Moisture Barrier Bags & Desiccants — Protecting Humidity-Sensitive Shipments
Moisture damage is an underappreciated shipping risk — electronics, food, printed goods, and leather products can all be damaged by humidity during transit. A sealed corrugated box doesn't protect against humidity; moisture permeates cardboard readily. For humidity-sensitive products, moisture barrier bags and desiccants are the solution.
Types of Moisture Barrier Bags & Desiccants
Foil moisture barrier bags (MBB)
Multi-layer foil-laminate bags with heat-seal closure — the strongest moisture barrier available for packaging.
Best for: Electronic components, PCBs, food products, moisture-sensitive pharmaceuticals
Vacuum seal bags
Polyethylene/nylon bags with airtight zipper or heat seal — removes air along with moisture.
Best for: Clothing storage shipments, food, leather goods, anything needing both moisture and oxygen exclusion
Silica gel desiccant packets
Silica gel absorbs moisture from inside a sealed package — does not require a foil bag to work.
Best for: Shoes, leather goods, electronics in standard bags, any sealed package with humidity risk
Molecular sieve desiccants
More aggressive moisture absorption than silica gel — maintains lower relative humidity.
Best for: Pharmaceutical components, precision optical equipment, sensitive electronics
Practical Tips
- •Desiccants extend the time a sealed package stays dry but don't work forever — size desiccant quantity to the transit time and bag volume
- •Standard silica gel unit: 1 gram of silica gel per 1 cubic foot of bag volume for standard transit (under 7 days)
- •Moisture barrier bags must be heat-sealed or properly ziplock-sealed — an open top defeats the purpose entirely
- •For electronics shipped internationally (longer transit, varied humidity climates), use both MBB and silica gel desiccant together
- •Include humidity indicators (color-change cards) in high-value sensitive shipments so receivers can confirm moisture exposure during transit
Frequently asked questions
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