What is the worst packaging material for coffee?

The choice of paper bags as the worst packaging material for coffee is based on their limited ability to protect the coffee from elements that can compromise its quality. Paper is permeable and does not provide an effective barrier against moisture, oxygen, light, and volatile compounds, all of which can quickly degrade the freshness and flavor of coffee.

Moisture can cause mold growth and adversely affect the sensory characteristics of the coffee, while exposure to oxygen can lead to oxidation, promoting stale flavors. Additionally, light can cause a breakdown of the flavors in coffee, further diminishing its quality over time.

On the other hand, the other packaging materials mentioned—plastic bags, glass jars, and foil pouches—offer better protective qualities. Plastic bags can be resealable and are often lined to provide a barrier, glass jars are airtight and protect against light, and foil pouches can effectively shield coffee from moisture, oxygen, and light. Thus, when considering the preservation of coffee's quality, paper bags are at a disadvantage.