The Complete Handbook of Oxygen Absorbers

Chapter 1: Understanding Oxygen Absorbers

The problem oxygen absorbers solve is deceptively simple to state: the oxygen in the air inside a sealed package will destroy the food you are trying to preserve. It causes fats to go rancid, it feeds aerobic bacteria and mold, it oxidizes vitamins like A and C, and it allows insects and their eggs to thrive. Vacuum sealing helps, but it is not a complete solution. A standard vacuum sealer removes most of the air, but it cannot remove the oxygen that is already dissolved in the food itself, nor the oxygen that will slowly permeate through many types of packaging film. Even a flush of nitrogen, common in industrial packaging, typically leaves a residual oxygen level of 1% to 3%. For a long-term storage plan, that remaining oxygen is more than enough to cause significant food degradation over the course of a year or more. Oxygen absorbers exist to eliminate that residual oxygen, taking the internal environment of a sealed package from around 20.9% oxygen down to less than 0.1%.

At its core, an oxygen absorber is a small sachet or packet filled with iron powder and a catalyst, usually a salt like sodium chloride. The entire mechanism relies on a simple oxidation reaction, the same chemical process that causes rust. When the sachet is removed from its airtight barrier packaging and exposed to the air inside a food container, the moisture in that air activates the catalyst. The iron then begins to react