cc oxygen absorber
1 Gallon Bag: 1-2 300cc oxygen absorbers
2 Gallon Bag: 2-500cc oxygen absorbers or 1-1000cc oxygen absorber
My bag didn't shrink/contract, are my absorbers bad?
In nearly all instances (99.99%), this is certainly not the case! Our oxygen absorbers are trusted by food processing companies globally, and they wouldn't endorse a product that only functions intermittently. There are several factors that might prevent your bags from contracting. For instance, certain types of foods, such as dense items like flour or fluffy ones like oats, may rarely cause contraction. Another reason for non-contraction could be that the absorbers are solely eliminating the 20% oxygen we discussed earlier, leaving the bag with the remaining 80% nitrogen (which is inert and thus harmless). Sometimes, even when storing the same type of food, you might notice discrepancies where some bags contract while others do not. This could stem from minor differences in the amount of headspace (air) present in each bag.
Furthermore, when using oxygen absorbers with foods possessing very low moisture content, they may take longer to activate, which is perfectly normal. While oxygen absorbers can sometimes work within hours, in extremely dry conditions, it may take up to a week or more to completely remove oxygen from a container.
Lastly, some individuals may not employ a sufficient quantity of oxygen absorbers for their storage needs. It's important to remember that if you're using 5-gallon bags but purchasing 100cc oxygen absorbers, you'll need to use 20 or more absorbers per bag!
